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[InstCombine] Move the call to foldSelectICmpAnd into foldSelectInstWithICmp. NFCI

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llvm-svn: 310025
This commit is contained in:
Craig Topper 2017-08-04 05:12:37 +00:00
parent 0f297d09b1
commit 14179d8998
1 changed files with 80 additions and 80 deletions
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160
lib/Transforms/InstCombine/InstCombineSelect.cpp
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@ -594,9 +594,89 @@ canonicalizeMinMaxWithConstant(SelectInst &Sel, ICmpInst &Cmp,
return &Sel;
}
/// If one of the constants is zero (we know they can't both be) and we have an
/// icmp instruction with zero, and we have an 'and' with the non-constant value
/// and a power of two we can turn the select into a shift on the result of the
/// 'and'.
static Value *foldSelectICmpAnd(const SelectInst &SI, const ICmpInst *IC,
APInt TrueVal, APInt FalseVal,
InstCombiner::BuilderTy &Builder) {
if (!IC->isEquality() || !SI.getType()->isIntegerTy())
return nullptr;
if (!match(IC->getOperand(1), m_Zero()))
return nullptr;
ConstantInt *AndRHS;
Value *LHS = IC->getOperand(0);
if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
return nullptr;
// If both select arms are non-zero see if we have a select of the form
// 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
// for 'x ? 2^n : 0' and fix the thing up at the end.
APInt Offset(TrueVal.getBitWidth(), 0);
if (!TrueVal.isNullValue() && !FalseVal.isNullValue()) {
if ((TrueVal - FalseVal).isPowerOf2())
Offset = FalseVal;
else if ((FalseVal - TrueVal).isPowerOf2())
Offset = TrueVal;
else
return nullptr;
// Adjust TrueVal and FalseVal to the offset.
TrueVal -= Offset;
FalseVal -= Offset;
}
// Make sure the mask in the 'and' and one of the select arms is a power of 2.
if (!AndRHS->getValue().isPowerOf2() ||
(!TrueVal.isPowerOf2() && !FalseVal.isPowerOf2()))
return nullptr;
// Determine which shift is needed to transform result of the 'and' into the
// desired result.
const APInt &ValC = !TrueVal.isNullValue() ? TrueVal : FalseVal;
unsigned ValZeros = ValC.logBase2();
unsigned AndZeros = AndRHS->getValue().logBase2();
// If types don't match we can still convert the select by introducing a zext
// or a trunc of the 'and'. The trunc case requires that all of the truncated
// bits are zero, we can figure that out by looking at the 'and' mask.
if (AndZeros >= ValC.getBitWidth())
return nullptr;
Value *V = Builder.CreateZExtOrTrunc(LHS, SI.getType());
if (ValZeros > AndZeros)
V = Builder.CreateShl(V, ValZeros - AndZeros);
else if (ValZeros < AndZeros)
V = Builder.CreateLShr(V, AndZeros - ValZeros);
// Okay, now we know that everything is set up, we just don't know whether we
// have a icmp_ne or icmp_eq and whether the true or false val is the zero.
bool ShouldNotVal = !TrueVal.isNullValue();
ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
if (ShouldNotVal)
V = Builder.CreateXor(V, ValC);
// Apply an offset if needed.
if (!Offset.isNullValue())
V = Builder.CreateAdd(V, ConstantInt::get(V->getType(), Offset));
return V;
}
/// Visit a SelectInst that has an ICmpInst as its first operand.
Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
ICmpInst *ICI) {
Value *TrueVal = SI.getTrueValue();
Value *FalseVal = SI.getFalseValue();
if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal))
if (Value *V = foldSelectICmpAnd(SI, ICI, TrueValC->getValue(),
FalseValC->getValue(), Builder))
return replaceInstUsesWith(SI, V);
if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, Builder))
return NewSel;
@ -605,8 +685,6 @@ Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
ICmpInst::Predicate Pred = ICI->getPredicate();
Value *CmpLHS = ICI->getOperand(0);
Value *CmpRHS = ICI->getOperand(1);
Value *TrueVal = SI.getTrueValue();
Value *FalseVal = SI.getFalseValue();
// Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1
// and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1
@ -864,78 +942,6 @@ Instruction *InstCombiner::foldSPFofSPF(Instruction *Inner,
return nullptr;
}
/// If one of the constants is zero (we know they can't both be) and we have an
/// icmp instruction with zero, and we have an 'and' with the non-constant value
/// and a power of two we can turn the select into a shift on the result of the
/// 'and'.
static Value *foldSelectICmpAnd(const SelectInst &SI, APInt TrueVal,
APInt FalseVal,
InstCombiner::BuilderTy &Builder) {
const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
return nullptr;
if (!match(IC->getOperand(1), m_Zero()))
return nullptr;
ConstantInt *AndRHS;
Value *LHS = IC->getOperand(0);
if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
return nullptr;
// If both select arms are non-zero see if we have a select of the form
// 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
// for 'x ? 2^n : 0' and fix the thing up at the end.
APInt Offset(TrueVal.getBitWidth(), 0);
if (!TrueVal.isNullValue() && !FalseVal.isNullValue()) {
if ((TrueVal - FalseVal).isPowerOf2())
Offset = FalseVal;
else if ((FalseVal - TrueVal).isPowerOf2())
Offset = TrueVal;
else
return nullptr;
// Adjust TrueVal and FalseVal to the offset.
TrueVal -= Offset;
FalseVal -= Offset;
}
// Make sure the mask in the 'and' and one of the select arms is a power of 2.
if (!AndRHS->getValue().isPowerOf2() ||
(!TrueVal.isPowerOf2() && !FalseVal.isPowerOf2()))
return nullptr;
// Determine which shift is needed to transform result of the 'and' into the
// desired result.
const APInt &ValC = !TrueVal.isNullValue() ? TrueVal : FalseVal;
unsigned ValZeros = ValC.logBase2();
unsigned AndZeros = AndRHS->getValue().logBase2();
// If types don't match we can still convert the select by introducing a zext
// or a trunc of the 'and'. The trunc case requires that all of the truncated
// bits are zero, we can figure that out by looking at the 'and' mask.
if (AndZeros >= ValC.getBitWidth())
return nullptr;
Value *V = Builder.CreateZExtOrTrunc(LHS, SI.getType());
if (ValZeros > AndZeros)
V = Builder.CreateShl(V, ValZeros - AndZeros);
else if (ValZeros < AndZeros)
V = Builder.CreateLShr(V, AndZeros - ValZeros);
// Okay, now we know that everything is set up, we just don't know whether we
// have a icmp_ne or icmp_eq and whether the true or false val is the zero.
bool ShouldNotVal = !TrueVal.isNullValue();
ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
if (ShouldNotVal)
V = Builder.CreateXor(V, ValC);
// Apply an offset if needed.
if (!Offset.isNullValue())
V = Builder.CreateAdd(V, ConstantInt::get(V->getType(), Offset));
return V;
}
/// Turn select C, (X + Y), (X - Y) --> (X + (select C, Y, (-Y))).
/// This is even legal for FP.
static Instruction *foldAddSubSelect(SelectInst &SI,
@ -1262,12 +1268,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
}
}
if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal))
if (Value *V = foldSelectICmpAnd(SI, TrueValC->getValue(),
FalseValC->getValue(), Builder))
return replaceInstUsesWith(SI, V);
// See if we are selecting two values based on a comparison of the two values.
if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {