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llvm-reduce: Do not try to delete frame instructions 

The verifier enforces these appearing as balanced pairs, so just
deleting one has no real chance of producing something valid.
This commit is contained in:
Matt Arsenault 2022-04-25 08:58:39 -04:00 committed by Matt Arsenault
parent 3939e99aae
commit 0b896b754e
2 changed files with 42 additions and 1 deletions
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24
llvm/test/tools/llvm-reduce/mir/remove-frame-destroy.mir Normal file
View File

@ -0,0 +1,24 @@
# REQUIRES: amdgpu-registered-target
# RUN: llvm-reduce --delta-passes=instructions -mtriple=amdgcn-amd-amdhsa --test FileCheck --test-arg --check-prefix=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t 2> %t.log
# RUN: FileCheck --check-prefix=RESULT %s < %t
# CHECK-INTERESTINGNESS: S_NOP 0
# RESULT: ADJCALLSTACKUP
# RESULT-NEXT: ADJCALLSTACKDOWN
# RESULT-NEXT: S_ENDPGM 0
---
name: frame_setup_destroy
tracksRegLiveness: true
machineFunctionInfo:
stackPtrOffsetReg: '$sgpr32'
body: |
bb.0:
S_NOP 0
ADJCALLSTACKUP 0, 0, implicit-def dead $scc, implicit-def $sgpr32, implicit $sgpr32
S_NOP 0
ADJCALLSTACKDOWN 0, 0, implicit-def dead $scc, implicit-def $sgpr32, implicit $sgpr32
S_ENDPGM 0
...

19
llvm/tools/llvm-reduce/deltas/ReduceInstructionsMIR.cpp
View File

@ -45,6 +45,21 @@ static Register getPrevDefOfRCInMBB(MachineBasicBlock &MBB,
return 0;
}
static bool shouldNotRemoveInstruction(const TargetInstrInfo &TII,
const MachineInstr &MI) {
if (MI.isTerminator())
return true;
// The MIR is almost certainly going to be invalid if frame instructions are
// deleted individually since they need to come in balanced pairs, so don't
// try to delete them.
if (MI.getOpcode() == TII.getCallFrameSetupOpcode() ||
MI.getOpcode() == TII.getCallFrameDestroyOpcode())
return true;
return false;
}
static void extractInstrFromFunction(Oracle &O, MachineFunction &MF) {
MachineDominatorTree MDT;
MDT.runOnMachineFunction(MF);
@ -52,12 +67,14 @@ static void extractInstrFromFunction(Oracle &O, MachineFunction &MF) {
auto MRI = &MF.getRegInfo();
SetVector<MachineInstr *> ToDelete;
const TargetSubtargetInfo &STI = MF.getSubtarget();
const TargetInstrInfo *TII = STI.getInstrInfo();
MachineInstr *TopMI = nullptr;
// Mark MIs for deletion according to some criteria.
for (auto &MBB : MF) {
for (auto &MI : MBB) {
if (MI.isTerminator())
if (shouldNotRemoveInstruction(*TII, MI))
continue;
if (MBB.isEntryBlock() && !TopMI) {
TopMI = &MI;