diff options
author | Craig Topper <craig.topper@intel.com> | 2017-08-14 19:01:32 +0000 |
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committer | Craig Topper <craig.topper@intel.com> | 2017-08-14 19:01:32 +0000 |
commit | fcc217010fb837e17c2eb3d37811f4711ed7f428 (patch) | |
tree | ab6a19e89ee62cc017f1688f4e2d69e8d0c8f4e3 /lib/Analysis/CmpInstAnalysis.cpp | |
parent | 29130c26f7188c872a6f3a21213300823df7300f (diff) |
[InstCombine][InstSimplify] 'git add' two files that moved in r310869.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310870 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/CmpInstAnalysis.cpp')
-rw-r--r-- | lib/Analysis/CmpInstAnalysis.cpp | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/lib/Analysis/CmpInstAnalysis.cpp b/lib/Analysis/CmpInstAnalysis.cpp new file mode 100644 index 00000000000..c879b8729dc --- /dev/null +++ b/lib/Analysis/CmpInstAnalysis.cpp @@ -0,0 +1,137 @@ +//===- CmpInstAnalysis.cpp - Utils to help fold compares ---------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file holds routines to help analyse compare instructions +// and fold them into constants or other compare instructions +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/CmpInstAnalysis.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/PatternMatch.h" + +using namespace llvm; + +unsigned llvm::getICmpCode(const ICmpInst *ICI, bool InvertPred) { + ICmpInst::Predicate Pred = InvertPred ? ICI->getInversePredicate() + : ICI->getPredicate(); + switch (Pred) { + // False -> 0 + case ICmpInst::ICMP_UGT: return 1; // 001 + case ICmpInst::ICMP_SGT: return 1; // 001 + case ICmpInst::ICMP_EQ: return 2; // 010 + case ICmpInst::ICMP_UGE: return 3; // 011 + case ICmpInst::ICMP_SGE: return 3; // 011 + case ICmpInst::ICMP_ULT: return 4; // 100 + case ICmpInst::ICMP_SLT: return 4; // 100 + case ICmpInst::ICMP_NE: return 5; // 101 + case ICmpInst::ICMP_ULE: return 6; // 110 + case ICmpInst::ICMP_SLE: return 6; // 110 + // True -> 7 + default: + llvm_unreachable("Invalid ICmp predicate!"); + } +} + +Value *llvm::getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS, + CmpInst::Predicate &NewICmpPred) { + switch (Code) { + default: llvm_unreachable("Illegal ICmp code!"); + case 0: // False. + return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); + case 1: NewICmpPred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break; + case 2: NewICmpPred = ICmpInst::ICMP_EQ; break; + case 3: NewICmpPred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break; + case 4: NewICmpPred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break; + case 5: NewICmpPred = ICmpInst::ICMP_NE; break; + case 6: NewICmpPred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break; + case 7: // True. + return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1); + } + return nullptr; +} + +bool llvm::PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) { + return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) || + (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) || + (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1)); +} + +bool llvm::decomposeBitTestICmp(Value *LHS, Value *RHS, + CmpInst::Predicate &Pred, + Value *&X, APInt &Mask) { + const APInt *C; + if (!match(RHS, PatternMatch::m_APInt(C))) + return false; + + switch (Pred) { + default: + return false; + case ICmpInst::ICMP_SLT: + // X < 0 is equivalent to (X & SignMask) != 0. + if (!C->isNullValue()) + return false; + Mask = APInt::getSignMask(C->getBitWidth()); + Pred = ICmpInst::ICMP_NE; + break; + case ICmpInst::ICMP_SLE: + // X <= -1 is equivalent to (X & SignMask) != 0. + if (!C->isAllOnesValue()) + return false; + Mask = APInt::getSignMask(C->getBitWidth()); + Pred = ICmpInst::ICMP_NE; + break; + case ICmpInst::ICMP_SGT: + // X > -1 is equivalent to (X & SignMask) == 0. + if (!C->isAllOnesValue()) + return false; + Mask = APInt::getSignMask(C->getBitWidth()); + Pred = ICmpInst::ICMP_EQ; + break; + case ICmpInst::ICMP_SGE: + // X >= 0 is equivalent to (X & SignMask) == 0. + if (!C->isNullValue()) + return false; + Mask = APInt::getSignMask(C->getBitWidth()); + Pred = ICmpInst::ICMP_EQ; + break; + case ICmpInst::ICMP_ULT: + // X <u 2^n is equivalent to (X & ~(2^n-1)) == 0. + if (!C->isPowerOf2()) + return false; + Mask = -*C; + Pred = ICmpInst::ICMP_EQ; + break; + case ICmpInst::ICMP_ULE: + // X <=u 2^n-1 is equivalent to (X & ~(2^n-1)) == 0. + if (!(*C + 1).isPowerOf2()) + return false; + Mask = ~*C; + Pred = ICmpInst::ICMP_EQ; + break; + case ICmpInst::ICMP_UGT: + // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0. + if (!(*C + 1).isPowerOf2()) + return false; + Mask = ~*C; + Pred = ICmpInst::ICMP_NE; + break; + case ICmpInst::ICMP_UGE: + // X >=u 2^n is equivalent to (X & ~(2^n-1)) != 0. + if (!C->isPowerOf2()) + return false; + Mask = -*C; + Pred = ICmpInst::ICMP_NE; + break; + } + + X = LHS; + return true; +} |