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GlobalISel: avoid looking too closely at PHIs when we bail. 

The function used to finish off PHIs by adding the relevant basic blocks can
fail if we're aborting and still don't actually have the needed
MachineBasicBlocks. So avoid trying in that case.

llvm-svn: 288727
This commit is contained in:
Tim Northover 2016-12-05 23:10:19 +00:00
parent 48ee418f88
commit 800638fd67
2 changed files with 31 additions and 9 deletions
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20
llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
View File

@ -678,8 +678,6 @@ void IRTranslator::finishPendingPhis() {
MIB.addMBB(BBToMBB[PI->getIncomingBlock(i)]);
}
}
PendingPHIs.clear();
}
bool IRTranslator::translate(const Instruction &Inst) {
@ -725,10 +723,9 @@ bool IRTranslator::translate(const Constant &C, unsigned Reg) {
}
void IRTranslator::finalizeFunction() {
finishPendingPhis();
// Release the memory used by the different maps we
// needed during the translation.
PendingPHIs.clear();
ValToVReg.clear();
FrameIndices.clear();
Constants.clear();
@ -758,6 +755,7 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &MF) {
if (!TPC->isGlobalISelAbortEnabled()) {
MIRBuilder.getMF().getProperties().set(
MachineFunctionProperties::Property::FailedISel);
finalizeFunction();
return false;
}
report_fatal_error("Unable to lower arguments");
@ -777,7 +775,7 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &MF) {
MIRBuilder.setMBB(MBB);
for (const Instruction &Inst: BB) {
bool Succeeded = translate(Inst);
Succeeded &= translate(Inst);
if (!Succeeded) {
if (TPC->isGlobalISelAbortEnabled())
reportTranslationError(Inst, "unable to translate instruction");
@ -787,11 +785,15 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &MF) {
}
}
finalizeFunction();
if (Succeeded) {
finishPendingPhis();
// Now that the MachineFrameInfo has been configured, no further changes to
// the reserved registers are possible.
MRI->freezeReservedRegs(MF);
// Now that the MachineFrameInfo has been configured, no further changes to
// the reserved registers are possible.
MRI->freezeReservedRegs(MF);
}
finalizeFunction();
return false;
}

20
llvm/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
View File

@ -36,4 +36,24 @@ define i128 @ABIi128(i128 %arg1) {
; FALLBACK-WITH-REPORT-OUT: fmov d0, #1.0
define [1 x double] @constant() {
ret [1 x double] [double 1.0]
}
; The key problem here is that we may fail to create an MBB referenced by a
; PHI. If so, we cannot complete the G_PHI and mustn't try or bad things
; happen.
; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for pending_phis
define i32 @pending_phis(i1 %tst, i32 %val, i32* %addr) {
br i1 %tst, label %true, label %false
end:
%res = phi i32 [%val, %true], [42, %false]
ret i32 %res
true:
store atomic i32 42, i32* %addr seq_cst, align 4
br label %end
false:
br label %end
}