1.1 --- a/src/share/vm/opto/addnode.cpp Wed Sep 23 16:26:20 2020 +0300
1.2 +++ b/src/share/vm/opto/addnode.cpp Wed May 13 15:59:17 2020 +0200
1.3 @@ -844,6 +844,14 @@
1.4 return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
1.5 }
1.6
1.7 +// Check if addition of an integer with type 't' and a constant 'c' can overflow
1.8 +static bool can_overflow(const TypeInt* t, jint c) {
1.9 + jint t_lo = t->_lo;
1.10 + jint t_hi = t->_hi;
1.11 + return ((c < 0 && (java_add(t_lo, c) > t_lo)) ||
1.12 + (c > 0 && (java_add(t_hi, c) < t_hi)));
1.13 +}
1.14 +
1.15 //=============================================================================
1.16 //------------------------------Idealize---------------------------------------
1.17 // MINs show up in range-check loop limit calculations. Look for
1.18 @@ -866,7 +874,7 @@
1.19
1.20 // Get left input & constant
1.21 Node *x = l;
1.22 - int x_off = 0;
1.23 + jint x_off = 0;
1.24 if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
1.25 x->in(2)->is_Con() ) {
1.26 const Type *t = x->in(2)->bottom_type();
1.27 @@ -877,7 +885,7 @@
1.28
1.29 // Scan a right-spline-tree for MINs
1.30 Node *y = r;
1.31 - int y_off = 0;
1.32 + jint y_off = 0;
1.33 // Check final part of MIN tree
1.34 if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
1.35 y->in(2)->is_Con() ) {
1.36 @@ -891,6 +899,7 @@
1.37 return this;
1.38 }
1.39
1.40 + const TypeInt* tx = phase->type(x)->isa_int();
1.41
1.42 if( r->Opcode() == Op_MinI ) {
1.43 assert( r != r->in(2), "dead loop in MinINode::Ideal" );
1.44 @@ -907,18 +916,23 @@
1.45 if( x->_idx > y->_idx )
1.46 return new (phase->C) MinINode(r->in(1),phase->transform(new (phase->C) MinINode(l,r->in(2))));
1.47
1.48 - // See if covers: MIN2(x+c0,MIN2(y+c1,z))
1.49 - if( !phase->eqv(x,y) ) return NULL;
1.50 - // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into
1.51 - // MIN2(x+c0 or x+c1 which less, z).
1.52 - return new (phase->C) MinINode(phase->transform(new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));
1.53 + // Transform MIN2(x + c0, MIN2(x + c1, z)) into MIN2(x + MIN2(c0, c1), z)
1.54 + // if x == y and the additions can't overflow.
1.55 + if (phase->eqv(x,y) &&
1.56 + !can_overflow(tx, x_off) &&
1.57 + !can_overflow(tx, y_off)) {
1.58 + return new (phase->C) MinINode(phase->transform(new (phase->C) AddINode(x, phase->intcon(MIN2(x_off, y_off)))), r->in(2));
1.59 + }
1.60 } else {
1.61 - // See if covers: MIN2(x+c0,y+c1)
1.62 - if( !phase->eqv(x,y) ) return NULL;
1.63 - // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.
1.64 - return new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)));
1.65 + // Transform MIN2(x + c0, y + c1) into x + MIN2(c0, c1)
1.66 + // if x == y and the additions can't overflow.
1.67 + if (phase->eqv(x,y) &&
1.68 + !can_overflow(tx, x_off) &&
1.69 + !can_overflow(tx, y_off)) {
1.70 + return new (phase->C) AddINode(x,phase->intcon(MIN2(x_off,y_off)));
1.71 + }
1.72 }
1.73 -
1.74 + return NULL;
1.75 }
1.76
1.77 //------------------------------add_ring---------------------------------------
