Revert "Revert "ARM/ARM64: Extend support of instruction combining.""
This reverts commit 6b5afdd144d2bb3bf994240797834b5666b2cf98.
Change-Id: Ic27a10f02e21109503edd64e6d73d1bb0c6a8ac6
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 814f8b4..beb75f0 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -1959,21 +1959,27 @@
Operand(InputOperandAt(instruction, 1)));
}
-void LocationsBuilderARM64::VisitArm64MultiplyAccumulate(HArm64MultiplyAccumulate* instr) {
+void LocationsBuilderARM64::VisitMultiplyAccumulate(HMultiplyAccumulate* instr) {
LocationSummary* locations =
new (GetGraph()->GetArena()) LocationSummary(instr, LocationSummary::kNoCall);
- locations->SetInAt(HArm64MultiplyAccumulate::kInputAccumulatorIndex,
- Location::RequiresRegister());
- locations->SetInAt(HArm64MultiplyAccumulate::kInputMulLeftIndex, Location::RequiresRegister());
- locations->SetInAt(HArm64MultiplyAccumulate::kInputMulRightIndex, Location::RequiresRegister());
+ HInstruction* accumulator = instr->InputAt(HMultiplyAccumulate::kInputAccumulatorIndex);
+ if (instr->GetOpKind() == HInstruction::kSub &&
+ accumulator->IsConstant() &&
+ accumulator->AsConstant()->IsZero()) {
+ // Don't allocate register for Mneg instruction.
+ } else {
+ locations->SetInAt(HMultiplyAccumulate::kInputAccumulatorIndex,
+ Location::RequiresRegister());
+ }
+ locations->SetInAt(HMultiplyAccumulate::kInputMulLeftIndex, Location::RequiresRegister());
+ locations->SetInAt(HMultiplyAccumulate::kInputMulRightIndex, Location::RequiresRegister());
locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
}
-void InstructionCodeGeneratorARM64::VisitArm64MultiplyAccumulate(HArm64MultiplyAccumulate* instr) {
+void InstructionCodeGeneratorARM64::VisitMultiplyAccumulate(HMultiplyAccumulate* instr) {
Register res = OutputRegister(instr);
- Register accumulator = InputRegisterAt(instr, HArm64MultiplyAccumulate::kInputAccumulatorIndex);
- Register mul_left = InputRegisterAt(instr, HArm64MultiplyAccumulate::kInputMulLeftIndex);
- Register mul_right = InputRegisterAt(instr, HArm64MultiplyAccumulate::kInputMulRightIndex);
+ Register mul_left = InputRegisterAt(instr, HMultiplyAccumulate::kInputMulLeftIndex);
+ Register mul_right = InputRegisterAt(instr, HMultiplyAccumulate::kInputMulRightIndex);
// Avoid emitting code that could trigger Cortex A53's erratum 835769.
// This fixup should be carried out for all multiply-accumulate instructions:
@@ -1993,10 +1999,17 @@
}
if (instr->GetOpKind() == HInstruction::kAdd) {
+ Register accumulator = InputRegisterAt(instr, HMultiplyAccumulate::kInputAccumulatorIndex);
__ Madd(res, mul_left, mul_right, accumulator);
} else {
DCHECK(instr->GetOpKind() == HInstruction::kSub);
- __ Msub(res, mul_left, mul_right, accumulator);
+ HInstruction* accum_instr = instr->InputAt(HMultiplyAccumulate::kInputAccumulatorIndex);
+ if (accum_instr->IsConstant() && accum_instr->AsConstant()->IsZero()) {
+ __ Mneg(res, mul_left, mul_right);
+ } else {
+ Register accumulator = InputRegisterAt(instr, HMultiplyAccumulate::kInputAccumulatorIndex);
+ __ Msub(res, mul_left, mul_right, accumulator);
+ }
}
}