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Target/X86/MC: Add an option for disabling arith relaxation, for my own testing

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purposes.

llvm-svn: 130438
This commit is contained in:
Daniel Dunbar 2011-04-28 21:23:31 +00:00
parent be5cb08cf8
commit a65f557314
1 changed files with 11 additions and 0 deletions
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11
lib/Target/X86/X86AsmBackend.cpp
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@ -21,6 +21,7 @@
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/Object/MachOFormat.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
@ -28,6 +29,13 @@
#include "llvm/Target/TargetAsmBackend.h"
using namespace llvm;
// Option to allow disabling arithmetic relaxation to workaround PR9807, which
// is useful when running bitwise comparison experiments on Darwin. We should be
// able to remove this once PR9807 is resolved.
static cl::opt<bool>
MCDisableArithRelaxation("mc-x86-disable-arith-relaxation",
cl::desc("Disable relaxation of arithmetic instruction for X86"));
static unsigned getFixupKindLog2Size(unsigned Kind) {
switch (Kind) {
default: assert(0 && "invalid fixup kind!");
@ -201,6 +209,9 @@ bool X86AsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
if (getRelaxedOpcodeBranch(Inst.getOpcode()) != Inst.getOpcode())
return true;
if (MCDisableArithRelaxation)
return false;
// Check if this instruction is ever relaxable.
if (getRelaxedOpcodeArith(Inst.getOpcode()) == Inst.getOpcode())
return false;