X87: [TurboFan] Change the implementation of Float32's NaN comparision's return value in kX87Float3…

src/compiler/x87/code-generator-x87.cc

Index: src/compiler/x87/code-generator-x87.cc
diff --git a/src/compiler/x87/code-generator-x87.cc b/src/compiler/x87/code-generator-x87.cc
index 82eee57747f063eb2e8834beca898b6ca6c4ba4e..839f569685f7b08383ea906f7f77a2239b7b46c6 100644
--- a/src/compiler/x87/code-generator-x87.cc
+++ b/src/compiler/x87/code-generator-x87.cc
@@ -744,7 +744,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ fld(1);
       __ fld(1);
       __ FCmp();
-      __ j(parity_even, &check_nan_left, Label::kNear);  // At least one NaN.
+
+      // At least one NaN.
+      // Return the second operands if one of the two operands is NaN
+      __ j(parity_even, &return_right, Label::kNear);
       __ j(equal, &check_zero, Label::kNear);            // left == right.
       __ j(condition, &return_left, Label::kNear);
       __ jmp(&return_right, Label::kNear);
@@ -758,12 +761,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ fadd(1);
       __ jmp(&return_left, Label::kNear);
 
-      __ bind(&check_nan_left);
-      __ fld(0);
-      __ fld(0);
-      __ FCmp();                                      // NaN check.
-      __ j(parity_even, &return_left, Label::kNear);  // left == NaN.
-
       __ bind(&return_right);
       __ fxch();
 
@@ -781,7 +778,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ fld(1);
       __ fld(1);
       __ FCmp();
-      __ j(parity_even, &check_nan_left, Label::kNear);  // At least one NaN.
+      // At least one NaN.
+      // Return the second operands if one of the two operands is NaN
+      __ j(parity_even, &return_right, Label::kNear);
       __ j(equal, &check_zero, Label::kNear);            // left == right.
       __ j(condition, &return_left, Label::kNear);
       __ jmp(&return_right, Label::kNear);
@@ -808,11 +807,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ pop(eax);  // restore esp
       __ jmp(&return_left, Label::kNear);
 
-      __ bind(&check_nan_left);
-      __ fld(0);
-      __ fld(0);
-      __ FCmp();                                      // NaN check.
-      __ j(parity_even, &return_left, Label::kNear);  // left == NaN.
 
       __ bind(&return_right);
       __ fxch();