src/share/vm/opto/divnode.cpp

Tue, 02 Nov 2010 09:00:37 -0700

author
kvn
date
Tue, 02 Nov 2010 09:00:37 -0700
changeset 2269
ae065c367d93
parent 1907
c18cbe5936b8
child 2314
f95d63e2154a
permissions
-rw-r--r--

6987135: Performance regression on Intel platform with 32-bits edition between 6u13 and 6u14.
Summary: Use hardware DIV instruction for long division by constant when it is faster than code with multiply.
Reviewed-by: never

     1 /*
     2  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 // Portions of code courtesy of Clifford Click
    27 // Optimization - Graph Style
    29 #include "incls/_precompiled.incl"
    30 #include "incls/_divnode.cpp.incl"
    31 #include <math.h>
    33 //----------------------magic_int_divide_constants-----------------------------
    34 // Compute magic multiplier and shift constant for converting a 32 bit divide
    35 // by constant into a multiply/shift/add series. Return false if calculations
    36 // fail.
    37 //
    38 // Borrowed almost verbatim from Hacker's Delight by Henry S. Warren, Jr. with
    39 // minor type name and parameter changes.
    40 static bool magic_int_divide_constants(jint d, jint &M, jint &s) {
    41   int32_t p;
    42   uint32_t ad, anc, delta, q1, r1, q2, r2, t;
    43   const uint32_t two31 = 0x80000000L;     // 2**31.
    45   ad = ABS(d);
    46   if (d == 0 || d == 1) return false;
    47   t = two31 + ((uint32_t)d >> 31);
    48   anc = t - 1 - t%ad;     // Absolute value of nc.
    49   p = 31;                 // Init. p.
    50   q1 = two31/anc;         // Init. q1 = 2**p/|nc|.
    51   r1 = two31 - q1*anc;    // Init. r1 = rem(2**p, |nc|).
    52   q2 = two31/ad;          // Init. q2 = 2**p/|d|.
    53   r2 = two31 - q2*ad;     // Init. r2 = rem(2**p, |d|).
    54   do {
    55     p = p + 1;
    56     q1 = 2*q1;            // Update q1 = 2**p/|nc|.
    57     r1 = 2*r1;            // Update r1 = rem(2**p, |nc|).
    58     if (r1 >= anc) {      // (Must be an unsigned
    59       q1 = q1 + 1;        // comparison here).
    60       r1 = r1 - anc;
    61     }
    62     q2 = 2*q2;            // Update q2 = 2**p/|d|.
    63     r2 = 2*r2;            // Update r2 = rem(2**p, |d|).
    64     if (r2 >= ad) {       // (Must be an unsigned
    65       q2 = q2 + 1;        // comparison here).
    66       r2 = r2 - ad;
    67     }
    68     delta = ad - r2;
    69   } while (q1 < delta || (q1 == delta && r1 == 0));
    71   M = q2 + 1;
    72   if (d < 0) M = -M;      // Magic number and
    73   s = p - 32;             // shift amount to return.
    75   return true;
    76 }
    78 //--------------------------transform_int_divide-------------------------------
    79 // Convert a division by constant divisor into an alternate Ideal graph.
    80 // Return NULL if no transformation occurs.
    81 static Node *transform_int_divide( PhaseGVN *phase, Node *dividend, jint divisor ) {
    83   // Check for invalid divisors
    84   assert( divisor != 0 && divisor != min_jint,
    85           "bad divisor for transforming to long multiply" );
    87   bool d_pos = divisor >= 0;
    88   jint d = d_pos ? divisor : -divisor;
    89   const int N = 32;
    91   // Result
    92   Node *q = NULL;
    94   if (d == 1) {
    95     // division by +/- 1
    96     if (!d_pos) {
    97       // Just negate the value
    98       q = new (phase->C, 3) SubINode(phase->intcon(0), dividend);
    99     }
   100   } else if ( is_power_of_2(d) ) {
   101     // division by +/- a power of 2
   103     // See if we can simply do a shift without rounding
   104     bool needs_rounding = true;
   105     const Type *dt = phase->type(dividend);
   106     const TypeInt *dti = dt->isa_int();
   107     if (dti && dti->_lo >= 0) {
   108       // we don't need to round a positive dividend
   109       needs_rounding = false;
   110     } else if( dividend->Opcode() == Op_AndI ) {
   111       // An AND mask of sufficient size clears the low bits and
   112       // I can avoid rounding.
   113       const TypeInt *andconi_t = phase->type( dividend->in(2) )->isa_int();
   114       if( andconi_t && andconi_t->is_con() ) {
   115         jint andconi = andconi_t->get_con();
   116         if( andconi < 0 && is_power_of_2(-andconi) && (-andconi) >= d ) {
   117           if( (-andconi) == d ) // Remove AND if it clears bits which will be shifted
   118             dividend = dividend->in(1);
   119           needs_rounding = false;
   120         }
   121       }
   122     }
   124     // Add rounding to the shift to handle the sign bit
   125     int l = log2_intptr(d-1)+1;
   126     if (needs_rounding) {
   127       // Divide-by-power-of-2 can be made into a shift, but you have to do
   128       // more math for the rounding.  You need to add 0 for positive
   129       // numbers, and "i-1" for negative numbers.  Example: i=4, so the
   130       // shift is by 2.  You need to add 3 to negative dividends and 0 to
   131       // positive ones.  So (-7+3)>>2 becomes -1, (-4+3)>>2 becomes -1,
   132       // (-2+3)>>2 becomes 0, etc.
   134       // Compute 0 or -1, based on sign bit
   135       Node *sign = phase->transform(new (phase->C, 3) RShiftINode(dividend, phase->intcon(N - 1)));
   136       // Mask sign bit to the low sign bits
   137       Node *round = phase->transform(new (phase->C, 3) URShiftINode(sign, phase->intcon(N - l)));
   138       // Round up before shifting
   139       dividend = phase->transform(new (phase->C, 3) AddINode(dividend, round));
   140     }
   142     // Shift for division
   143     q = new (phase->C, 3) RShiftINode(dividend, phase->intcon(l));
   145     if (!d_pos) {
   146       q = new (phase->C, 3) SubINode(phase->intcon(0), phase->transform(q));
   147     }
   148   } else {
   149     // Attempt the jint constant divide -> multiply transform found in
   150     //   "Division by Invariant Integers using Multiplication"
   151     //     by Granlund and Montgomery
   152     // See also "Hacker's Delight", chapter 10 by Warren.
   154     jint magic_const;
   155     jint shift_const;
   156     if (magic_int_divide_constants(d, magic_const, shift_const)) {
   157       Node *magic = phase->longcon(magic_const);
   158       Node *dividend_long = phase->transform(new (phase->C, 2) ConvI2LNode(dividend));
   160       // Compute the high half of the dividend x magic multiplication
   161       Node *mul_hi = phase->transform(new (phase->C, 3) MulLNode(dividend_long, magic));
   163       if (magic_const < 0) {
   164         mul_hi = phase->transform(new (phase->C, 3) RShiftLNode(mul_hi, phase->intcon(N)));
   165         mul_hi = phase->transform(new (phase->C, 2) ConvL2INode(mul_hi));
   167         // The magic multiplier is too large for a 32 bit constant. We've adjusted
   168         // it down by 2^32, but have to add 1 dividend back in after the multiplication.
