1.1 --- a/src/share/vm/opto/ifnode.cpp Wed Dec 05 09:00:00 2007 -0800
1.2 +++ b/src/share/vm/opto/ifnode.cpp Wed Dec 05 09:01:00 2007 -0800
1.3 @@ -543,6 +543,159 @@
1.4 return NULL; // Dead loop? Or hit root?
1.5 }
1.6
1.7 +
1.8 +//------------------------------filtered_int_type--------------------------------
1.9 +// Return a possibly more restrictive type for val based on condition control flow for an if
1.10 +const TypeInt* IfNode::filtered_int_type(PhaseGVN* gvn, Node *val, Node* if_proj) {
1.11 + assert(if_proj &&
1.12 + (if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection");
1.13 + if (if_proj->in(0) && if_proj->in(0)->is_If()) {
1.14 + IfNode* iff = if_proj->in(0)->as_If();
1.15 + if (iff->in(1) && iff->in(1)->is_Bool()) {
1.16 + BoolNode* bol = iff->in(1)->as_Bool();
1.17 + if (bol->in(1) && bol->in(1)->is_Cmp()) {
1.18 + const CmpNode* cmp = bol->in(1)->as_Cmp();
1.19 + if (cmp->in(1) == val) {
1.20 + const TypeInt* cmp2_t = gvn->type(cmp->in(2))->isa_int();
1.21 + if (cmp2_t != NULL) {
1.22 + jint lo = cmp2_t->_lo;
1.23 + jint hi = cmp2_t->_hi;
1.24 + BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate();
1.25 + switch (msk) {
1.26 + case BoolTest::ne:
1.27 + // Can't refine type
1.28 + return NULL;
1.29 + case BoolTest::eq:
1.30 + return cmp2_t;
1.31 + case BoolTest::lt:
1.32 + lo = TypeInt::INT->_lo;
1.33 + if (hi - 1 < hi) {
1.34 + hi = hi - 1;
1.35 + }
1.36 + break;
1.37 + case BoolTest::le:
1.38 + lo = TypeInt::INT->_lo;
1.39 + break;
1.40 + case BoolTest::gt:
1.41 + if (lo + 1 > lo) {
1.42 + lo = lo + 1;
1.43 + }
1.44 + hi = TypeInt::INT->_hi;
1.45 + break;
1.46 + case BoolTest::ge:
1.47 + // lo unchanged
1.48 + hi = TypeInt::INT->_hi;
1.49 + break;
1.50 + }
1.51 + const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen);
1.52 + return rtn_t;
1.53 + }
1.54 + }
1.55 + }
1.56 + }
1.57 + }
1.58 + return NULL;
1.59 +}
1.60 +
1.61 +//------------------------------fold_compares----------------------------
1.62 +// See if a pair of CmpIs can be converted into a CmpU. In some cases
1.63 +// the direction of this if is determined by the preciding if so it
1.64 +// can be eliminate entirely. Given an if testing (CmpI n c) check
1.65 +// for an immediately control dependent if that is testing (CmpI n c2)
1.66 +// and has one projection leading to this if and the other projection
1.67 +// leading to a region that merges one of this ifs control
1.68 +// projections.
