From 3b55ebb22156e1f3496cd1ee4a05e03b4780e579 Mon Sep 17 00:00:00 2001 From: Roland Levillain Date: Fri, 8 May 2015 13:13:19 +0100 Subject: Simplify floating-point comparisons with NaN in Optimizing. This change was suggested by Ian. Also, simplify some art::HFloatConstant and art::HDoubleConstant methods. Change-Id: I7908df23581a7f61c8ec79c290fe5f70798ac3be --- compiler/optimizing/constant_folding.cc | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'compiler/optimizing/constant_folding.cc') diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc index b7a92b5ae5..5a1d9b488f 100644 --- a/compiler/optimizing/constant_folding.cc +++ b/compiler/optimizing/constant_folding.cc @@ -28,6 +28,7 @@ class InstructionWithAbsorbingInputSimplifier : public HGraphVisitor { void VisitShift(HBinaryOperation* shift); void VisitAnd(HAnd* instruction) OVERRIDE; + void VisitCompare(HCompare* instruction) OVERRIDE; void VisitMul(HMul* instruction) OVERRIDE; void VisitOr(HOr* instruction) OVERRIDE; void VisitRem(HRem* instruction) OVERRIDE; @@ -108,6 +109,26 @@ void InstructionWithAbsorbingInputSimplifier::VisitAnd(HAnd* instruction) { } } +void InstructionWithAbsorbingInputSimplifier::VisitCompare(HCompare* instruction) { + HConstant* input_cst = instruction->GetConstantRight(); + if (input_cst != nullptr) { + HInstruction* input_value = instruction->GetLeastConstantLeft(); + if (Primitive::IsFloatingPointType(input_value->GetType()) && + ((input_cst->IsFloatConstant() && input_cst->AsFloatConstant()->IsNaN()) || + (input_cst->IsDoubleConstant() && input_cst->AsDoubleConstant()->IsNaN()))) { + // Replace code looking like + // CMP{G,L} dst, src, NaN + // with + // CONSTANT +1 (gt bias) + // or + // CONSTANT -1 (lt bias) + instruction->ReplaceWith(GetGraph()->GetConstant(Primitive::kPrimInt, + (instruction->IsGtBias() ? 1 : -1))); + instruction->GetBlock()->RemoveInstruction(instruction); + } + } +} + void InstructionWithAbsorbingInputSimplifier::VisitMul(HMul* instruction) { HConstant* input_cst = instruction->GetConstantRight(); Primitive::Type type = instruction->GetType(); -- cgit v1.2.3-59-g8ed1b