   169         // This handles the "overflow" case described by Granlund and Montgomery.
   170         mul_hi = phase->transform(new (phase->C, 3) AddINode(dividend, mul_hi));
   172         // Shift over the (adjusted) mulhi
   173         if (shift_const != 0) {
   174           mul_hi = phase->transform(new (phase->C, 3) RShiftINode(mul_hi, phase->intcon(shift_const)));
   175         }
   176       } else {
   177         // No add is required, we can merge the shifts together.
   178         mul_hi = phase->transform(new (phase->C, 3) RShiftLNode(mul_hi, phase->intcon(N + shift_const)));
   179         mul_hi = phase->transform(new (phase->C, 2) ConvL2INode(mul_hi));
   180       }
   182       // Get a 0 or -1 from the sign of the dividend.
   183       Node *addend0 = mul_hi;
   184       Node *addend1 = phase->transform(new (phase->C, 3) RShiftINode(dividend, phase->intcon(N-1)));
   186       // If the divisor is negative, swap the order of the input addends;
   187       // this has the effect of negating the quotient.
   188       if (!d_pos) {
   189         Node *temp = addend0; addend0 = addend1; addend1 = temp;
   190       }
   192       // Adjust the final quotient by subtracting -1 (adding 1)
   193       // from the mul_hi.
   194       q = new (phase->C, 3) SubINode(addend0, addend1);
   195     }
   196   }
   198   return q;
   199 }
   201 //---------------------magic_long_divide_constants-----------------------------
   202 // Compute magic multiplier and shift constant for converting a 64 bit divide
   203 // by constant into a multiply/shift/add series. Return false if calculations
   204 // fail.
   205 //
   206 // Borrowed almost verbatim from Hacker's Delight by Henry S. Warren, Jr. with
   207 // minor type name and parameter changes.  Adjusted to 64 bit word width.
   208 static bool magic_long_divide_constants(jlong d, jlong &M, jint &s) {
   209   int64_t p;
   210   uint64_t ad, anc, delta, q1, r1, q2, r2, t;
   211   const uint64_t two63 = 0x8000000000000000LL;     // 2**63.
   213   ad = ABS(d);
   214   if (d == 0 || d == 1) return false;
   215   t = two63 + ((uint64_t)d >> 63);
   216   anc = t - 1 - t%ad;     // Absolute value of nc.
   217   p = 63;                 // Init. p.
   218   q1 = two63/anc;         // Init. q1 = 2**p/|nc|.
   219   r1 = two63 - q1*anc;    // Init. r1 = rem(2**p, |nc|).
   220   q2 = two63/ad;          // Init. q2 = 2**p/|d|.
   221   r2 = two63 - q2*ad;     // Init. r2 = rem(2**p, |d|).
   222   do {
   223     p = p + 1;
   224     q1 = 2*q1;            // Update q1 = 2**p/|nc|.
   225     r1 = 2*r1;            // Update r1 = rem(2**p, |nc|).
   226     if (r1 >= anc) {      // (Must be an unsigned
   227       q1 = q1 + 1;        // comparison here).
   228       r1 = r1 - anc;
   229     }
   230     q2 = 2*q2;            // Update q2 = 2**p/|d|.
   231     r2 = 2*r2;            // Update r2 = rem(2**p, |d|).
   232     if (r2 >= ad) {       // (Must be an unsigned
   233       q2 = q2 + 1;        // comparison here).
   234       r2 = r2 - ad;
   235     }
   236     delta = ad - r2;
   237   } while (q1 < delta || (q1 == delta && r1 == 0));
   239   M = q2 + 1;
   240   if (d < 0) M = -M;      // Magic number and
   241   s = p - 64;             // shift amount to return.
   243   return true;
   244 }
   246 //---------------------long_by_long_mulhi--------------------------------------
   247 // Generate ideal node graph for upper half of a 64 bit x 64 bit multiplication
   248 static Node* long_by_long_mulhi(PhaseGVN* phase, Node* dividend, jlong magic_const) {
   249   // If the architecture supports a 64x64 mulhi, there is
   250   // no need to synthesize it in ideal nodes.
   251   if (Matcher::has_match_rule(Op_MulHiL)) {
   252     Node* v = phase->longcon(magic_const);
   253     return new (phase->C, 3) MulHiLNode(dividend, v);
   254   }
   256   // Taken from Hacker's Delight, Fig. 8-2. Multiply high signed.
   257   // (http://www.hackersdelight.org/HDcode/mulhs.c)
   258   //
   259   // int mulhs(int u, int v) {
   260   //    unsigned u0, v0, w0;
   261   //    int u1, v1, w1, w2, t;
   262   //
   263   //    u0 = u & 0xFFFF;  u1 = u >> 16;
   264   //    v0 = v & 0xFFFF;  v1 = v >> 16;
   265   //    w0 = u0*v0;
   266   //    t  = u1*v0 + (w0 >> 16);
   267   //    w1 = t & 0xFFFF;
   268   //    w2 = t >> 16;
   269   //    w1 = u0*v1 + w1;
   270   //    return u1*v1 + w2 + (w1 >> 16);
   271   // }
   272   //
   273   // Note: The version above is for 32x32 multiplications, while the
   274   // following inline comments are adapted to 64x64.
   276   const int N = 64;
   278   // u0 = u & 0xFFFFFFFF;  u1 = u >> 32;
   279   Node* u0 = phase->transform(new (phase->C, 3) AndLNode(dividend, phase->longcon(0xFFFFFFFF)));
   280   Node* u1 = phase->transform(new (phase->C, 3) RShiftLNode(dividend, phase->intcon(N / 2)));
   282   // v0 = v & 0xFFFFFFFF;  v1 = v >> 32;
   283   Node* v0 = phase->longcon(magic_const & 0xFFFFFFFF);
   284   Node* v1 = phase->longcon(magic_const >> (N / 2));
   286   // w0 = u0*v0;
   287   Node* w0 = phase->transform(new (phase->C, 3) MulLNode(u0, v0));
   289   // t = u1*v0 + (w0 >> 32);
   290   Node* u1v0 = phase->transform(new (phase->C, 3) MulLNode(u1, v0));
   291   Node* temp = phase->transform(new (phase->C, 3) URShiftLNode(w0, phase->intcon(N / 2)));
   292   Node* t    = phase->transform(new (phase->C, 3) AddLNode(u1v0, temp));
   294   // w1 = t & 0xFFFFFFFF;
   295   Node* w1 = new (phase->C, 3) AndLNode(t, phase->longcon(0xFFFFFFFF));
   297   // w2 = t >> 32;
   298   Node* w2 = new (phase->C, 3) RShiftLNode(t, phase->intcon(N / 2));
   300   // 6732154: Construct both w1 and w2 before transforming, so t
   301   // doesn't go dead prematurely.
   302   // 6837011: We need to transform w2 before w1 because the
   303   // transformation of w1 could return t.
   304   w2 = phase->transform(w2);
   305   w1 = phase->transform(w1);
   307   // w1 = u0*v1 + w1;
   308   Node* u0v1 = phase->transform(new (phase->C, 3) MulLNode(u0, v1));
   309   w1         = phase->transform(new (phase->C, 3) AddLNode(u0v1, w1));
   311   // return u1*v1 + w2 + (w1 >> 32);
   312   Node* u1v1  = phase->transform(new (phase->C, 3) MulLNode(u1, v1));
   313   Node* temp1 = phase->transform(new (phase->C, 3) AddLNode(u1v1, w2));
   314   Node* temp2 = phase->transform(new (phase->C, 3) RShiftLNode(w1, phase->intcon(N / 2)));
   316   return new (phase->C, 3) AddLNode(temp1, temp2);
   317 }
   320 //--------------------------transform_long_divide------------------------------
   321 // Convert a division by constant divisor into an alternate Ideal graph.
