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[GlobalISel] Simplify Select type cleanup using a ScopeExit. NFC. 

This lets us use more natural early-returns when selection fails.

llvm-svn: 296006
This commit is contained in:
Ahmed Bougacha 2017-02-23 19:17:24 +00:00
parent 29cf0c4318
commit 1b3339447d
1 changed files with 18 additions and 13 deletions
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31
llvm/lib/CodeGen/GlobalISel/InstructionSelect.cpp
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@ -12,6 +12,7 @@
#include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
@ -55,6 +56,13 @@ static void reportSelectionError(const MachineFunction &MF,
}
bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
const MachineRegisterInfo &MRI = MF.getRegInfo();
// No matter what happens, whether we successfully select the function or not,
// nothing is going to use the vreg types after us. Make sure they disappear.
auto ClearVRegTypesOnReturn =
make_scope_exit([&]() { MRI.getVRegToType().clear(); });
// If the ISel pipeline failed, do not bother running that pass.
if (MF.getProperties().hasProperty(
MachineFunctionProperties::Property::FailedISel))
@ -69,8 +77,6 @@ bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
// FIXME: freezeReservedRegs is now done in IRTranslator, but there are many
// other MF/MFI fields we need to initialize.
const MachineRegisterInfo &MRI = MF.getRegInfo();
#ifndef NDEBUG
// Check that our input is fully legal: we require the function to have the
// Legalized property, so it should be.
@ -90,7 +96,6 @@ bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
// Until then, keep track of the number of blocks to assert that we don't.
const size_t NumBlocks = MF.size();
bool Failed = false;
for (MachineBasicBlock *MBB : post_order(&MF)) {
if (MBB->empty())
continue;
@ -120,8 +125,8 @@ bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
// FIXME: It would be nice to dump all inserted instructions. It's
// not obvious how, esp. considering select() can insert after MI.
reportSelectionError(MF, &MI, "Cannot select");
Failed = true;
break;
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
return false;
}
// Dump the range of instructions that MI expanded into.
@ -150,8 +155,8 @@ bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
if (MI && !RC) {
if (TPC.isGlobalISelAbortEnabled())
reportSelectionError(MF, MI, "VReg has no regclass after selection");
Failed = true;
break;
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
return false;
} else if (!RC)
continue;
@ -160,18 +165,18 @@ bool InstructionSelect::runOnMachineFunction(MachineFunction &MF) {
if (TPC.isGlobalISelAbortEnabled())
reportSelectionError(
MF, MI, "VReg has explicit size different from class size");
Failed = true;
break;
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
return false;
}
}
MRI.getVRegToType().clear();
if (!TPC.isGlobalISelAbortEnabled() && (Failed || MF.size() != NumBlocks)) {
if (MF.size() != NumBlocks) {
if (TPC.isGlobalISelAbortEnabled())
reportSelectionError(MF, /*MI=*/nullptr,
"Inserting blocks is not supported yet");
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
return false;
}
assert(MF.size() == NumBlocks && "Inserting blocks is not supported yet");
// FIXME: Should we accurately track changes?
return true;