[turbofan] Improve code generation for unordered comparisons.

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index aba480de42319c58edd4e92c63004108ac5b2b6b..bf6b170e414b1eb568fb727e20ed69550ff512e8 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -1027,11 +1027,12 @@ static void VisitCompareZero(InstructionSelector* selector, Node* node,
 }
 
 
-// Shared routine for multiple float64 compare operations.
+// Shared routine for multiple float64 compare operations (inputs commuted).
 static void VisitFloat64Compare(InstructionSelector* selector, Node* node,
                                 FlagsContinuation* cont) {
-  VisitCompare(selector, kSSEFloat64Cmp, node->InputAt(0), node->InputAt(1),
-               cont, node->op()->HasProperty(Operator::kCommutative));
+  Node* const left = node->InputAt(0);
+  Node* const right = node->InputAt(1);
+  VisitCompare(selector, kSSEFloat64Cmp, right, left, cont, false);
 }
 
 
@@ -1102,10 +1103,10 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
         cont.OverwriteAndNegateIfEqual(kUnorderedEqual);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kFloat64LessThan:
-        cont.OverwriteAndNegateIfEqual(kUnorderedLessThan);
+        cont.OverwriteAndNegateIfEqual(kUnsignedGreaterThan);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kFloat64LessThanOrEqual:
-        cont.OverwriteAndNegateIfEqual(kUnorderedLessThanOrEqual);
+        cont.OverwriteAndNegateIfEqual(kUnsignedGreaterThanOrEqual);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kProjection:
         // Check if this is the overflow output projection of an
@@ -1291,13 +1292,13 @@ void InstructionSelector::VisitFloat64Equal(Node* node) {
 
 
 void InstructionSelector::VisitFloat64LessThan(Node* node) {
-  FlagsContinuation cont(kUnorderedLessThan, node);
+  FlagsContinuation cont(kUnsignedGreaterThan, node);
   VisitFloat64Compare(this, node, &cont);
 }
 
 
 void InstructionSelector::VisitFloat64LessThanOrEqual(Node* node) {
-  FlagsContinuation cont(kUnorderedLessThanOrEqual, node);
+  FlagsContinuation cont(kUnsignedGreaterThanOrEqual, node);
   VisitFloat64Compare(this, node, &cont);
 }