   322 // Return NULL if no transformation occurs.
   323 static Node *transform_long_divide( PhaseGVN *phase, Node *dividend, jlong divisor ) {
   324   // Check for invalid divisors
   325   assert( divisor != 0L && divisor != min_jlong,
   326           "bad divisor for transforming to long multiply" );
   328   bool d_pos = divisor >= 0;
   329   jlong d = d_pos ? divisor : -divisor;
   330   const int N = 64;
   332   // Result
   333   Node *q = NULL;
   335   if (d == 1) {
   336     // division by +/- 1
   337     if (!d_pos) {
   338       // Just negate the value
   339       q = new (phase->C, 3) SubLNode(phase->longcon(0), dividend);
   340     }
   341   } else if ( is_power_of_2_long(d) ) {
   343     // division by +/- a power of 2
   345     // See if we can simply do a shift without rounding
   346     bool needs_rounding = true;
   347     const Type *dt = phase->type(dividend);
   348     const TypeLong *dtl = dt->isa_long();
   350     if (dtl && dtl->_lo > 0) {
   351       // we don't need to round a positive dividend
   352       needs_rounding = false;
   353     } else if( dividend->Opcode() == Op_AndL ) {
   354       // An AND mask of sufficient size clears the low bits and
   355       // I can avoid rounding.
   356       const TypeLong *andconl_t = phase->type( dividend->in(2) )->isa_long();
   357       if( andconl_t && andconl_t->is_con() ) {
   358         jlong andconl = andconl_t->get_con();
   359         if( andconl < 0 && is_power_of_2_long(-andconl) && (-andconl) >= d ) {
   360           if( (-andconl) == d ) // Remove AND if it clears bits which will be shifted
   361             dividend = dividend->in(1);
   362           needs_rounding = false;
   363         }
   364       }
   365     }
   367     // Add rounding to the shift to handle the sign bit
   368     int l = log2_long(d-1)+1;
   369     if (needs_rounding) {
   370       // Divide-by-power-of-2 can be made into a shift, but you have to do
   371       // more math for the rounding.  You need to add 0 for positive
   372       // numbers, and "i-1" for negative numbers.  Example: i=4, so the
   373       // shift is by 2.  You need to add 3 to negative dividends and 0 to
   374       // positive ones.  So (-7+3)>>2 becomes -1, (-4+3)>>2 becomes -1,
   375       // (-2+3)>>2 becomes 0, etc.
   377       // Compute 0 or -1, based on sign bit
   378       Node *sign = phase->transform(new (phase->C, 3) RShiftLNode(dividend, phase->intcon(N - 1)));
   379       // Mask sign bit to the low sign bits
   380       Node *round = phase->transform(new (phase->C, 3) URShiftLNode(sign, phase->intcon(N - l)));
   381       // Round up before shifting
   382       dividend = phase->transform(new (phase->C, 3) AddLNode(dividend, round));
   383     }
   385     // Shift for division
   386     q = new (phase->C, 3) RShiftLNode(dividend, phase->intcon(l));
   388     if (!d_pos) {
   389       q = new (phase->C, 3) SubLNode(phase->longcon(0), phase->transform(q));
   390     }
   391   } else if ( !Matcher::use_asm_for_ldiv_by_con(d) ) { // Use hardware DIV instruction when
   392                                                        // it is faster than code generated below.
   393     // Attempt the jlong constant divide -> multiply transform found in
   394     //   "Division by Invariant Integers using Multiplication"
   395     //     by Granlund and Montgomery
   396     // See also "Hacker's Delight", chapter 10 by Warren.
   398     jlong magic_const;
   399     jint shift_const;
   400     if (magic_long_divide_constants(d, magic_const, shift_const)) {
   401       // Compute the high half of the dividend x magic multiplication
   402       Node *mul_hi = phase->transform(long_by_long_mulhi(phase, dividend, magic_const));
   404       // The high half of the 128-bit multiply is computed.
   405       if (magic_const < 0) {
   406         // The magic multiplier is too large for a 64 bit constant. We've adjusted
   407         // it down by 2^64, but have to add 1 dividend back in after the multiplication.
   408         // This handles the "overflow" case described by Granlund and Montgomery.
   409         mul_hi = phase->transform(new (phase->C, 3) AddLNode(dividend, mul_hi));
   410       }
   412       // Shift over the (adjusted) mulhi
   413       if (shift_const != 0) {
   414         mul_hi = phase->transform(new (phase->C, 3) RShiftLNode(mul_hi, phase->intcon(shift_const)));
   415       }
   417       // Get a 0 or -1 from the sign of the dividend.
   418       Node *addend0 = mul_hi;
   419       Node *addend1 = phase->transform(new (phase->C, 3) RShiftLNode(dividend, phase->intcon(N-1)));
   421       // If the divisor is negative, swap the order of the input addends;
   422       // this has the effect of negating the quotient.
   423       if (!d_pos) {
   424         Node *temp = addend0; addend0 = addend1; addend1 = temp;
   425       }
   427       // Adjust the final quotient by subtracting -1 (adding 1)
   428       // from the mul_hi.
   429       q = new (phase->C, 3) SubLNode(addend0, addend1);
   430     }
   431   }
   433   return q;
   434 }
   436 //=============================================================================
   437 //------------------------------Identity---------------------------------------
   438 // If the divisor is 1, we are an identity on the dividend.
   439 Node *DivINode::Identity( PhaseTransform *phase ) {
   440   return (phase->type( in(2) )->higher_equal(TypeInt::ONE)) ? in(1) : this;
   441 }
   443 //------------------------------Idealize---------------------------------------
   444 // Divides can be changed to multiplies and/or shifts
   445 Node *DivINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   446   if (in(0) && remove_dead_region(phase, can_reshape))  return this;
   447   // Don't bother trying to transform a dead node
   448   if( in(0) && in(0)->is_top() )  return NULL;
   450   const Type *t = phase->type( in(2) );
   451   if( t == TypeInt::ONE )       // Identity?
   452     return NULL;                // Skip it
   454   const TypeInt *ti = t->isa_int();
   455   if( !ti ) return NULL;
   456   if( !ti->is_con() ) return NULL;
   457   jint i = ti->get_con();       // Get divisor
   459   if (i == 0) return NULL;      // Dividing by zero constant does not idealize
   461   set_req(0,NULL);              // Dividing by a not-zero constant; no faulting
   463   // Dividing by MININT does not optimize as a power-of-2 shift.
   464   if( i == min_jint ) return NULL;
   466   return transform_int_divide( phase, in(1), i );
   467 }
   469 //------------------------------Value------------------------------------------
   470 // A DivINode divides its inputs.  The third input is a Control input, used to
   471 // prevent hoisting the divide above an unsafe test.
