<div dir="ltr"><div dir="ltr">My bisection shows that this broke the clang stage 2 build:<div><a href="http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/13525">http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/13525</a><br></div><div><br></div><div>We end up with references to __unnamed_1 globals that are unresolved. I'll revert and get a reproducer.</div></div></div><br><div class="gmail_quote"><div dir="ltr">On Wed, Aug 29, 2018 at 11:00 AM Evandro Menezes via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: evandro<br>
Date: Wed Aug 29 10:59:34 2018<br>
New Revision: 340947<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=340947&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=340947&view=rev</a><br>
Log:<br>
[InstCombine] Expand the simplification of pow() into exp2()<br>
<br>
Generalize the simplification of `pow(2.0, y)` to `pow(2.0 ** n, y)` for all<br>
scalar and vector types.<br>
<br>
This improvement helps some benchmarks in SPEC CPU2000 and CPU2006, such as<br>
252.eon, 447.dealII, 453.povray. Otherwise, no significant regressions on<br>
x86-64 or A64.<br>
<br>
Differential revision: <a href="https://reviews.llvm.org/D49273" rel="noreferrer" target="_blank">https://reviews.llvm.org/D49273</a><br>
<br>
Modified:<br>
llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
llvm/trunk/test/Transforms/InstCombine/pow-1.ll<br>
<br>
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=340947&r1=340946&r2=340947&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=340947&r1=340946&r2=340947&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)<br>
+++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Wed Aug 29 10:59:34 2018<br>
@@ -13,6 +13,7 @@<br>
//===----------------------------------------------------------------------===//<br>
<br>
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"<br>
+#include "llvm/ADT/APSInt.h"<br>
#include "llvm/ADT/SmallString.h"<br>
#include "llvm/ADT/StringMap.h"<br>
#include "llvm/ADT/Triple.h"<br>
@@ -1183,12 +1184,13 @@ static Value *getPow(Value *InnerChain[3<br>
}<br>
<br>
/// Use exp{,2}(x * y) for pow(exp{,2}(x), y);<br>
-/// exp2(x) for pow(2.0, x); exp10(x) for pow(10.0, x).<br>
+/// exp2(n * x) for pow(2.0 ** n, x); exp10(x) for pow(10.0, x).<br>
Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow, IRBuilder<> &B) {<br>
Value *Base = Pow->getArgOperand(0), *Expo = Pow->getArgOperand(1);<br>
AttributeList Attrs = Pow->getCalledFunction()->getAttributes();<br>
Module *Mod = Pow->getModule();<br>
Type *Ty = Pow->getType();<br>
+ bool Ignored;<br>
<br>
// Evaluate special cases related to a nested function as the base.<br>
<br>
@@ -1232,10 +1234,28 @@ Value *LibCallSimplifier::replacePowWith<br>
<br>
// Evaluate special cases related to a constant base.<br>
<br>
- // pow(2.0, x) -> exp2(x)<br>
- if (match(Base, m_SpecificFP(2.0))) {<br>
- Value *Exp2 = Intrinsic::getDeclaration(Mod, Intrinsic::exp2, Ty);<br>
- return B.CreateCall(Exp2, Expo, "exp2");<br>
+ const APFloat *BaseF;<br>
