Revert "ARM/ARM64: Extend support of instruction combining."
The test fails its checker parts.
This reverts commit debeb98aaa8950caf1a19df490f2ac9bf563075b.
Change-Id: I49929e15950c7814da6c411ecd2b640d12de80df
diff --git a/compiler/optimizing/instruction_simplifier_arm64.cc b/compiler/optimizing/instruction_simplifier_arm64.cc
index 83126a5..4bcfc54 100644
--- a/compiler/optimizing/instruction_simplifier_arm64.cc
+++ b/compiler/optimizing/instruction_simplifier_arm64.cc
@@ -17,7 +17,6 @@
#include "instruction_simplifier_arm64.h"
#include "common_arm64.h"
-#include "instruction_simplifier_shared.h"
#include "mirror/array-inl.h"
namespace art {
@@ -180,6 +179,67 @@
return true;
}
+bool InstructionSimplifierArm64Visitor::TrySimpleMultiplyAccumulatePatterns(
+ HMul* mul, HBinaryOperation* input_binop, HInstruction* input_other) {
+ DCHECK(Primitive::IsIntOrLongType(mul->GetType()));
+ DCHECK(input_binop->IsAdd() || input_binop->IsSub());
+ DCHECK_NE(input_binop, input_other);
+ if (!input_binop->HasOnlyOneNonEnvironmentUse()) {
+ return false;
+ }
+
+ // Try to interpret patterns like
+ // a * (b <+/-> 1)
+ // as
+ // (a * b) <+/-> a
+ HInstruction* input_a = input_other;
+ HInstruction* input_b = nullptr; // Set to a non-null value if we found a pattern to optimize.
+ HInstruction::InstructionKind op_kind;
+
+ if (input_binop->IsAdd()) {
+ if ((input_binop->GetConstantRight() != nullptr) && input_binop->GetConstantRight()->IsOne()) {
+ // Interpret
+ // a * (b + 1)
+ // as
+ // (a * b) + a
+ input_b = input_binop->GetLeastConstantLeft();
+ op_kind = HInstruction::kAdd;
+ }
+ } else {
+ DCHECK(input_binop->IsSub());
+ if (input_binop->GetRight()->IsConstant() &&
+ input_binop->GetRight()->AsConstant()->IsMinusOne()) {
+ // Interpret
+ // a * (b - (-1))
+ // as
+ // a + (a * b)
+ input_b = input_binop->GetLeft();
+ op_kind = HInstruction::kAdd;
+ } else if (input_binop->GetLeft()->IsConstant() &&
+ input_binop->GetLeft()->AsConstant()->IsOne()) {
+ // Interpret
+ // a * (1 - b)
+ // as
+ // a - (a * b)
+ input_b = input_binop->GetRight();
+ op_kind = HInstruction::kSub;
+ }
+ }
+
+ if (input_b == nullptr) {
+ // We did not find a pattern we can optimize.
+ return false;
+ }
+
+ HArm64MultiplyAccumulate* mulacc = new(GetGraph()->GetArena()) HArm64MultiplyAccumulate(
+ mul->GetType(), op_kind, input_a, input_a, input_b, mul->GetDexPc());
+
+ mul->GetBlock()->ReplaceAndRemoveInstructionWith(mul, mulacc);
+ input_binop->GetBlock()->RemoveInstruction(input_binop);
+
+ return false;
+}
+
void InstructionSimplifierArm64Visitor::VisitArrayGet(HArrayGet* instruction) {
TryExtractArrayAccessAddress(instruction,
instruction->GetArray(),
@@ -195,8 +255,75 @@
}
void InstructionSimplifierArm64Visitor::VisitMul(HMul* instruction) {
- if (TryCombineMultiplyAccumulate(instruction, kArm64)) {
- RecordSimplification();
+ Primitive::Type type = instruction->GetType();
+ if (!Primitive::IsIntOrLongType(type)) {
+ return;
+ }
+
+ HInstruction* use = instruction->HasNonEnvironmentUses()
+ ? instruction->GetUses().GetFirst()->GetUser()
+ : nullptr;
+
+ if (instruction->HasOnlyOneNonEnvironmentUse() && (use->IsAdd() || use->IsSub())) {
+ // Replace code looking like
+ // MUL tmp, x, y
+ // SUB dst, acc, tmp
+ // with
+ // MULSUB dst, acc, x, y
+ // Note that we do not want to (unconditionally) perform the merge when the
+ // multiplication has multiple uses and it can be merged in all of them.
+ // Multiple uses could happen on the same control-flow path, and we would
+ // then increase the amount of work. In the future we could try to evaluate
+ // whether all uses are on different control-flow paths (using dominance and
+ // reverse-dominance information) and only perform the merge when they are.
+ HInstruction* accumulator = nullptr;
+ HBinaryOperation* binop = use->AsBinaryOperation();
+ HInstruction* binop_left = binop->GetLeft();
+ HInstruction* binop_right = binop->GetRight();
+ // Be careful after GVN. This should not happen since the `HMul` has only
+ // one use.
+ DCHECK_NE(binop_left, binop_right);
+ if (binop_right == instruction) {
+ accumulator = binop_left;
+ } else if (use->IsAdd()) {
+ DCHECK_EQ(binop_left, instruction);
+ accumulator = binop_right;
+ }
+
+ if (accumulator != nullptr) {
+ HArm64MultiplyAccumulate* mulacc =
+ new (GetGraph()->GetArena()) HArm64MultiplyAccumulate(type,
+ binop->GetKind(),
+ accumulator,
+ instruction->GetLeft(),
+ instruction->GetRight());
+
+ binop->GetBlock()->ReplaceAndRemoveInstructionWith(binop, mulacc);
+ DCHECK(!instruction->HasUses());
+ instruction->GetBlock()->RemoveInstruction(instruction);
+ RecordSimplification();
+ return;
+ }
+ }
+
+ // Use multiply accumulate instruction for a few simple patterns.
+ // We prefer not applying the following transformations if the left and
+ // right inputs perform the same operation.
+ // We rely on GVN having squashed the inputs if appropriate. However the
+ // results are still correct even if that did not happen.
+ if (instruction->GetLeft() == instruction->GetRight()) {
+ return;
+ }
+
+ HInstruction* left = instruction->GetLeft();
+ HInstruction* right = instruction->GetRight();
+ if ((right->IsAdd() || right->IsSub()) &&
+ TrySimpleMultiplyAccumulatePatterns(instruction, right->AsBinaryOperation(), left)) {
+ return;
+ }
+ if ((left->IsAdd() || left->IsSub()) &&
+ TrySimpleMultiplyAccumulatePatterns(instruction, left->AsBinaryOperation(), right)) {
+ return;
}
}