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-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp72
-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineInternal.h3
2 files changed, 45 insertions, 30 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index a6280ec95a9..7e7a515bfc8 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1831,14 +1831,33 @@ static bool areInverseVectorBitmasks(Constant *C1, Constant *C2) {
/// We have an expression of the form (A & C) | (B & D). If A is a scalar or
/// vector composed of all-zeros or all-ones values and is the bitwise 'not' of
/// B, it can be used as the condition operand of a select instruction.
-static Value *getSelectCondition(Value *A, Value *B,
- InstCombiner::BuilderTy &Builder) {
- // If these are scalars or vectors of i1, A can be used directly.
+Value *InstCombiner::getSelectCondition(Value *A, Value *B) {
+ // Step 1: We may have peeked through bitcasts in the caller.
+ // Exit immediately if we don't have (vector) integer types.
Type *Ty = A->getType();
- if (match(A, m_Not(m_Specific(B))) && Ty->isIntOrIntVectorTy(1))
- return A;
+ if (!Ty->isIntOrIntVectorTy() || !B->getType()->isIntOrIntVectorTy())
+ return nullptr;
+
+ // Step 2: We need 0 or all-1's bitmasks.
+ if (ComputeNumSignBits(A) != Ty->getScalarSizeInBits())
+ return nullptr;
- // If A and B are sign-extended, look through the sexts to find the booleans.
+ // Step 3: If B is the 'not' value of A, we have our answer.
+ if (match(A, m_Not(m_Specific(B)))) {
+ // If these are scalars or vectors of i1, A can be used directly.
+ if (Ty->isIntOrIntVectorTy(1))
+ return A;
+ return Builder.CreateTrunc(A, CmpInst::makeCmpResultType(Ty));
+ }
+
+ // If both operands are constants, see if the constants are inverse bitmasks.
+ Constant *AConst, *BConst;
+ if (match(A, m_Constant(AConst)) && match(B, m_Constant(BConst)))
+ if (AConst == ConstantExpr::getNot(BConst))
+ return Builder.CreateZExtOrTrunc(A, CmpInst::makeCmpResultType(Ty));
+
+ // Look for more complex patterns. The 'not' op may be hidden behind various
+ // casts. Look through sexts and bitcasts to find the booleans.
Value *Cond;
Value *NotB;
if (match(A, m_SExt(m_Value(Cond))) &&
@@ -1854,36 +1873,29 @@ static Value *getSelectCondition(Value *A, Value *B,
if (!Ty->isVectorTy())
return nullptr;
- // If both operands are constants, see if the constants are inverse bitmasks.
- Constant *AC, *BC;
- if (match(A, m_Constant(AC)) && match(B, m_Constant(BC)) &&
- areInverseVectorBitmasks(AC, BC)) {
- return Builder.CreateZExtOrTrunc(AC, CmpInst::makeCmpResultType(Ty));
- }
-
// If both operands are xor'd with constants using the same sexted boolean
// operand, see if the constants are inverse bitmasks.
- if (match(A, (m_Xor(m_SExt(m_Value(Cond)), m_Constant(AC)))) &&
- match(B, (m_Xor(m_SExt(m_Specific(Cond)), m_Constant(BC)))) &&
+ // TODO: Use ConstantExpr::getNot()?
+ if (match(A, (m_Xor(m_SExt(m_Value(Cond)), m_Constant(AConst)))) &&
+ match(B, (m_Xor(m_SExt(m_Specific(Cond)), m_Constant(BConst)))) &&
Cond->getType()->isIntOrIntVectorTy(1) &&
- areInverseVectorBitmasks(AC, BC)) {
- AC = ConstantExpr::getTrunc(AC, CmpInst::makeCmpResultType(Ty));
- return Builder.CreateXor(Cond, AC);
+ areInverseVectorBitmasks(AConst, BConst)) {
+ AConst = ConstantExpr::getTrunc(AConst, CmpInst::makeCmpResultType(Ty));
+ return Builder.CreateXor(Cond, AConst);
}
return nullptr;
}
/// We have an expression of the form (A & C) | (B & D). Try to simplify this
/// to "A' ? C : D", where A' is a boolean or vector of booleans.
-static Value *matchSelectFromAndOr(Value *A, Value *C, Value *B, Value *D,
- InstCombiner::BuilderTy &Builder) {
+Value *InstCombiner::matchSelectFromAndOr(Value *A, Value *C, Value *B,
+ Value *D) {
// The potential condition of the select may be bitcasted. In that case, look
// through its bitcast and the corresponding bitcast of the 'not' condition.
Type *OrigType = A->getType();
A = peekThroughBitcast(A, true);
B = peekThroughBitcast(B, true);
-
- if (Value *Cond = getSelectCondition(A, B, Builder)) {
+ if (Value *Cond = getSelectCondition(A, B)) {
// ((bc Cond) & C) | ((bc ~Cond) & D) --> bc (select Cond, (bc C), (bc D))
// The bitcasts will either all exist or all not exist. The builder will
// not create unnecessary casts if the types already match.
@@ -2234,21 +2246,21 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
// 'or' that it is replacing.
if (Op0->hasOneUse() || Op1->hasOneUse()) {
// (Cond & C) | (~Cond & D) -> Cond ? C : D, and commuted variants.
- if (Value *V = matchSelectFromAndOr(A, C, B, D, Builder))
+ if (Value *V = matchSelectFromAndOr(A, C, B, D))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(A, C, D, B, Builder))
+ if (Value *V = matchSelectFromAndOr(A, C, D, B))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(C, A, B, D, Builder))
+ if (Value *V = matchSelectFromAndOr(C, A, B, D))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(C, A, D, B, Builder))
+ if (Value *V = matchSelectFromAndOr(C, A, D, B))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(B, D, A, C, Builder))
+ if (Value *V = matchSelectFromAndOr(B, D, A, C))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(B, D, C, A, Builder))
+ if (Value *V = matchSelectFromAndOr(B, D, C, A))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(D, B, A, C, Builder))
+ if (Value *V = matchSelectFromAndOr(D, B, A, C))
return replaceInstUsesWith(I, V);
- if (Value *V = matchSelectFromAndOr(D, B, C, A, Builder))
+ if (Value *V = matchSelectFromAndOr(D, B, C, A))
return replaceInstUsesWith(I, V);
}
}
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index a4d7fe8861b..431856c9e00 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -589,6 +589,9 @@ private:
Value *foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS, ICmpInst *RHS,
bool JoinedByAnd, Instruction &CxtI);
+ Value *matchSelectFromAndOr(Value *A, Value *B, Value *C, Value *D);
+ Value *getSelectCondition(Value *A, Value *B);
+
public:
/// Inserts an instruction \p New before instruction \p Old
///
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