Emit VMLA for multiply-add on ARM

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 51ae7f5a44c29fc4b69f66651b95fcfef7a6f2fa..658e265b9fbb0749a4c5c1dd3c531cb633fc6fc8 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -8282,6 +8282,24 @@ bool CanBeZero(HValue *right) {
 }
 
 
+bool HGraphBuilder::MatchMultiplyAdd(HValue* left, HValue* right, HValue** a, HValue** b, HValue** c) {
+  if (right->IsMul()) {
+    HValue *tmp = left;
+    left = right;
+    right = tmp;
+  }
+  if (!left->IsMul())
+    return false;
+
+  HMul* mul = HMul::cast(left);
+  *a = mul->left();
+  *b = mul->right();
+  *c = right;
+  //printf("matched multiply-add\n");
+  return true;
+}
+
+
 HInstruction* HGraphBuilder::BuildBinaryOperation(BinaryOperation* expr,
                                                   HValue* left,
                                                   HValue* right) {
@@ -8294,17 +8312,27 @@ HInstruction* HGraphBuilder::BuildBinaryOperation(BinaryOperation* expr,
   }
   HInstruction* instr = NULL;
   switch (expr->op()) {
-    case Token::ADD:
+    case Token::ADD: {
+#ifdef V8_TARGET_ARCH_ARM
+      HValue* a, *b, *c;
+#endif
       if (info.IsString()) {
         AddInstruction(new(zone()) HCheckNonSmi(left));
         AddInstruction(HCheckInstanceType::NewIsString(left, zone()));
         AddInstruction(new(zone()) HCheckNonSmi(right));
         AddInstruction(HCheckInstanceType::NewIsString(right, zone()));
         instr = new(zone()) HStringAdd(context, left, right);
+#ifdef V8_TARGET_ARCH_ARM
+      } else if (info.IsDouble() && MatchMultiplyAdd(left, right, &a, &b, &c)) {
+        // FIXME: Probably need to check types here?

[ulan_google, 2012/11/07 09:54:03]

Setting input representation should be sufficient. Hydrogen will introduce
special change instructions for inputs.

+        // FIXME: I'm not sure I'm hooking this up correctly :/
+        instr = new(zone()) HMultiplyAdd(context, a, b, c);
+#endif
       } else {
         instr = HAdd::NewHAdd(zone(), context, left, right);
       }
       break;
+    }
     case Token::SUB:
       instr = HSub::NewHSub(zone(), context, left, right);
       break;