[llvm] [InstCombine] Loosen one-use restriction if common operand is constant (PR #79767)
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Mon Jan 29 16:07:04 PST 2024
https://github.com/AtariDreams updated https://github.com/llvm/llvm-project/pull/79767
>From 7f68505a7b3e92f45bf5bc0dffece80edb8ff117 Mon Sep 17 00:00:00 2001
From: Rose <83477269+AtariDreams at users.noreply.github.com>
Date: Sun, 28 Jan 2024 15:32:44 -0500
Subject: [PATCH 1/2] [InstCombine] pre-commit tests (NFC)
---
llvm/test/Transforms/InstCombine/xor-and-or.ll | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/llvm/test/Transforms/InstCombine/xor-and-or.ll b/llvm/test/Transforms/InstCombine/xor-and-or.ll
index feba47912b1dac5..c78f2335f5e14d6 100644
--- a/llvm/test/Transforms/InstCombine/xor-and-or.ll
+++ b/llvm/test/Transforms/InstCombine/xor-and-or.ll
@@ -241,4 +241,19 @@ define i1 @xor_and_or_negative_oneuse(i1 %c, i1 %x, i1 %y) {
ret i1 %r
}
+define i32 @xor_and_or_constant(i32 %X, i32 %Y, i32 %Z) {
+; CHECK-LABEL: @xor_and_or_constant(
+; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[X:%.*]], -1
+; CHECK-NEXT: [[TMP2:%.*]] = xor i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[TMP3:%.*]] = and i32 [[TMP2]], [[TMP1]]
+; CHECK-NEXT: ret i32 [[TMP3]]
+;
+ %1 = or i32 %X, %Y
+ %2 = or i32 %X, %Z
+ %3 = xor i32 %1, %2
+ %4 = xor i32 %X, -1
+ %5 = and i32 %3, %4
+ ret i32 %5
+}
+
declare void @use(i1)
>From 19760079f7822689c753949a0315a1c588750caa Mon Sep 17 00:00:00 2001
From: Rose <83477269+AtariDreams at users.noreply.github.com>
Date: Sun, 28 Jan 2024 13:30:29 -0500
Subject: [PATCH 2/2] [InstCombine] Loosen one-use restriction if common
operand is constant
---
.../InstCombine/InstCombineAndOrXor.cpp | 18 +++++++-----------
llvm/test/Transforms/InstCombine/xor-and-or.ll | 8 ++++----
2 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 5fd944a859ef098..bcdc92fa44e9086 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -4756,21 +4756,17 @@ Instruction *InstCombinerImpl::visitXor(BinaryOperator &I) {
return BinaryOperator::CreateNot(Builder.CreateAnd(Op0, B));
// (A | B) ^ (A | C) --> (B ^ C) & ~A -- There are 4 commuted variants.
- // TODO: Loosen one-use restriction if common operand is a constant.
- Value *D;
- if (match(Op0, m_OneUse(m_Or(m_Value(A), m_Value(B)))) &&
- match(Op1, m_OneUse(m_Or(m_Value(C), m_Value(D))))) {
- if (B == C || B == D)
- std::swap(A, B);
- if (A == C)
- std::swap(C, D);
- if (A == D) {
- Value *NotA = Builder.CreateNot(A);
- return BinaryOperator::CreateAnd(Builder.CreateXor(B, C), NotA);
+ if (match(Op0, m_c_Or(m_Value(A), m_Value(B))) &&
+ match(Op1, m_c_Or(m_Specific(A), m_Value(C)))) {
+ // Allow the tranformation to happen if A is one use or a constant.
+ if (A->hasOneUse() || match(A, m_ImmConstant())) {
+ return BinaryOperator::CreateAnd(Builder.CreateXor(B, C),
+ Builder.CreateNot(A));
}
}
// (A & B) ^ (A | C) --> A ? ~B : C -- There are 4 commuted variants.
+ Value *D;
if (I.getType()->isIntOrIntVectorTy(1) &&
match(Op0, m_OneUse(m_LogicalAnd(m_Value(A), m_Value(B)))) &&
match(Op1, m_OneUse(m_LogicalOr(m_Value(C), m_Value(D))))) {
diff --git a/llvm/test/Transforms/InstCombine/xor-and-or.ll b/llvm/test/Transforms/InstCombine/xor-and-or.ll
index c78f2335f5e14d6..7563efe9647e109 100644
--- a/llvm/test/Transforms/InstCombine/xor-and-or.ll
+++ b/llvm/test/Transforms/InstCombine/xor-and-or.ll
@@ -242,10 +242,10 @@ define i1 @xor_and_or_negative_oneuse(i1 %c, i1 %x, i1 %y) {
}
define i32 @xor_and_or_constant(i32 %X, i32 %Y, i32 %Z) {
-; CHECK-LABEL: @xor_and_or_constant(
-; CHECK-NEXT: [[TMP1:%.*]] = xor i32 [[X:%.*]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = xor i32 [[Y:%.*]], [[Z:%.*]]
-; CHECK-NEXT: [[TMP3:%.*]] = and i32 [[TMP2]], [[TMP1]]
+; CHECK-LABEL: @xor_and_or_c(
+; CHECK-NEXT: [[TMP1:%.*]] = or i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = or i32 [[X]], [[Z:%.*]]
+; CHECK-NEXT: [[TMP3:%.*]] = xor i32 [[TMP1]], [[TMP2]]
; CHECK-NEXT: ret i32 [[TMP3]]
;
%1 = or i32 %X, %Y
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