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44b486ed78
Before this change, the SystemZ backend would use BRCL for all branches
and only consider shortening them to BRC when generating an object file.
E.g. a branch on equal would use the JGE alias of BRCL in assembly output,
but might be shortened to the JE alias of BRC in ELF output. This was
a useful first step, but it had two problems:
(1) The z assembler isn't traditionally supposed to perform branch shortening
or branch relaxation. We followed this rule by not relaxing branches
in assembler input, but that meant that generating assembly code and
then assembling it would not produce the same result as going directly
to object code; the former would give long branches everywhere, whereas
the latter would use short branches where possible.
(2) Other useful branches, like COMPARE AND BRANCH, do not have long forms.
We would need to do something else before supporting them.
(Although COMPARE AND BRANCH does not change the condition codes,
the plan is to model COMPARE AND BRANCH as a CC-clobbering instruction
during codegen, so that we can safely lower it to a separate compare
and long branch where necessary. This is not a valid transformation
for the assembler proper to make.)
This patch therefore moves branch relaxation to a pre-emit pass.
For now, calls are still shortened from BRASL to BRAS by the assembler,
although this too is not really the traditional behaviour.
The first test takes about 1.5s to run, and there are likely to be
more tests in this vein once further branch types are added. The feeling
on IRC was that 1.5s is a bit much for a single test, so I've restricted
it to SystemZ hosts for now.
The patch exposes (and fixes) some typos in the main CodeGen/SystemZ tests.
A later patch will remove the {{g}}s from that directory.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182274 91177308-0d34-0410-b5e6-96231b3b80d8
79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
//==- SystemZ.h - Top-Level Interface for SystemZ representation -*- C++ -*-==//
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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 contains the entry points for global functions defined in
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// the LLVM SystemZ backend.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SYSTEMZ_H
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#define SYSTEMZ_H
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#include "MCTargetDesc/SystemZMCTargetDesc.h"
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#include "llvm/Support/CodeGen.h"
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namespace llvm {
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class SystemZTargetMachine;
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class FunctionPass;
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namespace SystemZ {
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// Condition-code mask values.
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const unsigned CCMASK_0 = 1 << 3;
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const unsigned CCMASK_1 = 1 << 2;
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const unsigned CCMASK_2 = 1 << 1;
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const unsigned CCMASK_3 = 1 << 0;
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const unsigned CCMASK_ANY = CCMASK_0 | CCMASK_1 | CCMASK_2 | CCMASK_3;
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// Condition-code mask assignments for floating-point comparisons.
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const unsigned CCMASK_CMP_EQ = CCMASK_0;
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const unsigned CCMASK_CMP_LT = CCMASK_1;
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const unsigned CCMASK_CMP_GT = CCMASK_2;
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const unsigned CCMASK_CMP_UO = CCMASK_3;
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const unsigned CCMASK_CMP_NE = CCMASK_CMP_LT | CCMASK_CMP_GT;
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const unsigned CCMASK_CMP_LE = CCMASK_CMP_EQ | CCMASK_CMP_LT;
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const unsigned CCMASK_CMP_GE = CCMASK_CMP_EQ | CCMASK_CMP_GT;
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const unsigned CCMASK_CMP_O = CCMASK_ANY ^ CCMASK_CMP_UO;
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// Return true if Val fits an LLILL operand.
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static inline bool isImmLL(uint64_t Val) {
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return (Val & ~0x000000000000ffffULL) == 0;
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}
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// Return true if Val fits an LLILH operand.
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static inline bool isImmLH(uint64_t Val) {
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return (Val & ~0x00000000ffff0000ULL) == 0;
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}
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// Return true if Val fits an LLIHL operand.
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static inline bool isImmHL(uint64_t Val) {
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return (Val & ~0x00000ffff00000000ULL) == 0;
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}
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// Return true if Val fits an LLIHH operand.
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static inline bool isImmHH(uint64_t Val) {
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return (Val & ~0xffff000000000000ULL) == 0;
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}
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// Return true if Val fits an LLILF operand.
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static inline bool isImmLF(uint64_t Val) {
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return (Val & ~0x00000000ffffffffULL) == 0;
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}
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// Return true if Val fits an LLIHF operand.
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static inline bool isImmHF(uint64_t Val) {
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return (Val & ~0xffffffff00000000ULL) == 0;
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}
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}
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FunctionPass *createSystemZISelDag(SystemZTargetMachine &TM,
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CodeGenOpt::Level OptLevel);
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FunctionPass *createSystemZLongBranchPass(SystemZTargetMachine &TM);
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} // end namespace llvm;
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#endif
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