+ if (!match(Pow->getArgOperand(0), m_APFloat(BaseF)))<br>
+ return nullptr;<br>
+<br>
+ // pow(2.0 ** n, x) -> exp2(n * x)<br>
+ APFloat BaseR = APFloat(1.0);<br>
+ BaseR.convert(BaseF->getSemantics(), APFloat::rmTowardZero, &Ignored);<br>
+ BaseR = BaseR / *BaseF;<br>
+ bool IsInteger = BaseF->isInteger(),<br>
+ IsReciprocal = BaseR.isInteger();<br>
+ const APFloat *NF = IsReciprocal ? &BaseR : BaseF;<br>
+ APSInt NI(64, false);<br>
+ if ((IsInteger || IsReciprocal) &&<br>
+ !NF->convertToInteger(NI, APFloat::rmTowardZero, &Ignored) &&<br>
+ NI > 1 && NI.isPowerOf2()) {<br>
+ double N = NI.logBase2() * (IsReciprocal ? -1.0 : 1.0);<br>
+ Value *FMul = B.CreateFMul(Expo, ConstantFP::get(Ty, N), "mul");<br>
+ if (Pow->doesNotAccessMemory())<br>
+ return B.CreateCall(Intrinsic::getDeclaration(Mod, Intrinsic::exp2, Ty),<br>
+ FMul, "exp2");<br>
+ else<br>
+ return emitUnaryFloatFnCall(FMul, TLI->getName(LibFunc_exp2), B, Attrs);<br>
}<br>
<br>
// pow(10.0, x) -> exp10(x)<br>
<br>
Modified: llvm/trunk/test/Transforms/InstCombine/pow-1.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/pow-1.ll?rev=340947&r1=340946&r2=340947&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/pow-1.ll?rev=340947&r1=340946&r2=340947&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/test/Transforms/InstCombine/pow-1.ll (original)<br>
+++ llvm/trunk/test/Transforms/InstCombine/pow-1.ll Wed Aug 29 10:59:34 2018<br>
@@ -16,6 +16,7 @@<br>
<br>
declare float @powf(float, float) nounwind readonly<br>
declare double @pow(double, double) nounwind readonly<br>
+declare double @llvm.pow.f64(double, double)<br>
declare <2 x float> @llvm.pow.v2f32(<2 x float>, <2 x float>) nounwind readonly<br>
declare <2 x double> @llvm.pow.v2f64(<2 x double>, <2 x double>) nounwind readonly<br>
<br>
@@ -57,18 +58,18 @@ define <2 x double> @test_simplify2v(<2<br>
<br>
define float @test_simplify3(float %x) {<br>
; ANY-LABEL: @test_simplify3(<br>
-; ANY-NEXT: [[EXP2:%.*]] = call float @llvm.exp2.f32(float [[X:%.*]])<br>
-; ANY-NEXT: ret float [[EXP2]]<br>
+; ANY-NEXT: [[EXP2F:%.*]] = call float @exp2f(float [[X:%.*]]) [[NUW_RO:#[0-9]+]]<br>
+; ANY-NEXT: ret float [[EXP2F]]<br>
;<br>
%retval = call float @powf(float 2.0, float %x)<br>
ret float %retval<br>
}<br>
<br>
-; TODO: Should result in exp2(-2.0 * x).<br>
define double @test_simplify3n(double %x) {<br>
; ANY-LABEL: @test_simplify3n(<br>
-; ANY-NEXT: [[RETVAL:%.*]] = call double @pow(double 2.500000e-01, double [[X:%.*]])<br>
-; ANY-NEXT: ret double [[RETVAL]]<br>
+; ANY-NEXT: [[MUL:%.*]] = fmul double [[X:%.*]], -2.000000e+00<br>
+; ANY-NEXT: [[EXP2:%.*]] = call double @exp2(double [[MUL]]) [[NUW_RO]]<br>
+; ANY-NEXT: ret double [[EXP2]]<br>
;<br>
%retval = call double @pow(double 0.25, double %x)<br>
ret double %retval<br>
@@ -83,11 +84,11 @@ define <2 x float> @test_simplify3v(<2 x<br>
ret <2 x float> %retval<br>
}<br>
<br>
-; TODO: Should result in exp2(2.0 * x).<br>
define <2 x double> @test_simplify3vn(<2 x double> %x) {<br>
; ANY-LABEL: @test_simplify3vn(<br>
-; 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:%.*]])<br>
