From 410ce1c49a1be77fcd8eb0cb4a5e144637976b4a Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 23 Jul 2007 17:10:17 +0000 Subject: [PATCH] completely remove a transformation that is unsafe in the face of undefs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40439 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../Scalar/InstructionCombining.cpp | 36 ------------------- 1 file changed, 36 deletions(-) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 564b98165df..36e1fc2fe95 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -3870,42 +3870,6 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) { InsertNewInstBefore(BinaryOperator::createOr(V2, V3, "tmp"), I); return BinaryOperator::createAnd(V1, Or); } - - // (V1 & V3)|(V2 & ~V3) -> ((V1 ^ V2) & V3) ^ V2 - // Disable this transformations temporarily. This causes - // mis-compilation when V2 is undefined. - if (0 && isOnlyUse(Op0) && isOnlyUse(Op1)) { - // Try all combination of terms to find V3 and ~V3. - if (A->hasOneUse() && match(A, m_Not(m_Value(V3)))) { - if (V3 == B) - V1 = D, V2 = C; - else if (V3 == D) - V1 = B, V2 = C; - } - if (B->hasOneUse() && match(B, m_Not(m_Value(V3)))) { - if (V3 == A) - V1 = C, V2 = D; - else if (V3 == C) - V1 = A, V2 = D; - } - if (C->hasOneUse() && match(C, m_Not(m_Value(V3)))) { - if (V3 == B) - V1 = D, V2 = A; - else if (V3 == D) - V1 = B, V2 = A; - } - if (D->hasOneUse() && match(D, m_Not(m_Value(V3)))) { - if (V3 == A) - V1 = C, V2 = B; - else if (V3 == C) - V1 = A, V2 = B; - } - if (V1) { - A = InsertNewInstBefore(BinaryOperator::createXor(V1, V2, "tmp"), I); - A = InsertNewInstBefore(BinaryOperator::createAnd(A, V3, "tmp"), I); - return BinaryOperator::createXor(A, V2); - } - } } }