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Keep track of the call instructions whose clobber lists were skipped during fast

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register allocation.

Process all of the clobber lists at the end of the function, marking the
registers as used in MachineRegisterInfo.

This is necessary in case the calls clobber callee-saved registers (sic).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105473 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-06-04 18:08:29 +00:00
parent 8fa8e7fe95
commit 6de07178e1
1 changed files with 17 additions and 0 deletions
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17
lib/CodeGen/RegAllocFast.cpp
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@ -110,6 +110,11 @@ namespace {
// Allocatable - vector of allocatable physical registers.
BitVector Allocatable;
// SkippedInstrs - Descriptors of instructions whose clobber list was ignored
// because all registers were spilled. It is still necessary to mark all the
// clobbered registers as used by the function.
SmallPtrSet<const TargetInstrDesc*, 4> SkippedInstrs;
// isBulkSpilling - This flag is set when LiveRegMap will be cleared
// completely after spilling all live registers. LiveRegMap entries should
// not be erased.
@ -752,6 +757,10 @@ void RAFast::AllocateBasicBlock() {
DefOpEnd = VirtOpEnd;
DEBUG(dbgs() << " Spilling remaining registers before call.\n");
spillAll(MI);
// The imp-defs are skipped below, but we still need to mark those
// registers as used by the function.
SkippedInstrs.insert(&TID);
}
// Third scan.
@ -837,6 +846,14 @@ bool RAFast::runOnMachineFunction(MachineFunction &Fn) {
// Make sure the set of used physregs is closed under subreg operations.
MRI->closePhysRegsUsed(*TRI);
// Add the clobber lists for all the instructions we skipped earlier.
for (SmallPtrSet<const TargetInstrDesc*, 4>::const_iterator
I = SkippedInstrs.begin(), E = SkippedInstrs.end(); I != E; ++I)
if (const unsigned *Defs = (*I)->getImplicitDefs())
while (*Defs)
MRI->setPhysRegUsed(*Defs++);
SkippedInstrs.clear();
StackSlotForVirtReg.clear();
return true;
}