Emit VMLA for multiply-add on ARM

src/arm/lithium-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1285 matching lines @@
       left = UseRegisterAtStart(instr->LeastConstantOperand());
     }
     LMulI* mul = new(zone()) LMulI(left, right, temp);
     if (instr->CheckFlag(HValue::kCanOverflow) ||
         instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
       AssignEnvironment(mul);
     }
     return DefineAsRegister(mul);
 
   } else if (instr->representation().IsDouble()) {
+    if (instr->UseCount() == 1 && instr->uses().value()->IsAdd()) {
+      HAdd* add = HAdd::cast(instr->uses().value());
+      if (instr == add->left()) {
+        // This mul is the lhs of an add. The add and mul will be folded
+        // into a multiply-add.
+        return NULL;
+      }
+      if (instr == add->right() && !add->left()->IsMul()) {
+        // This mul is the rhs of an add, where the lhs is not another mul.
+        // The add and mul will be folded into a multiply-add.
+        return NULL;
+      }
+    }
+
     return DoArithmeticD(Token::MUL, instr);
-
   } else {
     return DoArithmeticT(Token::MUL, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoSub(HSub* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
     LOperand* left = UseRegisterAtStart(instr->left());
     LOperand* right = UseOrConstantAtStart(instr->right());
     LSubI* sub = new(zone()) LSubI(left, right);
     LInstruction* result = DefineAsRegister(sub);
     if (instr->CheckFlag(HValue::kCanOverflow)) {
       result = AssignEnvironment(result);
     }
     return result;
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::SUB, instr);
   } else {
     return DoArithmeticT(Token::SUB, instr);
   }
 }
 
+LInstruction* LChunkBuilder::DoMultiplyAdd(HMul* mul, HValue* addend) {
+  LOperand* multiplier_op = UseRegisterAtStart(mul->left());
+  LOperand* multiplicand_op = UseRegisterAtStart(mul->right());
+  LOperand* addend_op = UseRegisterAtStart(addend);
+  return DefineSameAsFirst(new(zone()) LMultiplyAddD(addend_op, multiplier_op,
+                                                     multiplicand_op));
+}
 
 LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
     LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
     LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
     LAddI* add = new(zone()) LAddI(left, right);
     LInstruction* result = DefineAsRegister(add);
     if (instr->CheckFlag(HValue::kCanOverflow)) {
       result = AssignEnvironment(result);
     }
     return result;
   } else if (instr->representation().IsDouble()) {
+    if (instr->left()->IsMul())
+      return DoMultiplyAdd(HMul::cast(instr->left()), instr->right());
+
+    if (instr->right()->IsMul()) {
+      ASSERT(!instr->left()->IsMul());
+      return DoMultiplyAdd(HMul::cast(instr->right()), instr->left());
+    }
+
     return DoArithmeticD(Token::ADD, instr);
   } else {
     ASSERT(instr->representation().IsTagged());
     return DoArithmeticT(Token::ADD, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoMathMinMax(HMathMinMax* instr) {
   LOperand* left = NULL;
@@ skipping 905 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal