mirror of
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0b8c9a80f2
into their new header subdirectory: include/llvm/IR. This matches the directory structure of lib, and begins to correct a long standing point of file layout clutter in LLVM. There are still more header files to move here, but I wanted to handle them in separate commits to make tracking what files make sense at each layer easier. The only really questionable files here are the target intrinsic tablegen files. But that's a battle I'd rather not fight today. I've updated both CMake and Makefile build systems (I think, and my tests think, but I may have missed something). I've also re-sorted the includes throughout the project. I'll be committing updates to Clang, DragonEgg, and Polly momentarily. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
97 lines
3.8 KiB
C++
97 lines
3.8 KiB
C++
//===- CmpInstAnalysis.cpp - Utils to help fold compares ---------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file holds routines to help analyse compare instructions
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// and fold them into constants or other compare instructions
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/Instructions.h"
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using namespace llvm;
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/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
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/// are carefully arranged to allow folding of expressions such as:
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///
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/// (A < B) | (A > B) --> (A != B)
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///
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/// Note that this is only valid if the first and second predicates have the
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/// same sign. Is illegal to do: (A u< B) | (A s> B)
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///
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/// Three bits are used to represent the condition, as follows:
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/// 0 A > B
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/// 1 A == B
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/// 2 A < B
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///
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/// <=> Value Definition
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/// 000 0 Always false
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/// 001 1 A > B
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/// 010 2 A == B
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/// 011 3 A >= B
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/// 100 4 A < B
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/// 101 5 A != B
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/// 110 6 A <= B
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/// 111 7 Always true
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///
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unsigned llvm::getICmpCode(const ICmpInst *ICI, bool InvertPred) {
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ICmpInst::Predicate Pred = InvertPred ? ICI->getInversePredicate()
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: ICI->getPredicate();
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switch (Pred) {
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// False -> 0
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case ICmpInst::ICMP_UGT: return 1; // 001
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case ICmpInst::ICMP_SGT: return 1; // 001
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case ICmpInst::ICMP_EQ: return 2; // 010
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case ICmpInst::ICMP_UGE: return 3; // 011
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case ICmpInst::ICMP_SGE: return 3; // 011
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case ICmpInst::ICMP_ULT: return 4; // 100
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case ICmpInst::ICMP_SLT: return 4; // 100
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case ICmpInst::ICMP_NE: return 5; // 101
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case ICmpInst::ICMP_ULE: return 6; // 110
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case ICmpInst::ICMP_SLE: return 6; // 110
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// True -> 7
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default:
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llvm_unreachable("Invalid ICmp predicate!");
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}
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}
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/// getICmpValue - This is the complement of getICmpCode, which turns an
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/// opcode and two operands into either a constant true or false, or the
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/// predicate for a new ICmp instruction. The sign is passed in to determine
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/// which kind of predicate to use in the new icmp instruction.
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/// Non-NULL return value will be a true or false constant.
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/// NULL return means a new ICmp is needed. The predicate for which is
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/// output in NewICmpPred.
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Value *llvm::getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
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CmpInst::Predicate &NewICmpPred) {
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switch (Code) {
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default: llvm_unreachable("Illegal ICmp code!");
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case 0: // False.
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return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
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case 1: NewICmpPred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break;
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case 2: NewICmpPred = ICmpInst::ICMP_EQ; break;
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case 3: NewICmpPred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break;
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case 4: NewICmpPred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break;
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case 5: NewICmpPred = ICmpInst::ICMP_NE; break;
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case 6: NewICmpPred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break;
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case 7: // True.
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return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
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}
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return NULL;
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}
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/// PredicatesFoldable - Return true if both predicates match sign or if at
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/// least one of them is an equality comparison (which is signless).
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bool llvm::PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
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return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
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(CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
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(CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
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}
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