[llvm] r340947 - [InstCombine] Expand the simplification of pow() into exp2()
Evandro Menezes via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 30 11:01:24 PDT 2018
Hey, Reid.
I don't have access to a Windows machine. Would it be possible for you
to try the new patch at https://reviews.llvm.org/D49273?
Thank you,
--
Evandro Menezes
On 08/29/2018 06:19 PM, Reid Kleckner wrote:
> It's a name LLVM makes up when mangling unnamed private globals
> like @0 = global i32. I'm not yet sure how your change causes these
> problems, but I've gone ahead and reverted your change in r340991 and
> am starting a reduction now. I have to run soon so I won't be able to
> share it until tomorrow, most likely.
>
> On Wed, Aug 29, 2018 at 4:05 PM Evandro Menezes <e.menezes at samsung.com
> <mailto:e.menezes at samsung.com>> wrote:
>
> Reid,
>
> Can you please provide an indication of what this symbol is about,
> as I'm not familiar with the VS linker?
>
> Thank you,
>
> --
> Evandro Menezes
>
> On 08/29/2018 05:50 PM, Reid Kleckner wrote:
>> My bisection shows that this broke the clang stage 2 build:
>> http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/13525
>>
>> We end up with references to __unnamed_1 globals that are
>> unresolved. I'll revert and get a reproducer.
>>
>> On Wed, Aug 29, 2018 at 11:00 AM Evandro Menezes via llvm-commits
>> <llvm-commits at lists.llvm.org
>> <mailto:llvm-commits at lists.llvm.org>> wrote:
>>
>> Author: evandro
>> Date: Wed Aug 29 10:59:34 2018
>> New Revision: 340947
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=340947&view=rev
>> Log:
>> [InstCombine] Expand the simplification of pow() into exp2()
>>
>> Generalize the simplification of `pow(2.0, y)` to `pow(2.0 **
>> n, y)` for all
>> scalar and vector types.
>>
>> This improvement helps some benchmarks in SPEC CPU2000 and
>> CPU2006, such as
>> 252.eon, 447.dealII, 453.povray. Otherwise, no significant
>> regressions on
>> x86-64 or A64.
>>
>> Differential revision: https://reviews.llvm.org/D49273
>>
>> Modified:
>> llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
>> llvm/trunk/test/Transforms/InstCombine/pow-1.ll
>>
>> Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=340947&r1=340946&r2=340947&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
>> (original)
>> +++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Wed
>> Aug 29 10:59:34 2018
>> @@ -13,6 +13,7 @@
>> //===----------------------------------------------------------------------===//
>>
>> #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
>> +#include "llvm/ADT/APSInt.h"
>> #include "llvm/ADT/SmallString.h"
>> #include "llvm/ADT/StringMap.h"
>> #include "llvm/ADT/Triple.h"
>> @@ -1183,12 +1184,13 @@ static Value *getPow(Value *InnerChain[3
>> }
>>
>> /// Use exp{,2}(x * y) for pow(exp{,2}(x), y);
>> -/// exp2(x) for pow(2.0, x); exp10(x) for pow(10.0, x).
>> +/// exp2(n * x) for pow(2.0 ** n, x); exp10(x) for pow(10.0, x).
>> Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow,
>> IRBuilder<> &B) {
>> Value *Base = Pow->getArgOperand(0), *Expo =
>> Pow->getArgOperand(1);
>> AttributeList Attrs =
>> Pow->getCalledFunction()->getAttributes();
>> Module *Mod = Pow->getModule();
>> Type *Ty = Pow->getType();
>> + bool Ignored;
>>
>> // Evaluate special cases related to a nested function as
>> the base.
>>
>> @@ -1232,10 +1234,28 @@ Value *LibCallSimplifier::replacePowWith
>>
>> // Evaluate special cases related to a constant base.
