Bias commutative single-use register inputs and support lea adds

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 371c16c8e6dab1daab58c074b95f82178f6ee70b..6768f393d229cca21381650da854247c677ac0ba 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1392,8 +1392,10 @@ LInstruction* LChunkBuilder::DoBitwise(HBitwise* instr) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
 
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-    LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
+    LOperand* left =
+        UseRegisterAtStart(instr->BetterCandidateForRegisterOperand());
+    LOperand* right =
+        UseOrConstantAtStart(instr->WorseCandidateForRegisterOperand());
     return DefineSameAsFirst(new(zone()) LBitI(left, right));
   } else {
     ASSERT(instr->representation().IsTagged());
@@ -1560,8 +1562,10 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-    LOperand* right = UseOrConstant(instr->MostConstantOperand());
+    LOperand* left =
+        UseRegisterAtStart(instr->BetterCandidateForRegisterOperand());
+    LOperand* right =
+        UseOrConstant(instr->WorseCandidateForRegisterOperand());
     LOperand* temp = NULL;
     if (instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
       temp = TempRegister();
@@ -1604,13 +1608,25 @@ LInstruction* LChunkBuilder::DoSub(HSub* instr) {
 
 LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
   if (instr->representation().IsInteger32()) {
+    bool use_lea = LAddI::UseLea(instr);
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-    LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
+    LOperand* left =
+        UseRegisterAtStart(instr->BetterCandidateForRegisterOperand());
+    HValue* worse_candidate = instr->WorseCandidateForRegisterOperand();
+    LOperand* right = use_lea
+        ? UseRegisterOrConstantAtStart(worse_candidate)
+        : UseOrConstantAtStart(worse_candidate);
     LAddI* add = new(zone()) LAddI(left, right);
-    LInstruction* result = DefineSameAsFirst(add);
-    if (instr->CheckFlag(HValue::kCanOverflow)) {
+    bool can_overflow = instr->CheckFlag(HValue::kCanOverflow);
+    // Check to see if it would be advantageous to use

[Jakob Kummerow, 2013/05/03 09:01:37]

nit: use what?

+    LInstruction* result = NULL;
+    if (use_lea) {
+      result = DefineAsRegister(add);
+    } else {
+      result = DefineSameAsFirst(add);
+    }
+    if (can_overflow) {
       result = AssignEnvironment(result);
     }
     return result;
@@ -1629,8 +1645,8 @@ LInstruction* LChunkBuilder::DoMathMinMax(HMathMinMax* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    left = UseRegisterAtStart(instr->LeastConstantOperand());
-    right = UseOrConstantAtStart(instr->MostConstantOperand());
+    left = UseRegisterAtStart(instr->BetterCandidateForRegisterOperand());
+    right = UseOrConstantAtStart(instr->WorseCandidateForRegisterOperand());
   } else {
     ASSERT(instr->representation().IsDouble());
     ASSERT(instr->left()->representation().IsDouble());