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[MachineVerifier] Analyze MachineMemOperands for mem-to-mem moves. 

Since the verifier will give false reports if it incorrectly thinks MI is
loading or storing using an FI, it is necessary to scan memoperands and
find out how the FI is used in the instruction. This should be relatively
rare.

Needed to make CodeGen/SystemZ/spill-01.ll pass, which now runs with this flag.

Reviewed by Quentin Colombet.

llvm-svn: 251620
This commit is contained in:
Jonas Paulsson 2015-10-29 08:28:35 +00:00
parent 3a063db203
commit 72640f1c9f
2 changed files with 26 additions and 7 deletions
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31
llvm/lib/CodeGen/MachineVerifier.cpp
View File

@ -992,15 +992,34 @@ MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) {
case MachineOperand::MO_FrameIndex:
if (LiveStks && LiveStks->hasInterval(MO->getIndex()) &&
LiveInts && !LiveInts->isNotInMIMap(MI)) {
LiveInterval &LI = LiveStks->getInterval(MO->getIndex());
int FI = MO->getIndex();
LiveInterval &LI = LiveStks->getInterval(FI);
SlotIndex Idx = LiveInts->getInstructionIndex(MI);
// For a memory-to-memory move, we don't know if MI is using
// this frame index for loading or storing, so check for
// liveness at reg-slot only in the simple load case.
bool stores = MI->mayStore();
bool simpleLoad = (MI->mayLoad() && !stores);
if (simpleLoad && !LI.liveAt(Idx.getRegSlot(true))) {
bool loads = MI->mayLoad();
// For a memory-to-memory move, we need to check if the frame
// index is used for storing or loading, by inspecting the
// memory operands.
if (stores && loads) {
for (auto *MMO : MI->memoperands()) {
const PseudoSourceValue *PSV = MMO->getPseudoValue();
if (PSV == nullptr) continue;
const FixedStackPseudoSourceValue *Value =
dyn_cast<FixedStackPseudoSourceValue>(PSV);
if (Value == nullptr) continue;
if (Value->getFrameIndex() != FI) continue;
if (MMO->isStore())
loads = false;
else
stores = false;
break;
}
if (loads == stores)
report("Missing fixed stack memoperand.", MI);
}
if (loads && !LI.liveAt(Idx.getRegSlot(true))) {
report("Instruction loads from dead spill slot", MO, MONum);
errs() << "Live stack: " << LI << '\n';
}

2
llvm/test/CodeGen/SystemZ/spill-01.ll
View File

@ -1,7 +1,7 @@
; Test spilling using MVC. The tests here assume z10 register pressure,
; without the high words being available.
;
; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z10 | FileCheck %s
; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z10 -verify-machineinstrs | FileCheck %s
declare void @foo()