llvm/lib/Target/AMDGPU/SIFixVGPRCopies.cpp
Stanislav Mekhanoshin f4866eec22 [AMDGPU] Add VGPR copies post regalloc fix pass
Regalloc creates COPY instructions which do not formally use VALU.
That results in v_mov instructions displaced after exec mask modification.
One pass which do it is SIOptimizeExecMasking, but potentially it can be
done by other passes too.

This patch adds a pass immediately after regalloc to add implicit exec
use operand to all VGPR copy instructions.

Differential Revision: https://reviews.llvm.org/D28874

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292956 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-24 17:46:17 +00:00

73 lines
1.9 KiB
C++

//===-- SIFixVGPRCopies.cpp - Fix VGPR Copies after regalloc --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief Add implicit use of exec to vector register copies.
///
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "AMDGPUSubtarget.h"
#include "SIInstrInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
using namespace llvm;
#define DEBUG_TYPE "si-fix-vgpr-copies"
namespace {
class SIFixVGPRCopies : public MachineFunctionPass {
public:
static char ID;
public:
SIFixVGPRCopies() : MachineFunctionPass(ID) {
initializeSIFixVGPRCopiesPass(*PassRegistry::getPassRegistry());
}
bool runOnMachineFunction(MachineFunction &MF) override;
StringRef getPassName() const override { return "SI Fix VGPR copies"; }
};
} // End anonymous namespace.
INITIALIZE_PASS(SIFixVGPRCopies, DEBUG_TYPE, "SI Fix VGPR copies", false, false)
char SIFixVGPRCopies::ID = 0;
char &llvm::SIFixVGPRCopiesID = SIFixVGPRCopies::ID;
bool SIFixVGPRCopies::runOnMachineFunction(MachineFunction &MF) {
const SISubtarget &ST = MF.getSubtarget<SISubtarget>();
const SIRegisterInfo *TRI = ST.getRegisterInfo();
const SIInstrInfo *TII = ST.getInstrInfo();
bool Changed = false;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
switch (MI.getOpcode()) {
case AMDGPU::COPY:
if (TII->isVGPRCopy(MI) && !MI.readsRegister(AMDGPU::EXEC, TRI)) {
MI.addOperand(MF,
MachineOperand::CreateReg(AMDGPU::EXEC, false, true));
DEBUG(dbgs() << "Add exec use to " << MI);
Changed = true;
}
break;
default:
break;
}
}
}
return Changed;
}