diff options
Diffstat (limited to 'compiler/optimizing/instruction_simplifier_arm64.cc')
-rw-r--r-- | compiler/optimizing/instruction_simplifier_arm64.cc | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/compiler/optimizing/instruction_simplifier_arm64.cc b/compiler/optimizing/instruction_simplifier_arm64.cc index 83126a5c4d..c2bbdccc29 100644 --- a/compiler/optimizing/instruction_simplifier_arm64.cc +++ b/compiler/optimizing/instruction_simplifier_arm64.cc @@ -180,6 +180,53 @@ bool InstructionSimplifierArm64Visitor::TryMergeIntoUsersShifterOperand(HInstruc return true; } +bool InstructionSimplifierArm64Visitor::TryMergeNegatedInput(HBinaryOperation* op) { + DCHECK(op->IsAnd() || op->IsOr() || op->IsXor()) << op->DebugName(); + HInstruction* left = op->GetLeft(); + HInstruction* right = op->GetRight(); + + // Only consider the case where there is exactly one Not, with 2 Not's De + // Morgan's laws should be applied instead. + if (left->IsNot() ^ right->IsNot()) { + HInstruction* hnot = (left->IsNot() ? left : right); + HInstruction* hother = (left->IsNot() ? right : left); + + // Only do the simplification if the Not has only one use and can thus be + // safely removed. Even though ARM64 negated bitwise operations do not have + // an immediate variant (only register), we still do the simplification when + // `hother` is a constant, because it removes an instruction if the constant + // cannot be encoded as an immediate: + // mov r0, #large_constant + // neg r2, r1 + // and r0, r0, r2 + // becomes: + // mov r0, #large_constant + // bic r0, r0, r1 + if (hnot->HasOnlyOneNonEnvironmentUse()) { + // Replace code looking like + // NOT tmp, mask + // AND dst, src, tmp (respectively ORR, EOR) + // with + // BIC dst, src, mask (respectively ORN, EON) + HInstruction* src = hnot->AsNot()->GetInput(); + + HArm64BitwiseNegatedRight* neg_op = new (GetGraph()->GetArena()) + HArm64BitwiseNegatedRight(op->GetType(), op->GetKind(), hother, src, op->GetDexPc()); + + op->GetBlock()->ReplaceAndRemoveInstructionWith(op, neg_op); + hnot->GetBlock()->RemoveInstruction(hnot); + RecordSimplification(); + return true; + } + } + + return false; +} + +void InstructionSimplifierArm64Visitor::VisitAnd(HAnd* instruction) { + TryMergeNegatedInput(instruction); +} + void InstructionSimplifierArm64Visitor::VisitArrayGet(HArrayGet* instruction) { TryExtractArrayAccessAddress(instruction, instruction->GetArray(), @@ -200,6 +247,10 @@ void InstructionSimplifierArm64Visitor::VisitMul(HMul* instruction) { } } +void InstructionSimplifierArm64Visitor::VisitOr(HOr* instruction) { + TryMergeNegatedInput(instruction); +} + void InstructionSimplifierArm64Visitor::VisitShl(HShl* instruction) { if (instruction->InputAt(1)->IsConstant()) { TryMergeIntoUsersShifterOperand(instruction); @@ -232,5 +283,9 @@ void InstructionSimplifierArm64Visitor::VisitUShr(HUShr* instruction) { } } +void InstructionSimplifierArm64Visitor::VisitXor(HXor* instruction) { + TryMergeNegatedInput(instruction); +} + } // namespace arm64 } // namespace art |