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Consider any instruction that modifies the stack pointer to be

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a scheduling region boundary.  This isn't necessary for
correctness; it helps with compile time, as it avoids the need
for data- and anti-dependencies from all spills and reloads on
the stack-pointer modification.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64255 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-02-10 23:29:38 +00:00
parent 9e64bbb322
commit bed353d016
1 changed files with 10 additions and 0 deletions
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10
lib/CodeGen/PostRASchedulerList.cpp
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@ -28,6 +28,7 @@
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
@ -221,6 +222,15 @@ static bool isSchedulingBoundary(const MachineInstr *MI,
if (MI->getDesc().isTerminator() || MI->isLabel())
return true;
// Don't attempt to schedule around any instruction that modifies
// a stack-oriented pointer, as it's unlikely to be profitable. This
// saves compile time, because it doesn't require every single
// stack slot reference to depend on the instruction that does the
// modification.
const TargetLowering &TLI = *MF.getTarget().getTargetLowering();
if (MI->modifiesRegister(TLI.getStackPointerRegisterToSaveRestore()))
return true;
return false;
}