[llvm] [InstCombine] Factor in op0's usages to decide leniency for one-use in foldComplexAndOrPatterns (PR #142666)
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Tue Jun 3 13:16:39 PDT 2025
https://github.com/AZero13 created https://github.com/llvm/llvm-project/pull/142666
If we can eliminate Op0 by replacing, which will happen if Op0 is one use, then we need not check if the other is one-use.
>From 2b1d040d9a8b7bf1e94d718baba2e78c99b51e9a Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Tue, 3 Jun 2025 16:02:02 -0400
Subject: [PATCH] [InstCombine] Factor in op0's usages to decide leniency for
one-use in foldComplexAndOrPatterns
If we can eliminate Op0 by replacing, which will happen if Op0 is one use, then we need not check if the other is one-use.
---
.../InstCombine/InstCombineAndOrXor.cpp | 89 ++++++++++++-------
1 file changed, 56 insertions(+), 33 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 2fb4bfecda8aa..a459be8fd7934 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2036,12 +2036,10 @@ static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
// (~(A | B) & C) | ... --> ...
// (~(A & B) | C) & ... --> ...
- // TODO: One use checks are conservative. We just need to check that a total
- // number of multiple used values does not exceed reduction
- // in operations.
if (matchNotOrAnd(Op0, m_Value(A), m_Value(B), m_Value(C), X)) {
// (~(A | B) & C) | (~(A | C) & B) --> (B ^ C) & ~A
// (~(A & B) | C) & (~(A & C) | B) --> ~((B ^ C) & A)
+
if (matchNotOrAnd(Op1, m_Specific(A), m_Specific(C), m_Specific(B), Dummy,
true)) {
Value *Xor = Builder.CreateXor(B, C);
@@ -2060,17 +2058,29 @@ static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
: BinaryOperator::CreateNot(Builder.CreateAnd(Xor, B));
}
+ bool Op0OneUse = Op0->hasOneUse();
+
// (~(A | B) & C) | ~(A | C) --> ~((B & C) | A)
// (~(A & B) | C) & ~(A & C) --> ~((B | C) & A)
- if (match(Op1, m_OneUse(m_Not(m_OneUse(
- m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
+ if (!Op0OneUse && match(Op1, m_OneUse(m_Not(m_OneUse(m_c_BinOp(
+ Opcode, m_Specific(A), m_Specific(C)))))))
+ return BinaryOperator::CreateNot(Builder.CreateBinOp(
+ Opcode, Builder.CreateBinOp(FlippedOpcode, B, C), A));
+
+ if (Op0OneUse &&
+ match(Op1, m_Not(m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))
return BinaryOperator::CreateNot(Builder.CreateBinOp(
Opcode, Builder.CreateBinOp(FlippedOpcode, B, C), A));
// (~(A | B) & C) | ~(B | C) --> ~((A & C) | B)
// (~(A & B) | C) & ~(B & C) --> ~((A | C) & B)
- if (match(Op1, m_OneUse(m_Not(m_OneUse(
- m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)))))))
+ if (!Op0OneUse && match(Op1, m_OneUse(m_Not(m_OneUse(m_c_BinOp(
+ Opcode, m_Specific(B), m_Specific(C)))))))
+ return BinaryOperator::CreateNot(Builder.CreateBinOp(
+ Opcode, Builder.CreateBinOp(FlippedOpcode, A, C), B));
+
+ if (Op0OneUse &&
+ match(Op1, m_Not(m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)))))
return BinaryOperator::CreateNot(Builder.CreateBinOp(
Opcode, Builder.CreateBinOp(FlippedOpcode, A, C), B));
@@ -2078,7 +2088,7 @@ static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
// Note, the pattern with swapped and/or is not handled because the
// result is more undefined than a source:
// (~(A & B) | C) & ~(C & (A ^ B)) --> (A ^ B ^ C) | ~(A | C) is invalid.
- if (Opcode == Instruction::Or && Op0->hasOneUse() &&
+ if (Opcode == Instruction::Or && Op0OneUse &&
match(Op1, m_OneUse(m_Not(m_CombineAnd(
m_Value(Y),
m_c_BinOp(Opcode, m_Specific(C),
@@ -2092,30 +2102,29 @@ static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
// (~A & B & C) | ... --> ...
