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