Assert that all trace candidate blocks have been visited by the PO.

When computing a trace, all the candidates for pred/succ must have been
visited. Filter out back-edges first, though. The PO traversal ignores
them.

Thanks to Andy for spotting this in review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160995 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-07-30 21:10:27 +00:00
parent ef6c76c984
commit 8e54ab5c76

View File

@ -214,15 +214,12 @@ MinInstrCountEnsemble::pickTracePred(const MachineBasicBlock *MBB) {
for (MachineBasicBlock::const_pred_iterator
I = MBB->pred_begin(), E = MBB->pred_end(); I != E; ++I) {
const MachineBasicBlock *Pred = *I;
const MachineTraceMetrics::TraceBlockInfo *PredTBI =
getDepthResources(Pred);
// Ignore invalidated predecessors. This never happens on the first scan,
// but if we rejected this predecessor earlier, it won't be revalidated.
if (!PredTBI)
continue;
// Don't consider predecessors in other loops.
if (getLoopFor(Pred) != CurLoop)
continue;
const MachineTraceMetrics::TraceBlockInfo *PredTBI =
getDepthResources(Pred);
assert(PredTBI && "Predecessor must be visited first");
// Pick the predecessor that would give this block the smallest InstrDepth.
unsigned Depth = PredTBI->InstrDepth + CurCount;
if (!Best || Depth < BestDepth)
@ -242,17 +239,15 @@ MinInstrCountEnsemble::pickTraceSucc(const MachineBasicBlock *MBB) {
for (MachineBasicBlock::const_succ_iterator
I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) {
const MachineBasicBlock *Succ = *I;
const MachineTraceMetrics::TraceBlockInfo *SuccTBI =
getHeightResources(Succ);
// Ignore invalidated successors.
if (!SuccTBI)
continue;
// Don't consider back-edges.
if (CurLoop && Succ == CurLoop->getHeader())
continue;
// Don't consider successors in other loops.
if (getLoopFor(Succ) != CurLoop)
continue;
const MachineTraceMetrics::TraceBlockInfo *SuccTBI =
getHeightResources(Succ);
assert(SuccTBI && "Successor must be visited first");
// Pick the successor that would give this block the smallest InstrHeight.
unsigned Height = SuccTBI->InstrHeight;
if (!Best || Height < BestHeight)