   472 const Type *DivINode::Value( PhaseTransform *phase ) const {
   473   // Either input is TOP ==> the result is TOP
   474   const Type *t1 = phase->type( in(1) );
   475   const Type *t2 = phase->type( in(2) );
   476   if( t1 == Type::TOP ) return Type::TOP;
   477   if( t2 == Type::TOP ) return Type::TOP;
   479   // x/x == 1 since we always generate the dynamic divisor check for 0.
   480   if( phase->eqv( in(1), in(2) ) )
   481     return TypeInt::ONE;
   483   // Either input is BOTTOM ==> the result is the local BOTTOM
   484   const Type *bot = bottom_type();
   485   if( (t1 == bot) || (t2 == bot) ||
   486       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
   487     return bot;
   489   // Divide the two numbers.  We approximate.
   490   // If divisor is a constant and not zero
   491   const TypeInt *i1 = t1->is_int();
   492   const TypeInt *i2 = t2->is_int();
   493   int widen = MAX2(i1->_widen, i2->_widen);
   495   if( i2->is_con() && i2->get_con() != 0 ) {
   496     int32 d = i2->get_con(); // Divisor
   497     jint lo, hi;
   498     if( d >= 0 ) {
   499       lo = i1->_lo/d;
   500       hi = i1->_hi/d;
   501     } else {
   502       if( d == -1 && i1->_lo == min_jint ) {
   503         // 'min_jint/-1' throws arithmetic exception during compilation
   504         lo = min_jint;
   505         // do not support holes, 'hi' must go to either min_jint or max_jint:
   506         // [min_jint, -10]/[-1,-1] ==> [min_jint] UNION [10,max_jint]
   507         hi = i1->_hi == min_jint ? min_jint : max_jint;
   508       } else {
   509         lo = i1->_hi/d;
   510         hi = i1->_lo/d;
   511       }
   512     }
   513     return TypeInt::make(lo, hi, widen);
   514   }
   516   // If the dividend is a constant
   517   if( i1->is_con() ) {
   518     int32 d = i1->get_con();
   519     if( d < 0 ) {
   520       if( d == min_jint ) {
   521         //  (-min_jint) == min_jint == (min_jint / -1)
   522         return TypeInt::make(min_jint, max_jint/2 + 1, widen);
   523       } else {
   524         return TypeInt::make(d, -d, widen);
   525       }
   526     }
   527     return TypeInt::make(-d, d, widen);
   528   }
   530   // Otherwise we give up all hope
   531   return TypeInt::INT;
   532 }
   535 //=============================================================================
   536 //------------------------------Identity---------------------------------------
   537 // If the divisor is 1, we are an identity on the dividend.
   538 Node *DivLNode::Identity( PhaseTransform *phase ) {
   539   return (phase->type( in(2) )->higher_equal(TypeLong::ONE)) ? in(1) : this;
   540 }
   542 //------------------------------Idealize---------------------------------------
   543 // Dividing by a power of 2 is a shift.
   544 Node *DivLNode::Ideal( PhaseGVN *phase, bool can_reshape) {
   545   if (in(0) && remove_dead_region(phase, can_reshape))  return this;
   546   // Don't bother trying to transform a dead node
   547   if( in(0) && in(0)->is_top() )  return NULL;
   549   const Type *t = phase->type( in(2) );
   550   if( t == TypeLong::ONE )      // Identity?
   551     return NULL;                // Skip it
   553   const TypeLong *tl = t->isa_long();
   554   if( !tl ) return NULL;
   555   if( !tl->is_con() ) return NULL;
   556   jlong l = tl->get_con();      // Get divisor
   558   if (l == 0) return NULL;      // Dividing by zero constant does not idealize
   560   set_req(0,NULL);              // Dividing by a not-zero constant; no faulting
   562   // Dividing by MINLONG does not optimize as a power-of-2 shift.
   563   if( l == min_jlong ) return NULL;
   565   return transform_long_divide( phase, in(1), l );
   566 }
   568 //------------------------------Value------------------------------------------
   569 // A DivLNode divides its inputs.  The third input is a Control input, used to
   570 // prevent hoisting the divide above an unsafe test.
   571 const Type *DivLNode::Value( PhaseTransform *phase ) const {
   572   // Either input is TOP ==> the result is TOP
   573   const Type *t1 = phase->type( in(1) );
   574   const Type *t2 = phase->type( in(2) );
   575   if( t1 == Type::TOP ) return Type::TOP;
   576   if( t2 == Type::TOP ) return Type::TOP;
   578   // x/x == 1 since we always generate the dynamic divisor check for 0.
   579   if( phase->eqv( in(1), in(2) ) )
   580     return TypeLong::ONE;
   582   // Either input is BOTTOM ==> the result is the local BOTTOM
   583   const Type *bot = bottom_type();
   584   if( (t1 == bot) || (t2 == bot) ||
   585       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
   586     return bot;
   588   // Divide the two numbers.  We approximate.
   589   // If divisor is a constant and not zero
   590   const TypeLong *i1 = t1->is_long();
   591   const TypeLong *i2 = t2->is_long();
   592   int widen = MAX2(i1->_widen, i2->_widen);
   594   if( i2->is_con() && i2->get_con() != 0 ) {
   595     jlong d = i2->get_con();    // Divisor
   596     jlong lo, hi;
   597     if( d >= 0 ) {
   598       lo = i1->_lo/d;
   599       hi = i1->_hi/d;
   600     } else {
   601       if( d == CONST64(-1) && i1->_lo == min_jlong ) {
   602         // 'min_jlong/-1' throws arithmetic exception during compilation
   603         lo = min_jlong;
   604         // do not support holes, 'hi' must go to either min_jlong or max_jlong:
   605         // [min_jlong, -10]/[-1,-1] ==> [min_jlong] UNION [10,max_jlong]
   606         hi = i1->_hi == min_jlong ? min_jlong : max_jlong;
   607       } else {
   608         lo = i1->_hi/d;
   609         hi = i1->_lo/d;
   610       }
   611     }
   612     return TypeLong::make(lo, hi, widen);
   613   }
   615   // If the dividend is a constant
   616   if( i1->is_con() ) {
   617     jlong d = i1->get_con();
   618     if( d < 0 ) {
   619       if( d == min_jlong ) {
   620         //  (-min_jlong) == min_jlong == (min_jlong / -1)
   621         return TypeLong::make(min_jlong, max_jlong/2 + 1, widen);
   622       } else {
   623         return TypeLong::make(d, -d, widen);
   624       }
   625     }
   626     return TypeLong::make(-d, d, widen);
   627   }
   629   // Otherwise we give up all hope
   630   return TypeLong::LONG;
   631 }
   634 //=============================================================================
   635 //------------------------------Value------------------------------------------
   636 // An DivFNode divides its inputs.  The third input is a Control input, used to
   637 // prevent hoisting the divide above an unsafe test.
   638 const Type *DivFNode::Value( PhaseTransform *phase ) const {
   639   // Either input is TOP ==> the result is TOP
   640   const Type *t1 = phase->type( in(1) );
   641   const Type *t2 = phase->type( in(2) );
   642   if( t1 == Type::TOP ) return Type::TOP;
   643   if( t2 == Type::TOP ) return Type::TOP;
   645   // Either input is BOTTOM ==> the result is the local BOTTOM
   646   const Type *bot = bottom_type();
   647   if( (t1 == bot) || (t2 == bot) ||
   648       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
   649     return bot;
   651   // x/x == 1, we ignore 0/0.