>>
>> - // pow(2.0, x) -> exp2(x)
>> - if (match(Base, m_SpecificFP(2.0))) {
>> - Value *Exp2 = Intrinsic::getDeclaration(Mod,
>> Intrinsic::exp2, Ty);
>> - return B.CreateCall(Exp2, Expo, "exp2");
>> + const APFloat *BaseF;
>> + if (!match(Pow->getArgOperand(0), m_APFloat(BaseF)))
>> + return nullptr;
>> +
>> + // pow(2.0 ** n, x) -> exp2(n * x)
>> + APFloat BaseR = APFloat(1.0);
>> + BaseR.convert(BaseF->getSemantics(),
>> APFloat::rmTowardZero, &Ignored);
>> + BaseR = BaseR / *BaseF;
>> + bool IsInteger = BaseF->isInteger(),
>> + IsReciprocal = BaseR.isInteger();
>> + const APFloat *NF = IsReciprocal ? &BaseR : BaseF;
>> + APSInt NI(64, false);
>> + if ((IsInteger || IsReciprocal) &&
>> + !NF->convertToInteger(NI, APFloat::rmTowardZero,
>> &Ignored) &&
>> + NI > 1 && NI.isPowerOf2()) {
>> + double N = NI.logBase2() * (IsReciprocal ? -1.0 : 1.0);
>> + Value *FMul = B.CreateFMul(Expo, ConstantFP::get(Ty, N),
>> "mul");
>> + if (Pow->doesNotAccessMemory())
>> + return B.CreateCall(Intrinsic::getDeclaration(Mod,
>> Intrinsic::exp2, Ty),
>> + FMul, "exp2");
>> + else
>> + return emitUnaryFloatFnCall(FMul,
>> TLI->getName(LibFunc_exp2), B, Attrs);
>> }
>>
>> // pow(10.0, x) -> exp10(x)
>>
>> Modified: llvm/trunk/test/Transforms/InstCombine/pow-1.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/pow-1.ll?rev=340947&r1=340946&r2=340947&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/InstCombine/pow-1.ll (original)
>> +++ llvm/trunk/test/Transforms/InstCombine/pow-1.ll Wed Aug
>> 29 10:59:34 2018
>> @@ -16,6 +16,7 @@
>>
>> declare float @powf(float, float) nounwind readonly
>> declare double @pow(double, double) nounwind readonly
>> +declare double @llvm.pow.f64(double, double)
>> declare <2 x float> @llvm.pow.v2f32(<2 x float>, <2 x
>> float>) nounwind readonly
>> declare <2 x double> @llvm.pow.v2f64(<2 x double>, <2 x
>> double>) nounwind readonly
>>
>> @@ -57,18 +58,18 @@ define <2 x double> @test_simplify2v(<2
>>
>> define float @test_simplify3(float %x) {
>> ; ANY-LABEL: @test_simplify3(
>> -; ANY-NEXT: [[EXP2:%.*]] = call float
>> @llvm.exp2.f32(float [[X:%.*]])
>> -; ANY-NEXT: ret float [[EXP2]]
>> +; ANY-NEXT: [[EXP2F:%.*]] = call float @exp2f(float
>> [[X:%.*]]) [[NUW_RO:#[0-9]+]]
>> +; ANY-NEXT: ret float [[EXP2F]]
>> ;
>> %retval = call float @powf(float 2.0, float %x)
>> ret float %retval
>> }
>>
>> -; TODO: Should result in exp2(-2.0 * x).
>> define double @test_simplify3n(double %x) {
>> ; ANY-LABEL: @test_simplify3n(
>> -; ANY-NEXT: [[RETVAL:%.*]] = call double @pow(double
>> 2.500000e-01, double [[X:%.*]])
>> -; ANY-NEXT: ret double [[RETVAL]]
>> +; ANY-NEXT: [[MUL:%.*]] = fmul double [[X:%.*]],
>> -2.000000e+00
>> +; ANY-NEXT: [[EXP2:%.*]] = call double @exp2(double
>> [[MUL]]) [[NUW_RO]]
>> +; ANY-NEXT: ret double [[EXP2]]
>> ;
>> %retval = call double @pow(double 0.25, double %x)
>> ret double %retval
>> @@ -83,11 +84,11 @@ define <2 x float> @test_simplify3v(<2 x
>> ret <2 x float> %retval
>> }
>>
>> -; TODO: Should result in exp2(2.0 * x).
