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author | Stephen Hines <srhines@google.com> | 2014-07-21 00:45:20 -0700 |
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committer | Stephen Hines <srhines@google.com> | 2014-07-25 00:48:57 -0700 |
commit | cd81d94322a39503e4a3e87b6ee03d4fcb3465fb (patch) | |
tree | 81b7dd2bb4370a392f31d332a566c903b5744764 /lib/Transforms/InstCombine/InstCombineSelect.cpp | |
parent | 0c5f13c0c4499eaf42ab5e9e2ceabd4e20e36861 (diff) | |
download | external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.zip external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.tar.gz external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.tar.bz2 |
Update LLVM for rebase to r212749.
Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls
Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineSelect.cpp')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineSelect.cpp | 102 |
1 files changed, 83 insertions, 19 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp index 9a41e4b..06c9e29 100644 --- a/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -31,13 +31,18 @@ MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); if (!ICI) return SPF_UNKNOWN; - LHS = ICI->getOperand(0); - RHS = ICI->getOperand(1); + ICmpInst::Predicate Pred = ICI->getPredicate(); + Value *CmpLHS = ICI->getOperand(0); + Value *CmpRHS = ICI->getOperand(1); + Value *TrueVal = SI->getTrueValue(); + Value *FalseVal = SI->getFalseValue(); + + LHS = CmpLHS; + RHS = CmpRHS; // (icmp X, Y) ? X : Y - if (SI->getTrueValue() == ICI->getOperand(0) && - SI->getFalseValue() == ICI->getOperand(1)) { - switch (ICI->getPredicate()) { + if (TrueVal == CmpLHS && FalseVal == CmpRHS) { + switch (Pred) { default: return SPF_UNKNOWN; // Equality. case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_UGE: return SPF_UMAX; @@ -51,18 +56,35 @@ MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { } // (icmp X, Y) ? Y : X - if (SI->getTrueValue() == ICI->getOperand(1) && - SI->getFalseValue() == ICI->getOperand(0)) { - switch (ICI->getPredicate()) { - default: return SPF_UNKNOWN; // Equality. - case ICmpInst::ICMP_UGT: - case ICmpInst::ICMP_UGE: return SPF_UMIN; - case ICmpInst::ICMP_SGT: - case ICmpInst::ICMP_SGE: return SPF_SMIN; - case ICmpInst::ICMP_ULT: - case ICmpInst::ICMP_ULE: return SPF_UMAX; - case ICmpInst::ICMP_SLT: - case ICmpInst::ICMP_SLE: return SPF_SMAX; + if (TrueVal == CmpRHS && FalseVal == CmpLHS) { + switch (Pred) { + default: return SPF_UNKNOWN; // Equality. + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: return SPF_UMIN; + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: return SPF_SMIN; + case ICmpInst::ICMP_ULT: + case ICmpInst::ICMP_ULE: return SPF_UMAX; + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: return SPF_SMAX; + } + } + + if (ConstantInt *C1 = dyn_cast<ConstantInt>(CmpRHS)) { + if ((CmpLHS == TrueVal && match(FalseVal, m_Neg(m_Specific(CmpLHS)))) || + (CmpLHS == FalseVal && match(TrueVal, m_Neg(m_Specific(CmpLHS))))) { + + // ABS(X) ==> (X >s 0) ? X : -X and (X >s -1) ? X : -X + // NABS(X) ==> (X >s 0) ? -X : X and (X >s -1) ? -X : X + if (Pred == ICmpInst::ICMP_SGT && (C1->isZero() || C1->isMinusOne())) { + return (CmpLHS == TrueVal) ? SPF_ABS : SPF_NABS; + } + + // ABS(X) ==> (X <s 0) ? -X : X and (X <s 1) ? -X : X + // NABS(X) ==> (X <s 0) ? X : -X and (X <s 1) ? X : -X + if (Pred == ICmpInst::ICMP_SLT && (C1->isZero() || C1->isOne())) { + return (CmpLHS == FalseVal) ? SPF_ABS : SPF_NABS; + } } } @@ -365,7 +387,15 @@ 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 -static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal, +/// +/// 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, Value *FalseVal, InstCombiner::BuilderTy *Builder) { const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); @@ -384,6 +414,25 @@ static Value *foldSelectICmpAndOr(const 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) @@ -677,6 +726,22 @@ Instruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, } } } + + // ABS(ABS(X)) -> ABS(X) + // NABS(NABS(X)) -> NABS(X) + if (SPF1 == SPF2 && (SPF1 == SPF_ABS || SPF1 == SPF_NABS)) { + return ReplaceInstUsesWith(Outer, Inner); + } + + // ABS(NABS(X)) -> ABS(X) + // NABS(ABS(X)) -> NABS(X) + if ((SPF1 == SPF_ABS && SPF2 == SPF_NABS) || + (SPF1 == SPF_NABS && SPF2 == SPF_ABS)) { + SelectInst *SI = cast<SelectInst>(Inner); + Value *NewSI = Builder->CreateSelect( + SI->getCondition(), SI->getFalseValue(), SI->getTrueValue()); + return ReplaceInstUsesWith(Outer, NewSI); + } return nullptr; } @@ -981,7 +1046,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) { // TODO. // ABS(-X) -> ABS(X) - // ABS(ABS(X)) -> ABS(X) } // See if we can fold the select into a phi node if the condition is a select. |