-; ANY-NEXT: ret <2 x double> [[RETVAL]]<br>
+; ANY-NEXT: [[MUL:%.*]] = fmul <2 x double> [[X:%.*]], <double 2.000000e+00, double 2.000000e+00><br>
+; ANY-NEXT: [[EXP2:%.*]] = call <2 x double> @llvm.exp2.v2f64(<2 x double> [[MUL]])<br>
+; ANY-NEXT: ret <2 x double> [[EXP2]]<br>
;<br>
%retval = call <2 x double> @llvm.pow.v2f64(<2 x double> <double 4.0, double 4.0>, <2 x double> %x)<br>
ret <2 x double> %retval<br>
@@ -95,18 +96,18 @@ define <2 x double> @test_simplify3vn(<2<br>
<br>
define double @test_simplify4(double %x) {<br>
; ANY-LABEL: @test_simplify4(<br>
-; ANY-NEXT: [[EXP2:%.*]] = call double @llvm.exp2.f64(double [[X:%.*]])<br>
+; ANY-NEXT: [[EXP2:%.*]] = call double @exp2(double [[X:%.*]]) [[NUW_RO]]<br>
; ANY-NEXT: ret double [[EXP2]]<br>
;<br>
%retval = call double @pow(double 2.0, double %x)<br>
ret double %retval<br>
}<br>
<br>
-; TODO: Should result in exp2f(3.0 * x).<br>
define float @test_simplify4n(float %x) {<br>
; ANY-LABEL: @test_simplify4n(<br>
-; ANY-NEXT: [[RETVAL:%.*]] = call float @powf(float 8.000000e+00, float [[X:%.*]])<br>
-; ANY-NEXT: ret float [[RETVAL]]<br>
+; ANY-NEXT: [[MUL:%.*]] = fmul float [[X:%.*]], 3.000000e+00<br>
+; ANY-NEXT: [[EXP2F:%.*]] = call float @exp2f(float [[MUL]]) [[NUW_RO]]<br>
+; ANY-NEXT: ret float [[EXP2F]]<br>
;<br>
%retval = call float @powf(float 8.0, float %x)<br>
ret float %retval<br>
@@ -121,11 +122,11 @@ define <2 x double> @test_simplify4v(<2<br>
ret <2 x double> %retval<br>
}<br>
<br>
-; TODO: Should result in exp2f(-x).<br>
define <2 x float> @test_simplify4vn(<2 x float> %x) {<br>
; ANY-LABEL: @test_simplify4vn(<br>
-; 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:%.*]])<br>
-; ANY-NEXT: ret <2 x float> [[RETVAL]]<br>
+; ANY-NEXT: [[MUL:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[X:%.*]]<br>
+; ANY-NEXT: [[EXP2:%.*]] = call <2 x float> @llvm.exp2.v2f32(<2 x float> [[MUL]])<br>
+; ANY-NEXT: ret <2 x float> [[EXP2]]<br>
;<br>
%retval = call <2 x float> @llvm.pow.v2f32(<2 x float> <float 0.5, float 0.5>, <2 x float> %x)<br>
ret <2 x float> %retval<br>
@@ -169,7 +170,7 @@ define <2 x double> @test_simplify6v(<2<br>
<br>
define float @test_simplify7(float %x) {<br>
; ANY-LABEL: @test_simplify7(<br>
-; ANY-NEXT: [[SQRTF:%.*]] = call float @sqrtf(float [[X:%.*]]) [[NUW_RO:#[0-9]+]]<br>
+; ANY-NEXT: [[SQRTF:%.*]] = call float @sqrtf(float [[X:%.*]]) [[NUW_RO]]<br>
; ANY-NEXT: [[ABS:%.*]] = call float @llvm.fabs.f32(float [[SQRTF]])<br>
; ANY-NEXT: [[ISINF:%.*]] = fcmp oeq float [[X]], 0xFFF0000000000000<br>
; ANY-NEXT: [[TMP1:%.*]] = select i1 [[ISINF]], float 0x7FF0000000000000, float [[ABS]]<br>
@@ -330,7 +331,6 @@ define <2 x double> @pow_neg1_double_fas<br>
ret <2 x double> %r<br>
}<br>
<br>
-declare double @llvm.pow.f64(double %Val, double %Power)<br>
define double @test_simplify17(double %x) {<br>
; ANY-LABEL: @test_simplify17(<br>
; ANY-NEXT: [[SQRT:%.*]] = call double @llvm.sqrt.f64(double [[X:%.*]])<br>
<br>
<br>
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</blockquote></div>