Recognize loads of arguments as re-materializable first. Therefore if isReallyTriviallyReMaterializable() returns true it doesn't confuse it as a "normal" re-materializable instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47520 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-02-23 01:44:27 +00:00
parent 2007173203
commit dd3465eed1

View File

@ -643,6 +643,31 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
const TargetInstrDesc &TID = MI->getDesc();
if (TID.isImplicitDef())
return true;
int FrameIdx = 0;
if (tii_->isLoadFromStackSlot(MI, FrameIdx) &&
mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx)) {
// This is a load from fixed stack slot. It can be rematerialized unless
// it's re-defined by a two-address instruction.
isLoad = true;
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
i != e; ++i) {
const VNInfo *VNI = *i;
if (VNI == ValNo)
continue;
unsigned DefIdx = VNI->def;
if (DefIdx == ~1U)
continue; // Dead val#.
MachineInstr *DefMI = (DefIdx == ~0u)
? NULL : getInstructionFromIndex(DefIdx);
if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg)) {
isLoad = false;
return false;
}
}
return true;
}
if (tii_->isTriviallyReMaterializable(MI)) {
isLoad = TID.isSimpleLoad();
@ -663,30 +688,7 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
return true;
}
int FrameIdx = 0;
if (!tii_->isLoadFromStackSlot(MI, FrameIdx) ||
!mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx))
return false;
// This is a load from fixed stack slot. It can be rematerialized unless it's
// re-defined by a two-address instruction.
isLoad = true;
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
i != e; ++i) {
const VNInfo *VNI = *i;
if (VNI == ValNo)
continue;
unsigned DefIdx = VNI->def;
if (DefIdx == ~1U)
continue; // Dead val#.
MachineInstr *DefMI = (DefIdx == ~0u)
? NULL : getInstructionFromIndex(DefIdx);
if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg)) {
isLoad = false;
return false;
}
}
return true;
return false;
}
/// isReMaterializable - Returns true if every definition of MI of every