Refactor Math.min/max to be a single HInstruction.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 24b991e831a4102c9dffd412c4390658d6a3c26a..83299817d44f2bb443c89ce5ea8bd5171840a066 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1330,6 +1330,26 @@ LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoMathMinMax(HMathMinMax* instr) {
+  LOperand* left = NULL;
+  LOperand* right = NULL;
+  if (instr->representation().IsInteger32()) {
+    ASSERT(instr->left()->representation().IsInteger32());
+    ASSERT(instr->right()->representation().IsInteger32());
+    left = UseRegisterAtStart(instr->LeastConstantOperand());
+    right = UseOrConstantAtStart(instr->MostConstantOperand());
+  } else {
+    ASSERT(instr->representation().IsDouble());
+    ASSERT(instr->left()->representation().IsDouble());
+    ASSERT(instr->right()->representation().IsDouble());
+    left = UseRegisterAtStart(instr->left());
+    right = UseRegisterAtStart(instr->right());
+  }
+  LMathMinMax* minmax = new(zone()) LMathMinMax(left, right);
+  return DefineSameAsFirst(minmax);
+}
+
+
 LInstruction* LChunkBuilder::DoPower(HPower* instr) {
   ASSERT(instr->representation().IsDouble());
   // We call a C function for double power. It can't trigger a GC.