Emit VMLS for multiply-subtract on ARM.

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index a93e8980454ff081cdb3b48db5891185d8ffc01a..791a03274d7a45cfbc99dbb948d503b7259b15d2 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -139,6 +139,7 @@ class LCodeGen;
   V(ModI)                                       \
   V(MulI)                                       \
   V(MultiplyAddD)                               \
+  V(MultiplySubD)                               \
   V(NumberTagD)                                 \
   V(NumberTagI)                                 \
   V(NumberTagU)                                 \
@@ -660,6 +661,24 @@ class LMultiplyAddD: public LTemplateInstruction<1, 3, 0> {
 };
 
 
+// Instruction for computing minuend - multiplier * multiplicand.
+class LMultiplySubD: public LTemplateInstruction<1, 3, 0> {
+ public:
+  LMultiplySubD(LOperand* minuend, LOperand* multiplier,
+                LOperand* multiplicand) {
+    inputs_[0] = minuend;
+    inputs_[1] = multiplier;
+    inputs_[2] = multiplicand;
+  }
+
+  LOperand* minuend() { return inputs_[0]; }
+  LOperand* multiplier() { return inputs_[1]; }
+  LOperand* multiplicand() { return inputs_[2]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(MultiplySubD, "multiply-sub-d")
+};
+
+
 class LCmpIDAndBranch: public LControlInstruction<2, 0> {
  public:
   LCmpIDAndBranch(LOperand* left, LOperand* right) {
@@ -2540,6 +2559,7 @@ class LChunkBuilder BASE_EMBEDDED {
 #undef DECLARE_DO
 
   LInstruction* DoMultiplyAdd(HMul* mul, HValue* addend);
+  LInstruction* DoMultiplySub(HValue* minuend, HMul* mul);
   LInstruction* DoRSub(HSub* instr);
 
   static bool HasMagicNumberForDivisor(int32_t divisor);