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Do not try to rematerialize a value from a partial definition. 

I don't currently have a good testcase for this; will try to get one
tomorrow.  <rdar://problem/10032939>

llvm-svn: 138794
This commit is contained in:
Bob Wilson 2011-08-30 05:36:02 +00:00
parent b7abce9f8b
commit 358a5f6a72
1 changed files with 22 additions and 1 deletions
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23
llvm/lib/CodeGen/InlineSpiller.cpp
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@ -189,6 +189,20 @@ static unsigned isFullCopyOf(const MachineInstr *MI, unsigned Reg) {
return 0;
}
/// isFullDefOf - Return true if MI defines the full contents of a register.
/// Since this is in the context of spilling, it does not do anything special
/// for physical registers.
static bool isFullDefOf(const MachineInstr *MI, unsigned Reg) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || !MO.isDef() || MO.getSubReg())
continue;
if (MO.getReg() == Reg)
return true;
}
return false;
}
/// isSnippet - Identify if a live interval is a snippet that should be spilled.
/// It is assumed that SnipLI is a virtual register with the same original as
/// Edit->getReg().
@ -306,6 +320,7 @@ MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
MachineBasicBlock *SpillMBB = UseMBB;
unsigned SpillDepth = Loops.getLoopDepth(SpillMBB);
bool SeenOrigPHI = false; // Original PHI met.
bool SeenNonReloadDef = false;
do {
unsigned Reg;
@ -407,12 +422,18 @@ MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
}
// Potential remat candidate.
SeenNonReloadDef = true;
if (!isFullDefOf(MI, Reg)) {
DEBUG(dbgs() << " partial def " << PrintReg(Reg) << ':'
<< VNI->id << '@' << VNI->def << '\t' << *MI);
continue;
}
DEBUG(dbgs() << " def " << PrintReg(Reg) << ':'
<< VNI->id << '@' << VNI->def << '\t' << *MI);
SVI.DefMI = MI;
} while (!WorkList.empty());
if (SeenOrigPHI || SVI.DefMI)
if (SeenOrigPHI || SeenNonReloadDef)
SVI.AllDefsAreReloads = false;
DEBUG({