summaryrefslogtreecommitdiff
path: root/lib/CodeGen/MachineCSE.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/CodeGen/MachineCSE.cpp')
-rw-r--r--lib/CodeGen/MachineCSE.cpp67
1 files changed, 39 insertions, 28 deletions
diff --git a/lib/CodeGen/MachineCSE.cpp b/lib/CodeGen/MachineCSE.cpp
index d228286d9db8..7da439caded4 100644
--- a/lib/CodeGen/MachineCSE.cpp
+++ b/lib/CodeGen/MachineCSE.cpp
@@ -13,7 +13,6 @@
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "machine-cse"
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/ScopedHashTable.h"
@@ -28,6 +27,8 @@
#include "llvm/Target/TargetInstrInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "machine-cse"
+
STATISTIC(NumCoalesces, "Number of copies coalesced");
STATISTIC(NumCSEs, "Number of common subexpression eliminated");
STATISTIC(NumPhysCSEs,
@@ -49,9 +50,9 @@ namespace {
initializeMachineCSEPass(*PassRegistry::getPassRegistry());
}
- virtual bool runOnMachineFunction(MachineFunction &MF);
+ bool runOnMachineFunction(MachineFunction &MF) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<AliasAnalysis>();
@@ -60,7 +61,7 @@ namespace {
AU.addPreserved<MachineDominatorTree>();
}
- virtual void releaseMemory() {
+ void releaseMemory() override {
ScopeMap.clear();
Exps.clear();
}
@@ -131,9 +132,24 @@ bool MachineCSE::PerformTrivialCoalescing(MachineInstr *MI,
unsigned SrcReg = DefMI->getOperand(1).getReg();
if (!TargetRegisterInfo::isVirtualRegister(SrcReg))
continue;
- if (DefMI->getOperand(0).getSubReg() || DefMI->getOperand(1).getSubReg())
+ if (DefMI->getOperand(0).getSubReg())
+ continue;
+ // FIXME: We should trivially coalesce subregister copies to expose CSE
+ // opportunities on instructions with truncated operands (see
+ // cse-add-with-overflow.ll). This can be done here as follows:
+ // if (SrcSubReg)
+ // RC = TRI->getMatchingSuperRegClass(MRI->getRegClass(SrcReg), RC,
+ // SrcSubReg);
+ // MO.substVirtReg(SrcReg, SrcSubReg, *TRI);
+ //
+ // The 2-addr pass has been updated to handle coalesced subregs. However,
+ // some machine-specific code still can't handle it.
+ // To handle it properly we also need a way find a constrained subregister
+ // class given a super-reg class and subreg index.
+ if (DefMI->getOperand(1).getSubReg())
continue;
- if (!MRI->constrainRegClass(SrcReg, MRI->getRegClass(Reg)))
+ const TargetRegisterClass *RC = MRI->getRegClass(Reg);
+ if (!MRI->constrainRegClass(SrcReg, RC))
continue;
DEBUG(dbgs() << "Coalescing: " << *DefMI);
DEBUG(dbgs() << "*** to: " << *MI);
@@ -214,7 +230,7 @@ bool MachineCSE::hasLivePhysRegDefUses(const MachineInstr *MI,
// Next, collect all defs into PhysDefs. If any is already in PhysRefs
// (which currently contains only uses), set the PhysUseDef flag.
