From 3326ee444a8aa324c21e952204d7cf62916a9815 Mon Sep 17 00:00:00 2001 From: Suyog Sarda Date: Tue, 22 Jul 2014 18:30:54 +0000 Subject: [PATCH] Added InstCombine transform for pattern "(A & B) ^ (A ^ B) -> (A | B)" Patch idea by Ankit Jain ! Differential Revision: http://reviews.llvm.org/D4618 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213677 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../InstCombine/InstCombineAndOrXor.cpp | 8 ++++++++ test/Transforms/InstCombine/xor2.ll | 20 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index ef6a848357e..718cf29f184 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -2454,6 +2454,14 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) { if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } + // (A & B) ^ (A ^ B) -> (A | B) + if (match(Op0I, m_And(m_Value(A), m_Value(B))) && + match(Op1I, m_Xor(m_Specific(A), m_Specific(B)))) + return BinaryOperator::CreateOr(A, B); + // (A ^ B) ^ (A & B) -> (A | B) + if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) && + match(Op1I, m_And(m_Specific(A), m_Specific(B)))) + return BinaryOperator::CreateOr(A, B); } // (A | B)^(~A) -> (A | ~B) diff --git a/test/Transforms/InstCombine/xor2.ll b/test/Transforms/InstCombine/xor2.ll index e7b1b1bbda8..4ae50a140e1 100644 --- a/test/Transforms/InstCombine/xor2.ll +++ b/test/Transforms/InstCombine/xor2.ll @@ -105,3 +105,23 @@ define i32 @test8(i32 %a, i32 %b) #0 { ; CHECK-NEXT: %1 = xor i32 %b, -1 ; CHECK-NEXT: %xor = or i32 %a, %1 } + +; (A & B) ^ (A ^ B) -> (A | B) +define i32 @test9(i32 %b, i32 %c) { + %and = and i32 %b, %c + %xor = xor i32 %b, %c + %xor2 = xor i32 %and, %xor + ret i32 %xor2 +; CHECK-LABEL: @test9( +; CHECK-NEXT: %xor2 = or i32 %b, %c +} + +; (A ^ B) ^ (A & B) -> (A | B) +define i32 @test10(i32 %b, i32 %c) { + %xor = xor i32 %b, %c + %and = and i32 %b, %c + %xor2 = xor i32 %xor, %and + ret i32 %xor2 +; CHECK-LABEL: @test10( +; CHECK-NEXT: %xor2 = or i32 %b, %c +} -- 2.34.1