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[InstCombine] Reorder pow() transformations (NFC)

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Move the transformation from `powf(x, itofp(y))` to `powi(x, y)` to the
group of transformations related to the exponent.

llvm-svn: 365851
This commit is contained in:
Evandro Menezes 2019-07-12 00:33:49 +00:00
parent 94cd089f0d
commit b475507fec
1 changed files with 19 additions and 23 deletions
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42
lib/Transforms/Utils/SimplifyLibCalls.cpp
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@ -1236,7 +1236,7 @@ static Value *getPow(Value *InnerChain[33], unsigned Exp, IRBuilder<> &B) {
/// Use exp{,2}(x * y) for pow(exp{,2}(x), y);
/// exp2(n * x) for pow(2.0 ** n, x); exp10(x) for pow(10.0, x);
/// exp2(log2(C)*x) for pow(C,x).
/// exp2(log2(n) * x) for pow(n, x).
Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow, IRBuilder<> &B) {
Value *Base = Pow->getArgOperand(0), *Expo = Pow->getArgOperand(1);
AttributeList Attrs = Pow->getCalledFunction()->getAttributes();
@ -1348,7 +1348,7 @@ Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow, IRBuilder<> &B) {
return emitUnaryFloatFnCall(Expo, TLI, LibFunc_exp10, LibFunc_exp10f,
LibFunc_exp10l, B, Attrs);
// pow(C,x) -> exp2(log2(C)*x)
// pow(n, x) -> exp2(log2(n) * x)
if (Pow->hasOneUse() && Pow->hasApproxFunc() && Pow->hasNoNaNs() &&
Pow->hasNoInfs() && BaseF->isNormal() && !BaseF->isNegative()) {
Value *Log = nullptr;
@ -1474,21 +1474,6 @@ Value *LibCallSimplifier::optimizePow(CallInst *Pow, IRBuilder<> &B) {
if (Value *Exp = replacePowWithExp(Pow, B))
return Exp;
// powf(x, sitofp(e)) -> powi(x, e)
// powf(x, uitofp(e)) -> powi(x, e)
if (AllowApprox && (isa<SIToFPInst>(Expo) || isa<UIToFPInst>(Expo))) {
Value *IntExpo = cast<Instruction>(Expo)->getOperand(0);
Value *NewExpo = nullptr;
unsigned BitWidth = IntExpo->getType()->getPrimitiveSizeInBits();
if (isa<SIToFPInst>(Expo) && BitWidth == 32)
NewExpo = IntExpo;
else if (BitWidth < 32)
NewExpo = isa<SIToFPInst>(Expo) ? B.CreateSExt(IntExpo, B.getInt32Ty())
: B.CreateZExt(IntExpo, B.getInt32Ty());
if (NewExpo)
return createPowWithIntegerExponent(Base, NewExpo, M, B);
}
// Evaluate special cases related to the exponent.
// pow(x, -1.0) -> 1.0 / x
@ -1510,12 +1495,9 @@ Value *LibCallSimplifier::optimizePow(CallInst *Pow, IRBuilder<> &B) {
if (Value *Sqrt = replacePowWithSqrt(Pow, B))
return Sqrt;
if (!AllowApprox)
return Shrunk;
// pow(x, n) -> x * x * x * ...
const APFloat *ExpoF;
if (match(Expo, m_APFloat(ExpoF))) {
if (AllowApprox && match(Expo, m_APFloat(ExpoF))) {
// We limit to a max of 7 multiplications, thus the maximum exponent is 32.
// If the exponent is an integer+0.5 we generate a call to sqrt and an
// additional fmul.
@ -1565,7 +1547,7 @@ Value *LibCallSimplifier::optimizePow(CallInst *Pow, IRBuilder<> &B) {
}
APSInt IntExpo(32, /*isUnsigned=*/false);
// powf(x, C) -> powi(x, C) iff C is a constant signed integer value
// powf(x, n) -> powi(x, n) if n is a constant signed integer value
if (ExpoF->isInteger() &&
ExpoF->convertToInteger(IntExpo, APFloat::rmTowardZero, &Ignored) ==
APFloat::opOK) {
@ -1574,6 +1556,20 @@ Value *LibCallSimplifier::optimizePow(CallInst *Pow, IRBuilder<> &B) {
}
}
// powf(x, itofp(y)) -> powi(x, y)
if (AllowApprox && (isa<SIToFPInst>(Expo) || isa<UIToFPInst>(Expo))) {
Value *IntExpo = cast<Instruction>(Expo)->getOperand(0);
Value *NewExpo = nullptr;
unsigned BitWidth = IntExpo->getType()->getPrimitiveSizeInBits();
if (isa<SIToFPInst>(Expo) && BitWidth == 32)
NewExpo = IntExpo;
else if (BitWidth < 32)
NewExpo = isa<SIToFPInst>(Expo) ? B.CreateSExt(IntExpo, B.getInt32Ty())
: B.CreateZExt(IntExpo, B.getInt32Ty());
if (NewExpo)
return createPowWithIntegerExponent(Base, NewExpo, M, B);
}
return Shrunk;
}
@ -3160,4 +3156,4 @@ Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
FortifiedLibCallSimplifier::FortifiedLibCallSimplifier(
const TargetLibraryInfo *TLI, bool OnlyLowerUnknownSize)
: TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {}
: TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {}