[llvm] r228432 - [InstSimplify] Add SimplifyFPBinOp function.
Michael Zolotukhin
mzolotukhin at apple.com
Mon Feb 9 14:22:13 PST 2015
Hi Chandler, Chad,
Could you please take a look at the attached testcase?
Is it ok to commit it?
Thanks,
Michael
> On Feb 6, 2015, at 12:23 PM, Michael Zolotukhin <mzolotukhin at apple.com> wrote:
>
>> On Feb 6, 2015, at 12:10 PM, Chad Rosier <mcrosier at codeaurora.org <mailto:mcrosier at codeaurora.org>> wrote:
>>
>> testcase?
> I’ll follow up shortly with that.
>
> Thanks,
> Michael
>
>>
>>> Author: mzolotukhin
>>> Date: Fri Feb 6 14:02:51 2015
>>> New Revision: 228432
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=228432&view=rev
>>> Log:
>>> [InstSimplify] Add SimplifyFPBinOp function.
>>>
>>> It is a variation of SimplifyBinOp, but it takes into account
>>> FastMathFlags.
>>>
>>> It is needed in inliner and loop-unroller to accurately predict the
>>> transformation's outcome (previously we dropped the flags and were too
>>> conservative in some cases).
>>>
>>> Example:
>>> float foo(float *a, float b) {
>>> float r;
>>> if (a[1] * b)
>>> r = /* a lot of expensive computations */;
>>> else
>>> r = 1;
>>> return r;
>>> }
>>> float boo(float *a) {
>>> return foo(a, 0.0);
>>> }
>>>
>>> Without this patch, we don't inline 'foo' into 'boo'.
>>>
>>> Modified:
>>> llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
>>> llvm/trunk/lib/Analysis/IPA/InlineCost.cpp
>>> llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>>> llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
>>>
>>> Modified: llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/InstructionSimplify.h?rev=228432&r1=228431&r2=228432&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/Analysis/InstructionSimplify.h (original)
>>> +++ llvm/trunk/include/llvm/Analysis/InstructionSimplify.h Fri Feb 6
>>> 14:02:51 2015
>>> @@ -277,6 +277,17 @@ namespace llvm {
>>> const DominatorTree *DT = nullptr,
>>> AssumptionCache *AC = nullptr,
>>> const Instruction *CxtI = nullptr);
>>> + /// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we
>>> can
>>> + /// fold the result. If not, this returns null.
>>> + /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding
>>> the
>>> + /// result. In case we don't need FastMathFlags, simply fall to
>>> SimplifyBinOp.
>>> + Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
>>> + const FastMathFlags &FMF,
>>> + const DataLayout *TD = nullptr,
>>> + const TargetLibraryInfo *TLI = nullptr,
>>> + const DominatorTree *DT = nullptr,
>>> + AssumptionCache *AC = nullptr,
>>> + const Instruction *CxtI = nullptr);
>>>
>>> /// \brief Given a function and iterators over arguments, see if we can
>>> fold
>>> /// the result.
>>>
>>> Modified: llvm/trunk/lib/Analysis/IPA/InlineCost.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/IPA/InlineCost.cpp?rev=228432&r1=228431&r2=228432&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Analysis/IPA/InlineCost.cpp (original)
>>> +++ llvm/trunk/lib/Analysis/IPA/InlineCost.cpp Fri Feb 6 14:02:51 2015
>>> @@ -601,7 +601,13 @@ bool CallAnalyzer::visitBinaryOperator(B
>>> if (!isa<Constant>(RHS))
>>> if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
>>> RHS = SimpleRHS;
>>> - Value *SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);
>>> + Value *SimpleV = nullptr;
>>> + if (auto FI = dyn_cast<FPMathOperator>(&I))
>>> + SimpleV =
>>> + SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(),
>>> DL);
>>> + else
>>> + SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);
>>> +
>>> if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) {
>>> SimplifiedValues[&I] = C;
>>> return true;
>>>
>>> Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=228432&r1=228431&r2=228432&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
>>> +++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Feb 6 14:02:51
>>> 2015
>>> @@ -61,6 +61,8 @@ struct Query {
>>> static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
>>> static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
>>> unsigned);
>>> +static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const
>>> FastMathFlags &,
>>> + const Query &, unsigned);
>>> static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
>>> unsigned);
>>> static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
>>> @@ -3465,6 +3467,25 @@ static Value *SimplifyBinOp(unsigned Opc
>>> }
>>> }
>>>
>>> +/// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can
>>> +/// fold the result. If not, this returns null.
>>> +/// In contrast to SimplifyBinOp, try to use FastMathFlag when folding
>>> the
>>> +/// result. In case we don't need FastMathFlags, simply fall to
>>> SimplifyBinOp.
>>> +static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
>>> + const FastMathFlags &FMF, const Query &Q,
>>> + unsigned MaxRecurse) {
>>> + switch (Opcode) {
>>> + case Instruction::FAdd:
>>> + return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
>>> + case Instruction::FSub:
>>> + return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
>>> + case Instruction::FMul:
>>> + return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
>>> + default:
>>> + return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
>>> + }
>>> +}
>>> +
>>> Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
>>> const DataLayout *DL, const TargetLibraryInfo
>>> *TLI,
>>> const DominatorTree *DT, AssumptionCache *AC,
>>> @@ -3473,6 +3494,15 @@ Value *llvm::SimplifyBinOp(unsigned Opco
>>> RecursionLimit);
>>> }
>>>
>>> +Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
>>> + const FastMathFlags &FMF, const DataLayout
>>> *DL,
>>> + const TargetLibraryInfo *TLI,
>>> + const DominatorTree *DT, AssumptionCache
>>> *AC,
>>> + const Instruction *CxtI) {
>>> + return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Query(DL, TLI, DT, AC,
>>> CxtI),
>>> + RecursionLimit);
>>> +}
>>> +
>>> /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
>>> /// fold the result.
>>> static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
>>>
>>> Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp?rev=228432&r1=228431&r2=228432&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp (original)
>>> +++ llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp Fri Feb 6
>>> 14:02:51 2015
>>> @@ -311,7 +311,12 @@ class UnrollAnalyzer : public InstVisito
>>> if (!isa<Constant>(RHS))
>>> if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
>>> RHS = SimpleRHS;
>>> - Value *SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS);
>>> + Value *SimpleV = nullptr;
>>> + if (auto FI = dyn_cast<FPMathOperator>(&I))
>>> + SimpleV =
>>> + SimplifyFPBinOp(I.getOpcode(), LHS, RHS,
>>> FI->getFastMathFlags());
>>> + else
>>> + SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS);
>>>
>>> if (SimpleV && CountedInsns.insert(&I).second)
>>> NumberOfOptimizedInstructions += TTI.getUserCost(&I);
>>>
>>>
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>>> llvm-commits at cs.uiuc.edu
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>>>
>>
>>
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