PhysUseDef = false;
- MachineBasicBlock::const_iterator I = MI; I = llvm::next(I);
+ MachineBasicBlock::const_iterator I = MI; I = std::next(I);
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || !MO.isDef())
@@ -265,7 +281,7 @@ bool MachineCSE::PhysRegDefsReach(MachineInstr *CSMI, MachineInstr *MI,
}
CrossMBB = true;
}
- MachineBasicBlock::const_iterator I = CSMI; I = llvm::next(I);
+ MachineBasicBlock::const_iterator I = CSMI; I = std::next(I);
MachineBasicBlock::const_iterator E = MI;
MachineBasicBlock::const_iterator EE = CSMBB->end();
unsigned LookAheadLeft = LookAheadLimit;
@@ -310,8 +326,8 @@ bool MachineCSE::PhysRegDefsReach(MachineInstr *CSMI, MachineInstr *MI,
}
bool MachineCSE::isCSECandidate(MachineInstr *MI) {
- if (MI->isLabel() || MI->isPHI() || MI->isImplicitDef() ||
- MI->isKill() || MI->isInlineAsm() || MI->isDebugValue())
+ if (MI->isPosition() || MI->isPHI() || MI->isImplicitDef() || MI->isKill() ||
+ MI->isInlineAsm() || MI->isDebugValue())
return false;
// Ignore copies.
@@ -349,15 +365,11 @@ bool MachineCSE::isProfitableToCSE(unsigned CSReg, unsigned Reg,
TargetRegisterInfo::isVirtualRegister(Reg)) {
MayIncreasePressure = false;
SmallPtrSet<MachineInstr*, 8> CSUses;
- for (MachineRegisterInfo::use_nodbg_iterator I =MRI->use_nodbg_begin(CSReg),
- E = MRI->use_nodbg_end(); I != E; ++I) {
- MachineInstr *Use = &*I;
- CSUses.insert(Use);
+ for (MachineInstr &MI : MRI->use_nodbg_instructions(CSReg)) {
+ CSUses.insert(&MI);
}
- for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(Reg),
- E = MRI->use_nodbg_end(); I != E; ++I) {
- MachineInstr *Use = &*I;
- if (!CSUses.count(Use)) {
+ for (MachineInstr &MI : MRI->use_nodbg_instructions(Reg)) {
+ if (!CSUses.count(&MI)) {
MayIncreasePressure = true;
break;
}
@@ -388,11 +400,9 @@ bool MachineCSE::isProfitableToCSE(unsigned CSReg, unsigned Reg,
}
if (!HasVRegUse) {
bool HasNonCopyUse = false;
- for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(Reg),
- E = MRI->use_nodbg_end(); I != E; ++I) {
- MachineInstr *Use = &*I;
+ for (MachineInstr &MI : MRI->use_nodbg_instructions(Reg)) {
// Ignore copies.
- if (!Use->isCopyLike()) {
+ if (!MI.isCopyLike()) {
HasNonCopyUse = true;
break;
}
@@ -405,11 +415,9 @@ bool MachineCSE::isProfitableToCSE(unsigned CSReg, unsigned Reg,
// it unless the defined value is already used in the BB of the new use.
bool HasPHI = false;
SmallPtrSet<MachineBasicBlock*, 4> CSBBs;
- for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(CSReg),
- E = MRI->use_nodbg_end(); I != E; ++I) {
- MachineInstr *Use = &*I;
- HasPHI |= Use->isPHI();
- CSBBs.insert(Use->getParent());
+ for (MachineInstr &MI : MRI->use_nodbg_instructions(CSReg)) {
+ HasPHI |= MI.isPHI();
+ CSBBs.insert(MI.getParent());
}
if (!HasPHI)
@@ -513,7 +521,7 @@ bool MachineCSE::ProcessBlock(MachineBasicBlock *MBB) {
bool DoCSE = true;
unsigned NumDefs = MI->getDesc().getNumDefs() +
MI->getDesc().getNumImplicitDefs();
-
+
for (unsigned i = 0, e = MI->getNumOperands(); NumDefs && i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || !MO.isDef())
@@ -652,6 +660,9 @@ bool MachineCSE::PerformCSE(MachineDomTreeNode *Node) {
}
bool MachineCSE::runOnMachineFunction(MachineFunction &MF) {
+ if (skipOptnoneFunction(*MF.getFunction()))
+ return false;
+
TII = MF.getTarget().getInstrInfo();
TRI = MF.getTarget().getRegisterInfo();
MRI = &MF.getRegInfo();
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-04 09:48:40 +0000