   652   // Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
   653   // Does not work for variables because of NaN's
   654   if( phase->eqv( in(1), in(2) ) && t1->base() == Type::FloatCon)
   655     if (!g_isnan(t1->getf()) && g_isfinite(t1->getf()) && t1->getf() != 0.0) // could be negative ZERO or NaN
   656       return TypeF::ONE;
   658   if( t2 == TypeF::ONE )
   659     return t1;
   661   // If divisor is a constant and not zero, divide them numbers
   662   if( t1->base() == Type::FloatCon &&
   663       t2->base() == Type::FloatCon &&
   664       t2->getf() != 0.0 ) // could be negative zero
   665     return TypeF::make( t1->getf()/t2->getf() );
   667   // If the dividend is a constant zero
   668   // Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
   669   // Test TypeF::ZERO is not sufficient as it could be negative zero
   671   if( t1 == TypeF::ZERO && !g_isnan(t2->getf()) && t2->getf() != 0.0 )
   672     return TypeF::ZERO;
   674   // Otherwise we give up all hope
   675   return Type::FLOAT;
   676 }
   678 //------------------------------isA_Copy---------------------------------------
   679 // Dividing by self is 1.
   680 // If the divisor is 1, we are an identity on the dividend.
   681 Node *DivFNode::Identity( PhaseTransform *phase ) {
   682   return (phase->type( in(2) ) == TypeF::ONE) ? in(1) : this;
   683 }
   686 //------------------------------Idealize---------------------------------------
   687 Node *DivFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   688   if (in(0) && remove_dead_region(phase, can_reshape))  return this;
   689   // Don't bother trying to transform a dead node
   690   if( in(0) && in(0)->is_top() )  return NULL;
   692   const Type *t2 = phase->type( in(2) );
   693   if( t2 == TypeF::ONE )         // Identity?
   694     return NULL;                // Skip it
   696   const TypeF *tf = t2->isa_float_constant();
   697   if( !tf ) return NULL;
   698   if( tf->base() != Type::FloatCon ) return NULL;
   700   // Check for out of range values
   701   if( tf->is_nan() || !tf->is_finite() ) return NULL;
   703   // Get the value
   704   float f = tf->getf();
   705   int exp;
   707   // Only for special case of dividing by a power of 2
   708   if( frexp((double)f, &exp) != 0.5 ) return NULL;
   710   // Limit the range of acceptable exponents
   711   if( exp < -126 || exp > 126 ) return NULL;
   713   // Compute the reciprocal
   714   float reciprocal = ((float)1.0) / f;
   716   assert( frexp((double)reciprocal, &exp) == 0.5, "reciprocal should be power of 2" );
   718   // return multiplication by the reciprocal
   719   return (new (phase->C, 3) MulFNode(in(1), phase->makecon(TypeF::make(reciprocal))));
   720 }
   722 //=============================================================================
   723 //------------------------------Value------------------------------------------
   724 // An DivDNode divides its inputs.  The third input is a Control input, used to
   725 // prevent hoisting the divide above an unsafe test.
   726 const Type *DivDNode::Value( PhaseTransform *phase ) const {
   727   // Either input is TOP ==> the result is TOP
   728   const Type *t1 = phase->type( in(1) );
   729   const Type *t2 = phase->type( in(2) );
   730   if( t1 == Type::TOP ) return Type::TOP;
   731   if( t2 == Type::TOP ) return Type::TOP;
   733   // Either input is BOTTOM ==> the result is the local BOTTOM
   734   const Type *bot = bottom_type();
   735   if( (t1 == bot) || (t2 == bot) ||
   736       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
   737     return bot;
   739   // x/x == 1, we ignore 0/0.
   740   // Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
   741   // Does not work for variables because of NaN's
   742   if( phase->eqv( in(1), in(2) ) && t1->base() == Type::DoubleCon)
   743     if (!g_isnan(t1->getd()) && g_isfinite(t1->getd()) && t1->getd() != 0.0) // could be negative ZERO or NaN
   744       return TypeD::ONE;
   746   if( t2 == TypeD::ONE )
   747     return t1;
   749 #if defined(IA32)
   750   if (!phase->C->method()->is_strict())
   751     // Can't trust native compilers to properly fold strict double
   752     // division with round-to-zero on this platform.
   753 #endif
   754     {
   755       // If divisor is a constant and not zero, divide them numbers
   756       if( t1->base() == Type::DoubleCon &&
   757           t2->base() == Type::DoubleCon &&
   758           t2->getd() != 0.0 ) // could be negative zero
   759         return TypeD::make( t1->getd()/t2->getd() );
   760     }
   762   // If the dividend is a constant zero
   763   // Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
   764   // Test TypeF::ZERO is not sufficient as it could be negative zero
   765   if( t1 == TypeD::ZERO && !g_isnan(t2->getd()) && t2->getd() != 0.0 )
   766     return TypeD::ZERO;
   768   // Otherwise we give up all hope
   769   return Type::DOUBLE;
   770 }
   773 //------------------------------isA_Copy---------------------------------------
   774 // Dividing by self is 1.
   775 // If the divisor is 1, we are an identity on the dividend.
   776 Node *DivDNode::Identity( PhaseTransform *phase ) {
   777   return (phase->type( in(2) ) == TypeD::ONE) ? in(1) : this;
   778 }
   780 //------------------------------Idealize---------------------------------------
   781 Node *DivDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   782   if (in(0) && remove_dead_region(phase, can_reshape))  return this;
   783   // Don't bother trying to transform a dead node
   784   if( in(0) && in(0)->is_top() )  return NULL;
   786   const Type *t2 = phase->type( in(2) );
   787   if( t2 == TypeD::ONE )         // Identity?
   788     return NULL;                // Skip it
   790   const TypeD *td = t2->isa_double_constant();
   791   if( !td ) return NULL;
   792   if( td->base() != Type::DoubleCon ) return NULL;
   794   // Check for out of range values
   795   if( td->is_nan() || !td->is_finite() ) return NULL;
   797   // Get the value
   798   double d = td->getd();
   799   int exp;
   801   // Only for special case of dividing by a power of 2
   802   if( frexp(d, &exp) != 0.5 ) return NULL;
   804   // Limit the range of acceptable exponents
   805   if( exp < -1021 || exp > 1022 ) return NULL;
   807   // Compute the reciprocal
   808   double reciprocal = 1.0 / d;
   810   assert( frexp(reciprocal, &exp) == 0.5, "reciprocal should be power of 2" );
   812   // return multiplication by the reciprocal
   813   return (new (phase->C, 3) MulDNode(in(1), phase->makecon(TypeD::make(reciprocal))));
   814 }
   816 //=============================================================================
   817 //------------------------------Idealize---------------------------------------
   818 Node *ModINode::Ideal(PhaseGVN *phase, bool can_reshape) {
   819   // Check for dead control input
   820   if( in(0) && remove_dead_region(phase, can_reshape) )  return this;
   821   // Don't bother trying to transform a dead node
   822   if( in(0) && in(0)->is_top() )  return NULL;
   824   // Get the modulus
   825   const Type *t = phase->type( in(2) );
   826   if( t == Type::TOP ) return NULL;
   827   const TypeInt *ti = t->is_int();
   829   // Check for useless control input
   830   // Check for excluding mod-zero case
   831   if( in(0) && (ti->_hi < 0 || ti->_lo > 0) ) {
   832     set_req(0, NULL);        // Yank control input
   833     return this;
   834   }
   836   // See if we are MOD'ing by 2^k or 2^k-1.
