llvm-6502/lib/Target/SystemZ/SystemZ.h
Richard Sandiford 8c20158fb0 [SystemZ] Use SRST to optimize memchr
SystemZTargetLowering::emitStringWrapper() previously loaded the character
into R0 before the loop and made R0 live on entry.  I'd forgotten that
allocatable registers weren't allowed to be live across blocks at this stage,
and it confused LiveVariables enough to cause a miscompilation of f3 in
memchr-02.ll.

This patch instead loads R0 in the loop and leaves LICM to hoist it
after RA.  This is actually what I'd tried originally, but I went for
the manual optimisation after noticing that R0 often wasn't being hoisted.
This bug forced me to go back and look at why, now fixed as r188774.

We should also try to optimize null checks so that they test the CC result
of the SRST directly.  The select between null and the SRST GPR result could
then usually be deleted as dead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188779 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-20 09:38:48 +00:00

97 lines
3.4 KiB
C++

//==- SystemZ.h - Top-Level Interface for SystemZ representation -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the entry points for global functions defined in
// the LLVM SystemZ backend.
//
//===----------------------------------------------------------------------===//
#ifndef SYSTEMZ_H
#define SYSTEMZ_H
#include "MCTargetDesc/SystemZMCTargetDesc.h"
#include "llvm/Support/CodeGen.h"
namespace llvm {
class SystemZTargetMachine;
class FunctionPass;
namespace SystemZ {
// Condition-code mask values.
const unsigned CCMASK_0 = 1 << 3;
const unsigned CCMASK_1 = 1 << 2;
const unsigned CCMASK_2 = 1 << 1;
const unsigned CCMASK_3 = 1 << 0;
const unsigned CCMASK_ANY = CCMASK_0 | CCMASK_1 | CCMASK_2 | CCMASK_3;
// Condition-code mask assignments for integer and floating-point
// comparisons.
const unsigned CCMASK_CMP_EQ = CCMASK_0;
const unsigned CCMASK_CMP_LT = CCMASK_1;
const unsigned CCMASK_CMP_GT = CCMASK_2;
const unsigned CCMASK_CMP_NE = CCMASK_CMP_LT | CCMASK_CMP_GT;
const unsigned CCMASK_CMP_LE = CCMASK_CMP_EQ | CCMASK_CMP_LT;
const unsigned CCMASK_CMP_GE = CCMASK_CMP_EQ | CCMASK_CMP_GT;
// Condition-code mask assignments for floating-point comparisons only.
const unsigned CCMASK_CMP_UO = CCMASK_3;
const unsigned CCMASK_CMP_O = CCMASK_ANY ^ CCMASK_CMP_UO;
// All condition-code values produced by comparisons.
const unsigned CCMASK_ICMP = CCMASK_0 | CCMASK_1 | CCMASK_2;
const unsigned CCMASK_FCMP = CCMASK_0 | CCMASK_1 | CCMASK_2 | CCMASK_3;
// Condition-code mask assignments for CS.
const unsigned CCMASK_CS_EQ = CCMASK_0;
const unsigned CCMASK_CS_NE = CCMASK_1;
const unsigned CCMASK_CS = CCMASK_0 | CCMASK_1;
// Condition-code mask assignments for a completed SRST loop.
const unsigned CCMASK_SRST_FOUND = CCMASK_1;
const unsigned CCMASK_SRST_NOTFOUND = CCMASK_2;
const unsigned CCMASK_SRST = CCMASK_1 | CCMASK_2;
// Return true if Val fits an LLILL operand.
static inline bool isImmLL(uint64_t Val) {
return (Val & ~0x000000000000ffffULL) == 0;
}
// Return true if Val fits an LLILH operand.
static inline bool isImmLH(uint64_t Val) {
return (Val & ~0x00000000ffff0000ULL) == 0;
}
// Return true if Val fits an LLIHL operand.
static inline bool isImmHL(uint64_t Val) {
return (Val & ~0x00000ffff00000000ULL) == 0;
}
// Return true if Val fits an LLIHH operand.
static inline bool isImmHH(uint64_t Val) {
return (Val & ~0xffff000000000000ULL) == 0;
}
// Return true if Val fits an LLILF operand.
static inline bool isImmLF(uint64_t Val) {
return (Val & ~0x00000000ffffffffULL) == 0;
}
// Return true if Val fits an LLIHF operand.
static inline bool isImmHF(uint64_t Val) {
return (Val & ~0xffffffff00000000ULL) == 0;
}
}
FunctionPass *createSystemZISelDag(SystemZTargetMachine &TM,
CodeGenOpt::Level OptLevel);
FunctionPass *createSystemZElimComparePass(SystemZTargetMachine &TM);
FunctionPass *createSystemZLongBranchPass(SystemZTargetMachine &TM);
} // end namespace llvm;
#endif