1.69 +//
1.70 +// If
1.71 +// / |
1.72 +// / |
1.73 +// / |
1.74 +// If |
1.75 +// /\ |
1.76 +// / \ |
1.77 +// / \ |
1.78 +// / Region
1.79 +//
1.80 +Node* IfNode::fold_compares(PhaseGVN* phase) {
1.81 + if (!EliminateAutoBox || Opcode() != Op_If) return NULL;
1.82 +
1.83 + Node* this_cmp = in(1)->in(1);
1.84 + if (this_cmp != NULL && this_cmp->Opcode() == Op_CmpI &&
1.85 + this_cmp->in(2)->is_Con() && this_cmp->in(2) != phase->C->top()) {
1.86 + Node* ctrl = in(0);
1.87 + BoolNode* this_bool = in(1)->as_Bool();
1.88 + Node* n = this_cmp->in(1);
1.89 + int hi = this_cmp->in(2)->get_int();
1.90 + if (ctrl != NULL && ctrl->is_Proj() && ctrl->outcnt() == 1 &&
1.91 + ctrl->in(0)->is_If() &&
1.92 + ctrl->in(0)->outcnt() == 2 &&
1.93 + ctrl->in(0)->in(1)->is_Bool() &&
1.94 + ctrl->in(0)->in(1)->in(1)->Opcode() == Op_CmpI &&
1.95 + ctrl->in(0)->in(1)->in(1)->in(2)->is_Con() &&
1.96 + ctrl->in(0)->in(1)->in(1)->in(1) == n) {
1.97 + IfNode* dom_iff = ctrl->in(0)->as_If();
1.98 + Node* otherproj = dom_iff->proj_out(!ctrl->as_Proj()->_con);
1.99 + if (otherproj->outcnt() == 1 && otherproj->unique_out()->is_Region() &&
1.100 + this_bool->_test._test != BoolTest::ne && this_bool->_test._test != BoolTest::eq) {
1.101 + // Identify which proj goes to the region and which continues on
1.102 + RegionNode* region = otherproj->unique_out()->as_Region();
1.103 + Node* success = NULL;
1.104 + Node* fail = NULL;
1.105 + for (int i = 0; i < 2; i++) {
1.106 + Node* proj = proj_out(i);
1.107 + if (success == NULL && proj->outcnt() == 1 && proj->unique_out() == region) {
1.108 + success = proj;
1.109 + } else if (fail == NULL) {
1.110 + fail = proj;
1.111 + } else {
1.112 + success = fail = NULL;
1.113 + }
1.114 + }
1.115 + if (success != NULL && fail != NULL && !region->has_phi()) {
1.116 + int lo = dom_iff->in(1)->in(1)->in(2)->get_int();
1.117 + BoolNode* dom_bool = dom_iff->in(1)->as_Bool();
1.118 + Node* dom_cmp = dom_bool->in(1);
1.119 + const TypeInt* failtype = filtered_int_type(phase, n, ctrl);
1.120 + if (failtype != NULL) {
1.121 + const TypeInt* type2 = filtered_int_type(phase, n, fail);
1.122 + if (type2 != NULL) {
1.123 + failtype = failtype->join(type2)->is_int();
1.124 + } else {
1.125 + failtype = NULL;
1.126 + }
1.127 + }
1.128 +
1.129 + if (failtype != NULL &&
1.130 + dom_bool->_test._test != BoolTest::ne && dom_bool->_test._test != BoolTest::eq) {
1.131 + int bound = failtype->_hi - failtype->_lo + 1;
1.132 + if (failtype->_hi != max_jint && failtype->_lo != min_jint && bound > 1) {
1.133 + // Merge the two compares into a single unsigned compare by building (CmpU (n - lo) hi)
1.134 + BoolTest::mask cond = fail->as_Proj()->_con ? BoolTest::lt : BoolTest::ge;
1.135 + Node* adjusted = phase->transform(new (phase->C, 3) SubINode(n, phase->intcon(failtype->_lo)));
1.136 + Node* newcmp = phase->transform(new (phase->C, 3) CmpUNode(adjusted, phase->intcon(bound)));
1.137 + Node* newbool = phase->transform(new (phase->C, 2) BoolNode(newcmp, cond));
1.138 + phase->hash_delete(dom_iff);
1.139 + dom_iff->set_req(1, phase->intcon(ctrl->as_Proj()->_con));
1.140 + phase->is_IterGVN()->_worklist.push(dom_iff);
1.141 + phase->hash_delete(this);
1.142 + set_req(1, newbool);
1.143 + return this;
1.144 + }
1.145 + if (failtype->_lo > failtype->_hi) {
1.146 + // previous if determines the result of this if so
1.147 + // replace Bool with constant
1.148 + phase->hash_delete(this);
1.149 + set_req(1, phase->intcon(success->as_Proj()->_con));
1.150 + return this;
1.151 + }
1.152 + }
1.153 + }
1.154 + }
1.155 + }
1.156 + }
1.157 + return NULL;
1.158 +}
1.159 +
1.160 //------------------------------remove_useless_bool----------------------------
1.161 // Check for people making a useless boolean: things like
1.162 // if( (x < y ? true : false) ) { ... }
1.163 @@ -744,6 +897,11 @@
1.164 // Normal equivalent-test check.
1.165 if( !dom ) return NULL; // Dead loop?
1.166
1.167 + Node* result = fold_compares(phase);
1.168 + if (result != NULL) {
1.169 + return result;
1.170 + }
1.171 +
1.172 // Search up the dominator tree for an If with an identical test
1.173 while( dom->Opcode() != op || // Not same opcode?
1.174 dom->in(1) != in(1) || // Not same input 1?