   837   if( !ti->is_con() ) return NULL;
   838   jint con = ti->get_con();
   840   Node *hook = new (phase->C, 1) Node(1);
   842   // First, special check for modulo 2^k-1
   843   if( con >= 0 && con < max_jint && is_power_of_2(con+1) ) {
   844     uint k = exact_log2(con+1);  // Extract k
   846     // Basic algorithm by David Detlefs.  See fastmod_int.java for gory details.
   847     static int unroll_factor[] = { 999, 999, 29, 14, 9, 7, 5, 4, 4, 3, 3, 2, 2, 2, 2, 2, 1 /*past here we assume 1 forever*/};
   848     int trip_count = 1;
   849     if( k < ARRAY_SIZE(unroll_factor))  trip_count = unroll_factor[k];
   851     // If the unroll factor is not too large, and if conditional moves are
   852     // ok, then use this case
   853     if( trip_count <= 5 && ConditionalMoveLimit != 0 ) {
   854       Node *x = in(1);            // Value being mod'd
   855       Node *divisor = in(2);      // Also is mask
   857       hook->init_req(0, x);       // Add a use to x to prevent him from dying
   858       // Generate code to reduce X rapidly to nearly 2^k-1.
   859       for( int i = 0; i < trip_count; i++ ) {
   860         Node *xl = phase->transform( new (phase->C, 3) AndINode(x,divisor) );
   861         Node *xh = phase->transform( new (phase->C, 3) RShiftINode(x,phase->intcon(k)) ); // Must be signed
   862         x = phase->transform( new (phase->C, 3) AddINode(xh,xl) );
   863         hook->set_req(0, x);
   864       }
   866       // Generate sign-fixup code.  Was original value positive?
   867       // int hack_res = (i >= 0) ? divisor : 1;
   868       Node *cmp1 = phase->transform( new (phase->C, 3) CmpINode( in(1), phase->intcon(0) ) );
   869       Node *bol1 = phase->transform( new (phase->C, 2) BoolNode( cmp1, BoolTest::ge ) );
   870       Node *cmov1= phase->transform( new (phase->C, 4) CMoveINode(bol1, phase->intcon(1), divisor, TypeInt::POS) );
   871       // if( x >= hack_res ) x -= divisor;
   872       Node *sub  = phase->transform( new (phase->C, 3) SubINode( x, divisor ) );
   873       Node *cmp2 = phase->transform( new (phase->C, 3) CmpINode( x, cmov1 ) );
   874       Node *bol2 = phase->transform( new (phase->C, 2) BoolNode( cmp2, BoolTest::ge ) );
   875       // Convention is to not transform the return value of an Ideal
   876       // since Ideal is expected to return a modified 'this' or a new node.
   877       Node *cmov2= new (phase->C, 4) CMoveINode(bol2, x, sub, TypeInt::INT);
   878       // cmov2 is now the mod
   880       // Now remove the bogus extra edges used to keep things alive
   881       if (can_reshape) {
   882         phase->is_IterGVN()->remove_dead_node(hook);
   883       } else {
   884         hook->set_req(0, NULL);   // Just yank bogus edge during Parse phase
   885       }
   886       return cmov2;
   887     }
   888   }
   890   // Fell thru, the unroll case is not appropriate. Transform the modulo
   891   // into a long multiply/int multiply/subtract case
   893   // Cannot handle mod 0, and min_jint isn't handled by the transform
   894   if( con == 0 || con == min_jint ) return NULL;
   896   // Get the absolute value of the constant; at this point, we can use this
   897   jint pos_con = (con >= 0) ? con : -con;
   899   // integer Mod 1 is always 0
   900   if( pos_con == 1 ) return new (phase->C, 1) ConINode(TypeInt::ZERO);
   902   int log2_con = -1;
   904   // If this is a power of two, they maybe we can mask it
   905   if( is_power_of_2(pos_con) ) {
   906     log2_con = log2_intptr((intptr_t)pos_con);
   908     const Type *dt = phase->type(in(1));
   909     const TypeInt *dti = dt->isa_int();
   911     // See if this can be masked, if the dividend is non-negative
   912     if( dti && dti->_lo >= 0 )
   913       return ( new (phase->C, 3) AndINode( in(1), phase->intcon( pos_con-1 ) ) );
   914   }
   916   // Save in(1) so that it cannot be changed or deleted
   917   hook->init_req(0, in(1));
   919   // Divide using the transform from DivI to MulL
   920   Node *result = transform_int_divide( phase, in(1), pos_con );
   921   if (result != NULL) {
   922     Node *divide = phase->transform(result);
   924     // Re-multiply, using a shift if this is a power of two
   925     Node *mult = NULL;
   927     if( log2_con >= 0 )
   928       mult = phase->transform( new (phase->C, 3) LShiftINode( divide, phase->intcon( log2_con ) ) );
   929     else
   930       mult = phase->transform( new (phase->C, 3) MulINode( divide, phase->intcon( pos_con ) ) );
   932     // Finally, subtract the multiplied divided value from the original
   933     result = new (phase->C, 3) SubINode( in(1), mult );
   934   }
   936   // Now remove the bogus extra edges used to keep things alive
   937   if (can_reshape) {
   938     phase->is_IterGVN()->remove_dead_node(hook);
   939   } else {
   940     hook->set_req(0, NULL);       // Just yank bogus edge during Parse phase
   941   }
   943   // return the value
   944   return result;
   945 }
   947 //------------------------------Value------------------------------------------
   948 const Type *ModINode::Value( PhaseTransform *phase ) const {
   949   // Either input is TOP ==> the result is TOP
   950   const Type *t1 = phase->type( in(1) );
   951   const Type *t2 = phase->type( in(2) );
   952   if( t1 == Type::TOP ) return Type::TOP;
   953   if( t2 == Type::TOP ) return Type::TOP;
   955   // We always generate the dynamic check for 0.
   956   // 0 MOD X is 0
   957   if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
   958   // X MOD X is 0
   959   if( phase->eqv( in(1), in(2) ) ) return TypeInt::ZERO;
   961   // Either input is BOTTOM ==> the result is the local BOTTOM
   962   const Type *bot = bottom_type();
   963   if( (t1 == bot) || (t2 == bot) ||
   964       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
   965     return bot;
   967   const TypeInt *i1 = t1->is_int();
   968   const TypeInt *i2 = t2->is_int();
   969   if( !i1->is_con() || !i2->is_con() ) {
   970     if( i1->_lo >= 0 && i2->_lo >= 0 )
   971       return TypeInt::POS;
   972     // If both numbers are not constants, we know little.
   973     return TypeInt::INT;
   974   }
   975   // Mod by zero?  Throw exception at runtime!
   976   if( !i2->get_con() ) return TypeInt::POS;
   978   // We must be modulo'ing 2 float constants.
   979   // Check for min_jint % '-1', result is defined to be '0'.
