Skip some conditional deopts for Div/Mul when all uses are truncating

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 5d1f46d065634bc7381850bddca5bf9c0362a740..bea7bc4a84cf876abc4afb680e625b70db6c3821 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1344,8 +1344,7 @@ void LCodeGen::DoModI(LModI* instr) {
 void LCodeGen::DoDivI(LDivI* instr) {
   if (!instr->is_flooring() && instr->hydrogen()->HasPowerOf2Divisor()) {
     Register dividend = ToRegister(instr->left());
-    int32_t divisor =
-        HConstant::cast(instr->hydrogen()->right())->Integer32Value();
+    int32_t divisor = instr->hydrogen()->right()->GetInteger32Constant();
     int32_t test_value = 0;
     int32_t power = 0;
 
@@ -1368,10 +1367,26 @@ void LCodeGen::DoDivI(LDivI* instr) {
     }
 
     if (test_value != 0) {
-      // Deoptimize if remainder is not 0.
-      __ test(dividend, Immediate(test_value));
-      DeoptimizeIf(not_zero, instr->environment());
-      __ sar(dividend, power);
+      if (instr->hydrogen()->CheckFlag(
+          HInstruction::kAllUsesTruncatingToInt32)) {
+        Label done, negative;
+        __ cmp(dividend, 0);
+        __ j(less, &negative, Label::kNear);
+        __ sar(dividend, power);
+        __ jmp(&done, Label::kNear);
+
+        __ bind(&negative);
+        __ neg(dividend);
+        __ sar(dividend, power);
+        if (divisor > 0) __ neg(dividend);
+        __ bind(&done);
+        return;  // Don't fall through to "__ neg" below.
+      } else {
+        // Deoptimize if remainder is not 0.
+        __ test(dividend, Immediate(test_value));
+        DeoptimizeIf(not_zero, instr->environment());
+        __ sar(dividend, power);
+      }
     }
 
     if (divisor < 0) __ neg(dividend);
@@ -1418,11 +1433,7 @@ void LCodeGen::DoDivI(LDivI* instr) {
   __ cdq();
   __ idiv(right_reg);
 
-  if (!instr->is_flooring()) {
-    // Deoptimize if remainder is not 0.
-    __ test(edx, Operand(edx));
-    DeoptimizeIf(not_zero, instr->environment());
-  } else {
+  if (instr->is_flooring()) {
     Label done;
     __ test(edx, edx);
     __ j(zero, &done, Label::kNear);
@@ -1430,6 +1441,11 @@ void LCodeGen::DoDivI(LDivI* instr) {
     __ sar(edx, 31);
     __ add(eax, edx);
     __ bind(&done);
+  } else if (!instr->hydrogen()->CheckFlag(
+      HInstruction::kAllUsesTruncatingToInt32)) {
+    // Deoptimize if remainder is not 0.
+    __ test(edx, Operand(edx));
+    DeoptimizeIf(not_zero, instr->environment());
   }
 }