[PATCH] D113861: [InstSimplify] Fold A|B | (A^B) --> A|B
Mehrnoosh Heidarpour via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Sun Nov 14 13:06:01 PST 2021
MehrHeidar created this revision.
Herald added a subscriber: hiraditya.
MehrHeidar requested review of this revision.
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Herald added a subscriber: llvm-commits.
This patch adds the following fold opportunity:
A|B | (A^B) --> A|B
that is reported here : https://bugs.llvm.org/show_bug.cgi?id=52479
https://alive2.llvm.org/ce/z/33-My-
Test cases with base results are added in D113860 <https://reviews.llvm.org/D113860>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D113861
Files:
llvm/lib/Analysis/InstructionSimplify.cpp
Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2265,6 +2265,19 @@
match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
return Op0;
+ // (A | B) | (A ^ B) --> A | B
+ // (B | A) | (A ^ B) --> B | A
+ if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
+ match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
+ return Op0;
+
+ // Commute the outer 'or' operands.
+ // (A ^ B) | (A | B) --> A | B
+ // (A ^ B) | (B | A) --> B | A
+ if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
+ match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
+ return Op1;
+
// (~A & B) | ~(A | B) --> ~A
// (~A & B) | ~(B | A) --> ~A
// (B & ~A) | ~(A | B) --> ~A
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