   980   if( i1->get_con() == min_jint && i2->get_con() == -1 )
   981     return TypeInt::ZERO;
   983   return TypeInt::make( i1->get_con() % i2->get_con() );
   984 }
   987 //=============================================================================
   988 //------------------------------Idealize---------------------------------------
   989 Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   990   // Check for dead control input
   991   if( in(0) && remove_dead_region(phase, can_reshape) )  return this;
   992   // Don't bother trying to transform a dead node
   993   if( in(0) && in(0)->is_top() )  return NULL;
   995   // Get the modulus
   996   const Type *t = phase->type( in(2) );
   997   if( t == Type::TOP ) return NULL;
   998   const TypeLong *tl = t->is_long();
  1000   // Check for useless control input
  1001   // Check for excluding mod-zero case
  1002   if( in(0) && (tl->_hi < 0 || tl->_lo > 0) ) {
  1003     set_req(0, NULL);        // Yank control input
  1004     return this;
  1007   // See if we are MOD'ing by 2^k or 2^k-1.
  1008   if( !tl->is_con() ) return NULL;
  1009   jlong con = tl->get_con();
  1011   Node *hook = new (phase->C, 1) Node(1);
  1013   // Expand mod
  1014   if( con >= 0 && con < max_jlong && is_power_of_2_long(con+1) ) {
  1015     uint k = exact_log2_long(con+1);  // Extract k
  1017     // Basic algorithm by David Detlefs.  See fastmod_long.java for gory details.
  1018     // Used to help a popular random number generator which does a long-mod
  1019     // of 2^31-1 and shows up in SpecJBB and SciMark.
  1020     static int unroll_factor[] = { 999, 999, 61, 30, 20, 15, 12, 10, 8, 7, 6, 6, 5, 5, 4, 4, 4, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1 /*past here we assume 1 forever*/};
  1021     int trip_count = 1;
  1022     if( k < ARRAY_SIZE(unroll_factor)) trip_count = unroll_factor[k];
  1024     // If the unroll factor is not too large, and if conditional moves are
  1025     // ok, then use this case
  1026     if( trip_count <= 5 && ConditionalMoveLimit != 0 ) {
  1027       Node *x = in(1);            // Value being mod'd
  1028       Node *divisor = in(2);      // Also is mask
  1030       hook->init_req(0, x);       // Add a use to x to prevent him from dying
  1031       // Generate code to reduce X rapidly to nearly 2^k-1.
  1032       for( int i = 0; i < trip_count; i++ ) {
  1033         Node *xl = phase->transform( new (phase->C, 3) AndLNode(x,divisor) );
  1034         Node *xh = phase->transform( new (phase->C, 3) RShiftLNode(x,phase->intcon(k)) ); // Must be signed
  1035         x = phase->transform( new (phase->C, 3) AddLNode(xh,xl) );
  1036         hook->set_req(0, x);    // Add a use to x to prevent him from dying
  1039       // Generate sign-fixup code.  Was original value positive?
  1040       // long hack_res = (i >= 0) ? divisor : CONST64(1);
  1041       Node *cmp1 = phase->transform( new (phase->C, 3) CmpLNode( in(1), phase->longcon(0) ) );
  1042       Node *bol1 = phase->transform( new (phase->C, 2) BoolNode( cmp1, BoolTest::ge ) );
  1043       Node *cmov1= phase->transform( new (phase->C, 4) CMoveLNode(bol1, phase->longcon(1), divisor, TypeLong::LONG) );
  1044       // if( x >= hack_res ) x -= divisor;
  1045       Node *sub  = phase->transform( new (phase->C, 3) SubLNode( x, divisor ) );
  1046       Node *cmp2 = phase->transform( new (phase->C, 3) CmpLNode( x, cmov1 ) );
  1047       Node *bol2 = phase->transform( new (phase->C, 2) BoolNode( cmp2, BoolTest::ge ) );
  1048       // Convention is to not transform the return value of an Ideal
  1049       // since Ideal is expected to return a modified 'this' or a new node.
  1050       Node *cmov2= new (phase->C, 4) CMoveLNode(bol2, x, sub, TypeLong::LONG);
  1051       // cmov2 is now the mod
  1053       // Now remove the bogus extra edges used to keep things alive
  1054       if (can_reshape) {
  1055         phase->is_IterGVN()->remove_dead_node(hook);
  1056       } else {
  1057         hook->set_req(0, NULL);   // Just yank bogus edge during Parse phase
  1059       return cmov2;
  1063   // Fell thru, the unroll case is not appropriate. Transform the modulo
  1064   // into a long multiply/int multiply/subtract case
  1066   // Cannot handle mod 0, and min_jlong isn't handled by the transform
  1067   if( con == 0 || con == min_jlong ) return NULL;
  1069   // Get the absolute value of the constant; at this point, we can use this
  1070   jlong pos_con = (con >= 0) ? con : -con;
  1072   // integer Mod 1 is always 0
  1073   if( pos_con == 1 ) return new (phase->C, 1) ConLNode(TypeLong::ZERO);
  1075   int log2_con = -1;
  1077   // If this is a power of two, then maybe we can mask it
  1078   if( is_power_of_2_long(pos_con) ) {
  1079     log2_con = exact_log2_long(pos_con);
  1081     const Type *dt = phase->type(in(1));
  1082     const TypeLong *dtl = dt->isa_long();
  1084     // See if this can be masked, if the dividend is non-negative
  1085     if( dtl && dtl->_lo >= 0 )
  1086       return ( new (phase->C, 3) AndLNode( in(1), phase->longcon( pos_con-1 ) ) );
  1089   // Save in(1) so that it cannot be changed or deleted
  1090   hook->init_req(0, in(1));
  1092   // Divide using the transform from DivL to MulL
  1093   Node *result = transform_long_divide( phase, in(1), pos_con );
  1094   if (result != NULL) {
  1095     Node *divide = phase->transform(result);
  1097     // Re-multiply, using a shift if this is a power of two
  1098     Node *mult = NULL;
  1100     if( log2_con >= 0 )
  1101       mult = phase->transform( new (phase->C, 3) LShiftLNode( divide, phase->intcon( log2_con ) ) );
  1102     else
  1103       mult = phase->transform( new (phase->C, 3) MulLNode( divide, phase->longcon( pos_con ) ) );
  1105     // Finally, subtract the multiplied divided value from the original
  1106     result = new (phase->C, 3) SubLNode( in(1), mult );
  1109   // Now remove the bogus extra edges used to keep things alive
  1110   if (can_reshape) {
  1111     phase->is_IterGVN()->remove_dead_node(hook);
  1112   } else {
  1113     hook->set_req(0, NULL);       // Just yank bogus edge during Parse phase
  1116   // return the value
  1117   return result;
  1120 //------------------------------Value------------------------------------------
  1121 const Type *ModLNode::Value( PhaseTransform *phase ) const {
  1122   // Either input is TOP ==> the result is TOP
  1123   const Type *t1 = phase->type( in(1) );
  1124   const Type *t2 = phase->type( in(2) );
  1125   if( t1 == Type::TOP ) return Type::TOP;
  1126   if( t2 == Type::TOP ) return Type::TOP;
  1128   // We always generate the dynamic check for 0.
  1129   // 0 MOD X is 0
  1130   if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
  1131   // X MOD X is 0
  1132   if( phase->eqv( in(1), in(2) ) ) return TypeLong::ZERO;
  1134   // Either input is BOTTOM ==> the result is the local BOTTOM
  1135   const Type *bot = bottom_type();
  1136   if( (t1 == bot) || (t2 == bot) ||
  1137       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
  1138     return bot;
  1140   const TypeLong *i1 = t1->is_long();
  1141   const TypeLong *i2 = t2->is_long();
  1142   if( !i1->is_con() || !i2->is_con() ) {
  1143     if( i1->_lo >= CONST64(0) && i2->_lo >= CONST64(0) )
  1144       return TypeLong::POS;
  1145     // If both numbers are not constants, we know little.
