Enforce stricter liveness rules for PHIs.

Verify that all paths from the entry block to a virtual register read
pass through a def. Enable this check even when MRI->isSSA() is false.

Verify that the live range of a virtual register is live out of all
predecessor blocks, even for PHI-values.

This requires that PHIElimination sometimes inserts IMPLICIT_DEF
instruction in predecessor blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159150 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2012-06-25 18:18:27 +00:00
parent 5984d2b31f
commit a4e6397fd9
2 changed files with 37 additions and 6 deletions
+11 -6
View File
@@ -1049,7 +1049,7 @@ void MachineVerifier::visitMachineFunctionAfter() {
// Now check liveness info if available
calcRegsRequired();
if (MRI->isSSA() && !MF->empty()) {
if (!MF->empty()) {
BBInfo &MInfo = MBBInfoMap[&MF->front()];
for (RegSet::iterator
I = MInfo.vregsRequired.begin(), E = MInfo.vregsRequired.end(); I != E;
@@ -1332,15 +1332,18 @@ void MachineVerifier::verifyLiveIntervals() {
++MFI;
continue;
}
// Is VNI a PHI-def in the current block?
bool IsPHI = VNI->isPHIDef() &&
VNI->def == LiveInts->getMBBStartIdx(MFI);
// Check that VNI is live-out of all predecessors.
for (MachineBasicBlock::const_pred_iterator PI = MFI->pred_begin(),
PE = MFI->pred_end(); PI != PE; ++PI) {
SlotIndex PEnd = LiveInts->getMBBEndIdx(*PI);
const VNInfo *PVNI = LI.getVNInfoBefore(PEnd);
if (VNI->isPHIDef() && VNI->def == LiveInts->getMBBStartIdx(MFI))
continue;
// All predecessors must have a live-out value.
if (!PVNI) {
report("Register not marked live out of predecessor", *PI);
*OS << "Valno #" << VNI->id << " live into BB#" << MFI->getNumber()
@@ -1349,12 +1352,14 @@ void MachineVerifier::verifyLiveIntervals() {
continue;
}
if (PVNI != VNI) {
// Only PHI-defs can take different predecessor values.
if (!IsPHI && PVNI != VNI) {
report("Different value live out of predecessor", *PI);
*OS << "Valno #" << PVNI->id << " live out of BB#"
<< (*PI)->getNumber() << '@' << PEnd
<< "\nValno #" << VNI->id << " live into BB#" << MFI->getNumber()
<< '@' << LiveInts->getMBBStartIdx(MFI) << " in " << LI << '\n';
<< '@' << LiveInts->getMBBStartIdx(MFI) << " in "
<< PrintReg(Reg) << ": " << LI << '\n';
}
}
if (&*MFI == EndMBB)