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[InstSimplify] reduce code for min/max analysis; NFC 

This should probably be moved up to some common area eventually
when there's another user.
This commit is contained in:
Sanjay Patel 2020-08-03 15:31:24 -04:00
parent 6abd7e2e62
commit 20c71e55aa
1 changed files with 23 additions and 28 deletions
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51
llvm/lib/Analysis/InstructionSimplify.cpp
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@ -5208,6 +5208,16 @@ static Intrinsic::ID getMaxMinOpposite(Intrinsic::ID ID) {
}
}
static APInt getMaxMinLimit(Intrinsic::ID ID, unsigned BitWidth) {
switch (ID) {
case Intrinsic::smax: return APInt::getSignedMaxValue(BitWidth);
case Intrinsic::smin: return APInt::getSignedMinValue(BitWidth);
case Intrinsic::umax: return APInt::getMaxValue(BitWidth);
case Intrinsic::umin: return APInt::getMinValue(BitWidth);
default: llvm_unreachable("Unexpected intrinsic");
}
}
static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
const SimplifyQuery &Q) {
Intrinsic::ID IID = F->getIntrinsicID();
@ -5238,16 +5248,8 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
std::swap(Op0, Op1);
// Assume undef is the limit value.
if (isa<UndefValue>(Op1)) {
if (IID == Intrinsic::smax)
return ConstantInt::get(ReturnType, APInt::getSignedMaxValue(BitWidth));
if (IID == Intrinsic::smin)
return ConstantInt::get(ReturnType, APInt::getSignedMinValue(BitWidth));
if (IID == Intrinsic::umax)
return ConstantInt::get(ReturnType, APInt::getMaxValue(BitWidth));
if (IID == Intrinsic::umin)
return ConstantInt::get(ReturnType, APInt::getMinValue(BitWidth));
}
if (isa<UndefValue>(Op1))
return ConstantInt::get(ReturnType, getMaxMinLimit(IID, BitWidth));
auto hasSpecificOperand = [](IntrinsicInst *II, Value *V) {
return II->getOperand(0) == V || II->getOperand(1) == V;
@ -5272,25 +5274,18 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
}
const APInt *C;
if (!match(Op1, m_APIntAllowUndef(C)))
break;
if (match(Op1, m_APIntAllowUndef(C))) {
// Clamp to limit value. For example:
// umax(i8 %x, i8 255) --> 255
if (*C == getMaxMinLimit(IID, BitWidth))
return ConstantInt::get(ReturnType, *C);
// Clamp to limit value. For example:
// umax(i8 %x, i8 255) --> 255
if ((IID == Intrinsic::smax && C->isMaxSignedValue()) ||
(IID == Intrinsic::smin && C->isMinSignedValue()) ||
(IID == Intrinsic::umax && C->isMaxValue()) ||
(IID == Intrinsic::umin && C->isMinValue()))
return ConstantInt::get(ReturnType, *C);
// If the constant op is the opposite of the limit value, the other must be
// larger/smaller or equal. For example:
// umin(i8 %x, i8 255) --> %x
if ((IID == Intrinsic::smax && C->isMinSignedValue()) ||
(IID == Intrinsic::smin && C->isMaxSignedValue()) ||
(IID == Intrinsic::umax && C->isMinValue()) ||
(IID == Intrinsic::umin && C->isMaxValue()))
return Op0;
// If the constant op is the opposite of the limit value, the other must
// be larger/smaller or equal. For example:
// umin(i8 %x, i8 255) --> %x
if (*C == getMaxMinLimit(getMaxMinOpposite(IID), BitWidth))
return Op0;
}
break;
}