[llvm] r373261 - [InstCombine] Expand the simplification of log()
Evandro Menezes via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 30 13:52:21 PDT 2019
Author: evandro
Date: Mon Sep 30 13:52:21 2019
New Revision: 373261
URL: http://llvm.org/viewvc/llvm-project?rev=373261&view=rev
Log:
[InstCombine] Expand the simplification of log()
Expand the simplification of special cases of `log()` to include `log2()`
and `log10()` as well as intrinsics and more types.
Differential revision: https://reviews.llvm.org/D67199
Modified:
llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
llvm/trunk/test/Transforms/InstCombine/log-pow.ll
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=373261&r1=373260&r2=373261&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Mon Sep 30 13:52:21 2019
@@ -35,6 +35,7 @@
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/KnownBits.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/SizeOpts.h"
@@ -1457,9 +1458,7 @@ Value *LibCallSimplifier::replacePowWith
StringRef ExpName;
Intrinsic::ID ID;
Value *ExpFn;
- LibFunc LibFnFloat;
- LibFunc LibFnDouble;
- LibFunc LibFnLongDouble;
+ LibFunc LibFnFloat, LibFnDouble, LibFnLongDouble;
switch (LibFn) {
default:
@@ -1809,48 +1808,155 @@ Value *LibCallSimplifier::optimizeFMinFM
return B.CreateCall(F, { CI->getArgOperand(0), CI->getArgOperand(1) });
}
-Value *LibCallSimplifier::optimizeLog(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
+Value *LibCallSimplifier::optimizeLog(CallInst *Log, IRBuilder<> &B) {
+ Function *LogFn = Log->getCalledFunction();
+ AttributeList Attrs = LogFn->getAttributes();
+ StringRef LogNm = LogFn->getName();
+ Intrinsic::ID LogID = LogFn->getIntrinsicID();
+ Module *Mod = Log->getModule();
+ Type *Ty = Log->getType();
Value *Ret = nullptr;
- StringRef Name = Callee->getName();
- if (UnsafeFPShrink && hasFloatVersion(Name))
- Ret = optimizeUnaryDoubleFP(CI, B, true);
- if (!CI->isFast())
- return Ret;
- Value *Op1 = CI->getArgOperand(0);
- auto *OpC = dyn_cast<CallInst>(Op1);
+ if (UnsafeFPShrink && hasFloatVersion(LogNm))
+ Ret = optimizeUnaryDoubleFP(Log, B, true);
// The earlier call must also be 'fast' in order to do these transforms.
- if (!OpC || !OpC->isFast())
+ CallInst *Arg = dyn_cast<CallInst>(Log->getArgOperand(0));
+ if (!Log->isFast() || !Arg || !Arg->isFast() || !Arg->hasOneUse())
return Ret;
- // log(pow(x,y)) -> y*log(x)
- // This is only applicable to log, log2, log10.
- if (Name != "log" && Name != "log2" && Name != "log10")
+ LibFunc LogLb, ExpLb, Exp2Lb, Exp10Lb, PowLb;
+
+ // This is only applicable to log(), log2(), log10().
+ if (TLI->getLibFunc(LogNm, LogLb))
+ switch (LogLb) {
+ case LibFunc_logf:
+ LogID = Intrinsic::log;
+ ExpLb = LibFunc_expf;
+ Exp2Lb = LibFunc_exp2f;
+ Exp10Lb = LibFunc_exp10f;
+ PowLb = LibFunc_powf;
+ break;
+ case LibFunc_log:
+ LogID = Intrinsic::log;
+ ExpLb = LibFunc_exp;
+ Exp2Lb = LibFunc_exp2;
+ Exp10Lb = LibFunc_exp10;
+ PowLb = LibFunc_pow;
+ break;
+ case LibFunc_logl:
+ LogID = Intrinsic::log;
+ ExpLb = LibFunc_expl;
+ Exp2Lb = LibFunc_exp2l;
+ Exp10Lb = LibFunc_exp10l;
+ PowLb = LibFunc_powl;
