From d0207f44e28d1c2f2507707b19ab45fb8219eed4 Mon Sep 17 00:00:00 2001 From: dim Date: Thu, 27 Nov 2014 00:33:31 +0000 Subject: [PATCH] Pull in r222856 from upstream llvm trunk (by David Majnemer): Revert "Added inst combine transforms for single bit tests from Chris's note" This reverts commit r210006, it miscompiled libapr which is used in who knows how many projects. A test has been added to ensure that we don't regress again. This fixes a miscompilation in libapr, which caused problems in svnlite. --- .../InstCombine/InstCombineSelect.cpp | 29 +------------------ 1 file changed, 1 insertion(+), 28 deletions(-) diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index 06c9e290c6ea..a36cbe6db9ee 100644 --- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -387,15 +387,7 @@ static Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp, /// 1. The icmp predicate is inverted /// 2. The select operands are reversed /// 3. The magnitude of C2 and C1 are flipped -/// -/// This also tries to turn -/// --- Single bit tests: -/// if ((x & C) == 0) x |= C to x |= C -/// if ((x & C) != 0) x ^= C to x &= ~C -/// if ((x & C) == 0) x ^= C to x |= C -/// if ((x & C) != 0) x &= ~C to x &= ~C -/// if ((x & C) == 0) x &= ~C to nothing -static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal, +static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal, Value *FalseVal, InstCombiner::BuilderTy *Builder) { const ICmpInst *IC = dyn_cast(SI.getCondition()); @@ -414,25 +406,6 @@ static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal, return nullptr; const APInt *C2; - if (match(TrueVal, m_Specific(X))) { - // if ((X & C) != 0) X ^= C becomes X &= ~C - if (match(FalseVal, m_Xor(m_Specific(X), m_APInt(C2))) && C1 == C2) - return Builder->CreateAnd(X, ~(*C1)); - // if ((X & C) != 0) X &= ~C becomes X &= ~C - if (match(FalseVal, m_And(m_Specific(X), m_APInt(C2))) && *C1 == ~(*C2)) - return FalseVal; - } else if (match(FalseVal, m_Specific(X))) { - // if ((X & C) == 0) X ^= C becomes X |= C - if (match(TrueVal, m_Xor(m_Specific(X), m_APInt(C2))) && C1 == C2) - return Builder->CreateOr(X, *C1); - // if ((X & C) == 0) X &= ~C becomes nothing - if (match(TrueVal, m_And(m_Specific(X), m_APInt(C2))) && *C1 == ~(*C2)) - return X; - // if ((X & C) == 0) X |= C becomes X |= C - if (match(TrueVal, m_Or(m_Specific(X), m_APInt(C2))) && C1 == C2) - return TrueVal; - } - bool OrOnTrueVal = false; bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2))); if (!OrOnFalseVal)