  1146     return TypeLong::LONG;
  1148   // Mod by zero?  Throw exception at runtime!
  1149   if( !i2->get_con() ) return TypeLong::POS;
  1151   // We must be modulo'ing 2 float constants.
  1152   // Check for min_jint % '-1', result is defined to be '0'.
  1153   if( i1->get_con() == min_jlong && i2->get_con() == -1 )
  1154     return TypeLong::ZERO;
  1156   return TypeLong::make( i1->get_con() % i2->get_con() );
  1160 //=============================================================================
  1161 //------------------------------Value------------------------------------------
  1162 const Type *ModFNode::Value( PhaseTransform *phase ) const {
  1163   // Either input is TOP ==> the result is TOP
  1164   const Type *t1 = phase->type( in(1) );
  1165   const Type *t2 = phase->type( in(2) );
  1166   if( t1 == Type::TOP ) return Type::TOP;
  1167   if( t2 == Type::TOP ) return Type::TOP;
  1169   // Either input is BOTTOM ==> the result is the local BOTTOM
  1170   const Type *bot = bottom_type();
  1171   if( (t1 == bot) || (t2 == bot) ||
  1172       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
  1173     return bot;
  1175   // If either number is not a constant, we know nothing.
  1176   if ((t1->base() != Type::FloatCon) || (t2->base() != Type::FloatCon)) {
  1177     return Type::FLOAT;         // note: x%x can be either NaN or 0
  1180   float f1 = t1->getf();
  1181   float f2 = t2->getf();
  1182   jint  x1 = jint_cast(f1);     // note:  *(int*)&f1, not just (int)f1
  1183   jint  x2 = jint_cast(f2);
  1185   // If either is a NaN, return an input NaN
  1186   if (g_isnan(f1))    return t1;
  1187   if (g_isnan(f2))    return t2;
  1189   // If an operand is infinity or the divisor is +/- zero, punt.
  1190   if (!g_isfinite(f1) || !g_isfinite(f2) || x2 == 0 || x2 == min_jint)
  1191     return Type::FLOAT;
  1193   // We must be modulo'ing 2 float constants.
  1194   // Make sure that the sign of the fmod is equal to the sign of the dividend
  1195   jint xr = jint_cast(fmod(f1, f2));
  1196   if ((x1 ^ xr) < 0) {
  1197     xr ^= min_jint;
  1200   return TypeF::make(jfloat_cast(xr));
  1204 //=============================================================================
  1205 //------------------------------Value------------------------------------------
  1206 const Type *ModDNode::Value( PhaseTransform *phase ) const {
  1207   // Either input is TOP ==> the result is TOP
  1208   const Type *t1 = phase->type( in(1) );
  1209   const Type *t2 = phase->type( in(2) );
  1210   if( t1 == Type::TOP ) return Type::TOP;
  1211   if( t2 == Type::TOP ) return Type::TOP;
  1213   // Either input is BOTTOM ==> the result is the local BOTTOM
  1214   const Type *bot = bottom_type();
  1215   if( (t1 == bot) || (t2 == bot) ||
  1216       (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
  1217     return bot;
  1219   // If either number is not a constant, we know nothing.
  1220   if ((t1->base() != Type::DoubleCon) || (t2->base() != Type::DoubleCon)) {
  1221     return Type::DOUBLE;        // note: x%x can be either NaN or 0
  1224   double f1 = t1->getd();
  1225   double f2 = t2->getd();
  1226   jlong  x1 = jlong_cast(f1);   // note:  *(long*)&f1, not just (long)f1
  1227   jlong  x2 = jlong_cast(f2);
  1229   // If either is a NaN, return an input NaN
  1230   if (g_isnan(f1))    return t1;
  1231   if (g_isnan(f2))    return t2;
  1233   // If an operand is infinity or the divisor is +/- zero, punt.
  1234   if (!g_isfinite(f1) || !g_isfinite(f2) || x2 == 0 || x2 == min_jlong)
  1235     return Type::DOUBLE;
  1237   // We must be modulo'ing 2 double constants.
  1238   // Make sure that the sign of the fmod is equal to the sign of the dividend
  1239   jlong xr = jlong_cast(fmod(f1, f2));
  1240   if ((x1 ^ xr) < 0) {
  1241     xr ^= min_jlong;
  1244   return TypeD::make(jdouble_cast(xr));
  1247 //=============================================================================
  1249 DivModNode::DivModNode( Node *c, Node *dividend, Node *divisor ) : MultiNode(3) {
  1250   init_req(0, c);
  1251   init_req(1, dividend);
  1252   init_req(2, divisor);
  1255 //------------------------------make------------------------------------------
  1256 DivModINode* DivModINode::make(Compile* C, Node* div_or_mod) {
  1257   Node* n = div_or_mod;
  1258   assert(n->Opcode() == Op_DivI || n->Opcode() == Op_ModI,
  1259          "only div or mod input pattern accepted");
  1261   DivModINode* divmod = new (C, 3) DivModINode(n->in(0), n->in(1), n->in(2));
  1262   Node*        dproj  = new (C, 1) ProjNode(divmod, DivModNode::div_proj_num);
  1263   Node*        mproj  = new (C, 1) ProjNode(divmod, DivModNode::mod_proj_num);
  1264   return divmod;
  1267 //------------------------------make------------------------------------------
  1268 DivModLNode* DivModLNode::make(Compile* C, Node* div_or_mod) {
  1269   Node* n = div_or_mod;
  1270   assert(n->Opcode() == Op_DivL || n->Opcode() == Op_ModL,
  1271          "only div or mod input pattern accepted");
  1273   DivModLNode* divmod = new (C, 3) DivModLNode(n->in(0), n->in(1), n->in(2));
  1274   Node*        dproj  = new (C, 1) ProjNode(divmod, DivModNode::div_proj_num);
  1275   Node*        mproj  = new (C, 1) ProjNode(divmod, DivModNode::mod_proj_num);
  1276   return divmod;
  1279 //------------------------------match------------------------------------------
  1280 // return result(s) along with their RegMask info
  1281 Node *DivModINode::match( const ProjNode *proj, const Matcher *match ) {
  1282   uint ideal_reg = proj->ideal_reg();
  1283   RegMask rm;
  1284   if (proj->_con == div_proj_num) {
  1285     rm = match->divI_proj_mask();
  1286   } else {
  1287     assert(proj->_con == mod_proj_num, "must be div or mod projection");
  1288     rm = match->modI_proj_mask();
  1290   return new (match->C, 1)MachProjNode(this, proj->_con, rm, ideal_reg);
  1294 //------------------------------match------------------------------------------
  1295 // return result(s) along with their RegMask info
  1296 Node *DivModLNode::match( const ProjNode *proj, const Matcher *match ) {
  1297   uint ideal_reg = proj->ideal_reg();
  1298   RegMask rm;
  1299   if (proj->_con == div_proj_num) {
  1300     rm = match->divL_proj_mask();
  1301   } else {
  1302     assert(proj->_con == mod_proj_num, "must be div or mod projection");
  1303     rm = match->modL_proj_mask();
  1305   return new (match->C, 1)MachProjNode(this, proj->_con, rm, ideal_reg);

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