// (~A | B | C) | ... --> ...
- // TODO: One use checks are conservative. We just need to check that a total
- // number of multiple used values does not exceed reduction
- // in operations.
- if (match(Op0,
- m_OneUse(m_c_BinOp(FlippedOpcode,
- m_BinOp(FlippedOpcode, m_Value(B), m_Value(C)),
- m_CombineAnd(m_Value(X), m_Not(m_Value(A)))))) ||
- match(Op0, m_OneUse(m_c_BinOp(
- FlippedOpcode,
- m_c_BinOp(FlippedOpcode, m_Value(C),
- m_CombineAnd(m_Value(X), m_Not(m_Value(A)))),
- m_Value(B))))) {
+ if (match(Op0, m_c_BinOp(FlippedOpcode,
+ m_BinOp(FlippedOpcode, m_Value(B), m_Value(C)),
+ m_CombineAnd(m_Value(X), m_Not(m_Value(A))))) ||
+ match(Op0,
+ m_c_BinOp(FlippedOpcode,
+ m_c_BinOp(FlippedOpcode, m_Value(C),
+ m_CombineAnd(m_Value(X), m_Not(m_Value(A)))),
+ m_Value(B)))) {
+ bool Op0OneUse = Op0->hasOneUse();
+
// X = ~A
// (~A & B & C) | ~(A | B | C) --> ~(A | (B ^ C))
// (~A | B | C) & ~(A & B & C) --> (~A | (B ^ C))
- if (match(Op1, m_OneUse(m_Not(m_c_BinOp(
- Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)),
- m_Specific(C))))) ||
- match(Op1, m_OneUse(m_Not(m_c_BinOp(
- Opcode, m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)),
- m_Specific(A))))) ||
- match(Op1, m_OneUse(m_Not(m_c_BinOp(
- Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)),
- m_Specific(B)))))) {
+ if ((match(Op1, m_Not(m_c_BinOp(
+ Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)),
+ m_Specific(C)))) ||
+ match(Op1, m_Not(m_c_BinOp(
+ Opcode, m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)),
+ m_Specific(A)))) ||
+ match(Op1, m_Not(m_c_BinOp(
+ Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)),
+ m_Specific(B))))) &&
+ (Op0OneUse || Op1->hasOneUse())) {
Value *Xor = Builder.CreateXor(B, C);
return (Opcode == Instruction::Or)
? BinaryOperator::CreateNot(Builder.CreateOr(Xor, A))
@@ -2124,16 +2133,30 @@ static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
// (~A & B & C) | ~(A | B) --> (C | ~B) & ~A
// (~A | B | C) & ~(A & B) --> (C & ~B) | ~A
- if (match(Op1, m_OneUse(m_Not(m_OneUse(
- m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)))))))
+ if (!Op0OneUse && match(Op1, m_OneUse(m_Not(m_OneUse(m_c_BinOp(
+ Opcode, m_Specific(A), m_Specific(B)))))))
return BinaryOperator::Create(
FlippedOpcode, Builder.CreateBinOp(Opcode, C, Builder.CreateNot(B)),
X);
+ if (Op0OneUse &&
+ match(Op1, m_Not(m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)))))
+ return BinaryOperator::Create(
+ FlippedOpcode, Builder.CreateBinOp(Opcode, C, Builder.CreateNot(B)),
+ X);
+
+ // (~A & B & C) | ~(A | C) --> (B | ~C) & ~A
+ // (~A | B | C) & ~(A & C) --> (B & ~C) | ~A
+ if (!Op0OneUse && match(Op1, m_OneUse(m_Not(m_OneUse(m_c_BinOp(
+ Opcode, m_Specific(A), m_Specific(C)))))))
+ return BinaryOperator::Create(
+ FlippedOpcode, Builder.CreateBinOp(Opcode, B, Builder.CreateNot(C)),
+ X);
+
// (~A & B & C) | ~(A | C) --> (B | ~C) & ~A
// (~A | B | C) & ~(A & C) --> (B & ~C) | ~A
- if (match(Op1, m_OneUse(m_Not(m_OneUse(
- m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
+ if (Op0OneUse &&
+ match(Op1, m_Not(m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))
return BinaryOperator::Create(
FlippedOpcode, Builder.CreateBinOp(Opcode, B, Builder.CreateNot(C)),
X);
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