+ break;
+ case LibFunc_log2f:
+ LogID = Intrinsic::log2;
+ ExpLb = LibFunc_expf;
+ Exp2Lb = LibFunc_exp2f;
+ Exp10Lb = LibFunc_exp10f;
+ PowLb = LibFunc_powf;
+ break;
+ case LibFunc_log2:
+ LogID = Intrinsic::log2;
+ ExpLb = LibFunc_exp;
+ Exp2Lb = LibFunc_exp2;
+ Exp10Lb = LibFunc_exp10;
+ PowLb = LibFunc_pow;
+ break;
+ case LibFunc_log2l:
+ LogID = Intrinsic::log2;
+ ExpLb = LibFunc_expl;
+ Exp2Lb = LibFunc_exp2l;
+ Exp10Lb = LibFunc_exp10l;
+ PowLb = LibFunc_powl;
+ break;
+ case LibFunc_log10f:
+ LogID = Intrinsic::log10;
+ ExpLb = LibFunc_expf;
+ Exp2Lb = LibFunc_exp2f;
+ Exp10Lb = LibFunc_exp10f;
+ PowLb = LibFunc_powf;
+ break;
+ case LibFunc_log10:
+ LogID = Intrinsic::log10;
+ ExpLb = LibFunc_exp;
+ Exp2Lb = LibFunc_exp2;
+ Exp10Lb = LibFunc_exp10;
+ PowLb = LibFunc_pow;
+ break;
+ case LibFunc_log10l:
+ LogID = Intrinsic::log10;
+ ExpLb = LibFunc_expl;
+ Exp2Lb = LibFunc_exp2l;
+ Exp10Lb = LibFunc_exp10l;
+ PowLb = LibFunc_powl;
+ break;
+ default:
+ return Ret;
+ }
+ else if (LogID == Intrinsic::log || LogID == Intrinsic::log2 ||
+ LogID == Intrinsic::log10) {
+ if (Ty->getScalarType()->isFloatTy()) {
+ ExpLb = LibFunc_expf;
+ Exp2Lb = LibFunc_exp2f;
+ Exp10Lb = LibFunc_exp10f;
+ PowLb = LibFunc_powf;
+ } else if (Ty->getScalarType()->isDoubleTy()) {
+ ExpLb = LibFunc_exp;
+ Exp2Lb = LibFunc_exp2;
+ Exp10Lb = LibFunc_exp10;
+ PowLb = LibFunc_pow;
+ } else
+ return Ret;
+ } else
return Ret;
IRBuilder<>::FastMathFlagGuard Guard(B);
- FastMathFlags FMF;
- FMF.setFast();
- B.setFastMathFlags(FMF);
+ B.setFastMathFlags(FastMathFlags::getFast());
+
+ Function *ArgFn = Arg->getCalledFunction();
+ StringRef ArgNm = ArgFn->getName();
+ Intrinsic::ID ArgID = ArgFn->getIntrinsicID();
+ LibFunc ArgLb = NotLibFunc;
+ TLI->getLibFunc(ArgNm, ArgLb);
+
+ // log(pow(x,y)) -> y*log(x)
+ if (ArgLb == PowLb || ArgID == Intrinsic::pow) {
+ Value *LogX =
+ Log->doesNotAccessMemory()
+ ? B.CreateCall(Intrinsic::getDeclaration(Mod, LogID, Ty),
+ Arg->getOperand(0), "log")
+ : emitUnaryFloatFnCall(Arg->getOperand(0), LogNm, B, Attrs);
+ Value *MulY = B.CreateFMul(Arg->getArgOperand(1), LogX, "mul");
+ // Since pow() may have side effects, e.g. errno,
+ // dead code elimination may not be trusted to remove it.
+ substituteInParent(Arg, MulY);
+ return MulY;
+ }
+ // log(exp{,2,10}(y)) -> y*log({e,2,10})
+ // TODO: There is no exp10() intrinsic yet.
+ else if (ArgLb == ExpLb || ArgLb == Exp2Lb || ArgLb == Exp10Lb ||
+ ArgID == Intrinsic::exp || ArgID == Intrinsic::exp2) {
+ Constant *Eul;
+ if (ArgLb == ExpLb || ArgID == Intrinsic::exp)
+ Eul = ConstantFP::get(Log->getType(), M_E);
+ else if (ArgLb == Exp2Lb || ArgID == Intrinsic::exp2)
+ Eul = ConstantFP::get(Log->getType(), 2.0);
+ else
+ Eul = ConstantFP::get(Log->getType(), 10.0);
+ Value *LogE = Log->doesNotAccessMemory()
+ ? B.CreateCall(Intrinsic::getDeclaration(Mod, LogID, Ty),
+ Eul, "log")
+ : emitUnaryFloatFnCall(Eul, LogNm, B, Attrs);
+ Value *MulY = B.CreateFMul(Arg->getArgOperand(0), LogE, "mul");
+ // Since exp() may have side effects, e.g. errno,
+ // dead code elimination may not be trusted to remove it.
+ substituteInParent(Arg, MulY);
+ return MulY;
+ }
- LibFunc Func;
- Function *F = OpC->getCalledFunction();
- if (F && ((TLI->getLibFunc(F->getName(), Func) && TLI->has(Func) &&
- Func == LibFunc_pow) || F->getIntrinsicID() == Intrinsic::pow))
- return B.CreateFMul(OpC->getArgOperand(1),
- emitUnaryFloatFnCall(OpC->getOperand(0), Callee->getName(), B,
- Callee->getAttributes()), "mul");
-
- // log(exp2(y)) -> y*log(2)
- if (F && Name == "log" && TLI->getLibFunc(F->getName(), Func) &&
- TLI->has(Func) && Func == LibFunc_exp2)
- return B.CreateFMul(
- OpC->getArgOperand(0),
- emitUnaryFloatFnCall(ConstantFP::get(CI->getType(), 2.0),
- Callee->getName(), B, Callee->getAttributes()),
- "logmul");
return Ret;
}
@@ -2801,11 +2907,21 @@ Value *LibCallSimplifier::optimizeFloati
case LibFunc_sqrt:
case LibFunc_sqrtl:
return optimizeSqrt(CI, Builder);
+ case LibFunc_logf:
case LibFunc_log:
+ case LibFunc_logl:
+ case LibFunc_log10f:
case LibFunc_log10:
+ case LibFunc_log10l:
+ case LibFunc_log1pf:
case LibFunc_log1p:
+ case LibFunc_log1pl:
+ case LibFunc_log2f:
case LibFunc_log2:
+ case LibFunc_log2l:
+ case LibFunc_logbf:
case LibFunc_logb:
+ case LibFunc_logbl:
return optimizeLog(CI, Builder);
case LibFunc_tan:
case LibFunc_tanf:
@@ -2896,6 +3012,8 @@ Value *LibCallSimplifier::optimizeCall(C
case Intrinsic::exp2:
return optimizeExp2(CI, Builder);
case Intrinsic::log:
+ case Intrinsic::log2:
+ case Intrinsic::log10:
return optimizeLog(CI, Builder);
case Intrinsic::sqrt:
return optimizeSqrt(CI, Builder);
Modified: llvm/trunk/test/Transforms/InstCombine/log-pow.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/log-pow.ll?rev=373261&r1=373260&r2=373261&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/log-pow.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/log-pow.ll Mon Sep 30 13:52:21 2019
@@ -3,7 +3,7 @@
define double @log_pow(double %x, double %y) {
; CHECK-LABEL: @log_pow(
-; CHECK-NEXT: [[LOG1:%.*]] = call fast double @log(double [[X:%.*]]) #0
+; CHECK-NEXT: [[LOG1:%.*]] = call fast double @llvm.log.f64(double [[X:%.*]])
; CHECK-NEXT: [[MUL:%.*]] = fmul fast double [[LOG1]], [[Y:%.*]]
; CHECK-NEXT: ret double [[MUL]]
;
@@ -12,24 +12,22 @@ define double @log_pow(double %x, double
ret double %log
}
-; FIXME: log10f() should also be simplified.
define float @log10f_powf(float %x, float %y) {
; CHECK-LABEL: @log10f_powf(
-; CHECK-NEXT: [[POW:%.*]] = call fast float @powf(float [[X:%.*]], float [[Y:%.*]])
-; CHECK-NEXT: [[LOG:%.*]] = call fast float @log10f(float [[POW]])
-; CHECK-NEXT: ret float [[LOG]]
+; CHECK-NEXT: [[LOG1:%.*]] = call fast float @llvm.log10.f32(float [[X:%.*]])
+; CHECK-NEXT: [[MUL:%.*]] = fmul fast float [[LOG1]], [[Y:%.*]]
+; CHECK-NEXT: ret float [[MUL]]
;
%pow = call fast float @powf(float %x, float %y)
- %log = call fast float @log10f(float %pow)
+ %log = call fast float @llvm.log10.f32(float %pow)
ret float %log
}
-; FIXME: Intrinsic log2() should also be simplified.
