[llvm] r310025 - [InstCombine] Move the call to foldSelectICmpAnd into foldSelectInstWithICmp. NFCI
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 3 22:12:37 PDT 2017
Author: ctopper
Date: Thu Aug 3 22:12:37 2017
New Revision: 310025
URL: http://llvm.org/viewvc/llvm-project?rev=310025&view=rev
Log:
[InstCombine] Move the call to foldSelectICmpAnd into foldSelectInstWithICmp. NFCI
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=310025&r1=310024&r2=310025&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Thu Aug 3 22:12:37 2017
@@ -594,9 +594,89 @@ canonicalizeMinMaxWithConstant(SelectIns
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::foldSelectIns
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(
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::visitSelectIn
}
}
- 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) {
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