mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-24 22:32:47 +00:00
14c7036563
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209105 91177308-0d34-0410-b5e6-96231b3b80d8
66 lines
2.3 KiB
C++
66 lines
2.3 KiB
C++
//===-- CmpInstAnalysis.h - Utils to help fold compare insts ----*- C++ -*-===//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_TRANSFORMS_UTILS_CMPINSTANALYSIS_H
|
|
#define LLVM_TRANSFORMS_UTILS_CMPINSTANALYSIS_H
|
|
|
|
#include "llvm/IR/InstrTypes.h"
|
|
|
|
namespace llvm {
|
|
class ICmpInst;
|
|
class Value;
|
|
|
|
/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
|
|
/// are carefully arranged to allow folding of expressions such as:
|
|
///
|
|
/// (A < B) | (A > B) --> (A != B)
|
|
///
|
|
/// Note that this is only valid if the first and second predicates have the
|
|
/// same sign. Is illegal to do: (A u< B) | (A s> B)
|
|
///
|
|
/// Three bits are used to represent the condition, as follows:
|
|
/// 0 A > B
|
|
/// 1 A == B
|
|
/// 2 A < B
|
|
///
|
|
/// <=> Value Definition
|
|
/// 000 0 Always false
|
|
/// 001 1 A > B
|
|
/// 010 2 A == B
|
|
/// 011 3 A >= B
|
|
/// 100 4 A < B
|
|
/// 101 5 A != B
|
|
/// 110 6 A <= B
|
|
/// 111 7 Always true
|
|
///
|
|
unsigned getICmpCode(const ICmpInst *ICI, bool InvertPred = false);
|
|
|
|
/// getICmpValue - This is the complement of getICmpCode, which turns an
|
|
/// opcode and two operands into either a constant true or false, or the
|
|
/// predicate for a new ICmp instruction. The sign is passed in to determine
|
|
/// which kind of predicate to use in the new icmp instruction.
|
|
/// Non-NULL return value will be a true or false constant.
|
|
/// NULL return means a new ICmp is needed. The predicate for which is
|
|
/// output in NewICmpPred.
|
|
Value *getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
|
|
CmpInst::Predicate &NewICmpPred);
|
|
|
|
/// PredicatesFoldable - Return true if both predicates match sign or if at
|
|
/// least one of them is an equality comparison (which is signless).
|
|
bool PredicatesFoldable(CmpInst::Predicate p1, CmpInst::Predicate p2);
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif
|