define <2 x double> @log2v_powv(<2 x double> %x, <2 x double> %y) {
; CHECK-LABEL: @log2v_powv(
-; CHECK-NEXT: [[POW:%.*]] = call fast <2 x double> @llvm.pow.v2f64(<2 x double> [[X:%.*]], <2 x double> [[Y:%.*]])
-; CHECK-NEXT: [[LOG:%.*]] = call fast <2 x double> @llvm.log2.v2f64(<2 x double> [[POW]])
-; CHECK-NEXT: ret <2 x double> [[LOG]]
+; CHECK-NEXT: [[LOG1:%.*]] = call fast <2 x double> @llvm.log2.v2f64(<2 x double> [[X:%.*]])
+; CHECK-NEXT: [[MUL:%.*]] = fmul fast <2 x double> [[LOG1]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x double> [[MUL]]
;
%pow = call fast <2 x double> @llvm.pow.v2f64(<2 x double> %x, <2 x double> %y)
%log = call fast <2 x double> @llvm.log2.v2f64(<2 x double> %pow)
@@ -58,39 +56,33 @@ define float @function_pointer(float ()*
ret float %log
}
-; FIXME: The call to exp2() should be removed.
-define double @log_exp2(double %x) {
-; CHECK-LABEL: @log_exp2(
-; CHECK-NEXT: [[EXP:%.*]] = call fast double @exp2(double [[X:%.*]])
-; CHECK-NEXT: [[LOGMUL:%.*]] = fmul fast double [[X]], 0x3FE62E42FEFA39EF
-; CHECK-NEXT: ret double [[LOGMUL]]
+define double @log10_exp(double %x) {
+; CHECK-LABEL: @log10_exp(
+; CHECK-NEXT: [[MUL:%.*]] = fmul fast double [[X:%.*]], 0x3FDBCB7B1526E50E
+; CHECK-NEXT: ret double [[MUL]]
;
- %exp = call fast double @exp2(double %x)
- %log = call fast double @log(double %exp)
+ %exp = call fast double @exp(double %x)
+ %log = call fast double @log10(double %exp)
ret double %log
}
-; FIXME: Intrinsic logf() should also be simplified.
define <2 x float> @logv_exp2v(<2 x float> %x) {
; CHECK-LABEL: @logv_exp2v(
-; CHECK-NEXT: [[EXP:%.*]] = call fast <2 x float> @llvm.exp2.v2f32(<2 x float> [[X:%.*]])
-; CHECK-NEXT: [[LOG:%.*]] = call fast <2 x float> @llvm.log.v2f32(<2 x float> [[EXP]])
-; CHECK-NEXT: ret <2 x float> [[LOG]]
+; CHECK-NEXT: [[MUL:%.*]] = fmul fast <2 x float> [[X:%.*]], <float 0x3FE62E4300000000, float 0x3FE62E4300000000>
+; CHECK-NEXT: ret <2 x float> [[MUL]]
;
%exp = call fast <2 x float> @llvm.exp2.v2f32(<2 x float> %x)
%log = call fast <2 x float> @llvm.log.v2f32(<2 x float> %exp)
ret <2 x float> %log
}
-; FIXME: log10f() should also be simplified.
-define float @log10f_exp2f(float %x) {
-; CHECK-LABEL: @log10f_exp2f(
-; CHECK-NEXT: [[EXP:%.*]] = call fast float @exp2f(float [[X:%.*]])
-; CHECK-NEXT: [[LOG:%.*]] = call fast float @log10f(float [[EXP]])
-; CHECK-NEXT: ret float [[LOG]]
+define float @log2f_exp10f(float %x) {
+; CHECK-LABEL: @log2f_exp10f(
+; CHECK-NEXT: [[MUL:%.*]] = fmul fast float [[X:%.*]], 0x400A934F00000000
+; CHECK-NEXT: ret float [[MUL]]
;
- %exp = call fast float @exp2f(float %x)
- %log = call fast float @log10f(float %exp)
+ %exp = call fast float @exp10f(float %x)
+ %log = call fast float @log2f(float %exp)
ret float %log
}
@@ -108,11 +100,13 @@ define double @log_exp2_not_fast(double
declare double @log(double) #0
declare float @logf(float) #0
declare <2 x float> @llvm.log.v2f32(<2 x float>)
-declare double @log2(double) #0
+declare float @log2f(float) #0
declare <2 x double> @llvm.log2.v2f64(<2 x double>)
-declare float @log10f(float) #0
-declare double @exp2(double)
-declare float @exp2f(float)
+declare double @log10(double) #0
+declare float @llvm.log10.f32(float)
+declare double @exp(double %x) #0
+declare double @exp2(double) #0
+declare float @exp10f(float) #0
declare <2 x float> @llvm.exp2.v2f32(<2 x float>)
declare double @pow(double, double) #0
declare float @powf(float, float) #0
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