>> define <2 x double> @test_simplify3vn(<2 x double> %x) {
>> ; ANY-LABEL: @test_simplify3vn(
>> -; ANY-NEXT: [[RETVAL:%.*]] = call <2 x double>
>> @llvm.pow.v2f64(<2 x double> <double 4.000000e+00, double
>> 4.000000e+00>, <2 x double> [[X:%.*]])
>> -; ANY-NEXT: ret <2 x double> [[RETVAL]]
>> +; ANY-NEXT: [[MUL:%.*]] = fmul <2 x double> [[X:%.*]],
>> <double 2.000000e+00, double 2.000000e+00>
>> +; ANY-NEXT: [[EXP2:%.*]] = call <2 x double>
>> @llvm.exp2.v2f64(<2 x double> [[MUL]])
>> +; ANY-NEXT: ret <2 x double> [[EXP2]]
>> ;
>> %retval = call <2 x double> @llvm.pow.v2f64(<2 x double>
>> <double 4.0, double 4.0>, <2 x double> %x)
>> ret <2 x double> %retval
>> @@ -95,18 +96,18 @@ define <2 x double> @test_simplify3vn(<2
>>
>> define double @test_simplify4(double %x) {
>> ; ANY-LABEL: @test_simplify4(
>> -; ANY-NEXT: [[EXP2:%.*]] = call double
>> @llvm.exp2.f64(double [[X:%.*]])
>> +; ANY-NEXT: [[EXP2:%.*]] = call double @exp2(double
>> [[X:%.*]]) [[NUW_RO]]
>> ; ANY-NEXT: ret double [[EXP2]]
>> ;
>> %retval = call double @pow(double 2.0, double %x)
>> ret double %retval
>> }
>>
>> -; TODO: Should result in exp2f(3.0 * x).
>> define float @test_simplify4n(float %x) {
>> ; ANY-LABEL: @test_simplify4n(
>> -; ANY-NEXT: [[RETVAL:%.*]] = call float @powf(float
>> 8.000000e+00, float [[X:%.*]])
>> -; ANY-NEXT: ret float [[RETVAL]]
>> +; ANY-NEXT: [[MUL:%.*]] = fmul float [[X:%.*]], 3.000000e+00
>> +; ANY-NEXT: [[EXP2F:%.*]] = call float @exp2f(float
>> [[MUL]]) [[NUW_RO]]
>> +; ANY-NEXT: ret float [[EXP2F]]
>> ;
>> %retval = call float @powf(float 8.0, float %x)
>> ret float %retval
>> @@ -121,11 +122,11 @@ define <2 x double> @test_simplify4v(<2
>> ret <2 x double> %retval
>> }
>>
>> -; TODO: Should result in exp2f(-x).
>> define <2 x float> @test_simplify4vn(<2 x float> %x) {
>> ; ANY-LABEL: @test_simplify4vn(
>> -; ANY-NEXT: [[RETVAL:%.*]] = call <2 x float>
>> @llvm.pow.v2f32(<2 x float> <float 5.000000e-01, float
>> 5.000000e-01>, <2 x float> [[X:%.*]])
>> -; ANY-NEXT: ret <2 x float> [[RETVAL]]
>> +; ANY-NEXT: [[MUL:%.*]] = fsub <2 x float> <float
>> -0.000000e+00, float -0.000000e+00>, [[X:%.*]]
>> +; ANY-NEXT: [[EXP2:%.*]] = call <2 x float>
>> @llvm.exp2.v2f32(<2 x float> [[MUL]])
>> +; ANY-NEXT: ret <2 x float> [[EXP2]]
>> ;
>> %retval = call <2 x float> @llvm.pow.v2f32(<2 x float>
>> <float 0.5, float 0.5>, <2 x float> %x)
>> ret <2 x float> %retval
>> @@ -169,7 +170,7 @@ define <2 x double> @test_simplify6v(<2
>>
>> define float @test_simplify7(float %x) {
>> ; ANY-LABEL: @test_simplify7(
>> -; ANY-NEXT: [[SQRTF:%.*]] = call float @sqrtf(float
>> [[X:%.*]]) [[NUW_RO:#[0-9]+]]
>> +; ANY-NEXT: [[SQRTF:%.*]] = call float @sqrtf(float
>> [[X:%.*]]) [[NUW_RO]]
>> ; ANY-NEXT: [[ABS:%.*]] = call float @llvm.fabs.f32(float
>> [[SQRTF]])
>> ; ANY-NEXT: [[ISINF:%.*]] = fcmp oeq float [[X]],
>> 0xFFF0000000000000
>> ; ANY-NEXT: [[TMP1:%.*]] = select i1 [[ISINF]], float
>> 0x7FF0000000000000, float [[ABS]]
>> @@ -330,7 +331,6 @@ define <2 x double> @pow_neg1_double_fas
>> ret <2 x double> %r
>> }
>>
>> -declare double @llvm.pow.f64(double %Val, double %Power)
>> define double @test_simplify17(double %x) {
>> ; ANY-LABEL: @test_simplify17(
>> ; ANY-NEXT: [[SQRT:%.*]] = call double
>> @llvm.sqrt.f64(double [[X:%.*]])
>>
>>
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>
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