[llvm-commits] [llvm] r104167 - /llvm/trunk/lib/CodeGen/RegAllocFast.cpp
Jakob Stoklund Olesen
stoklund at 2pi.dk
Wed May 19 14:36:05 PDT 2010
Author: stoklund
Date: Wed May 19 16:36:05 2010
New Revision: 104167
URL: http://llvm.org/viewvc/llvm-project?rev=104167&view=rev
Log:
Add support for partial redefs to the fast register allocator.
A partial redef now triggers a reload if required. Also don't add
<imp-def,dead> operands for physical superregisters.
Kill flags are still treated as full register kills, and <imp-use,kill> operands
are added for physical superregisters as before.
Modified:
llvm/trunk/lib/CodeGen/RegAllocFast.cpp
Modified: llvm/trunk/lib/CodeGen/RegAllocFast.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocFast.cpp?rev=104167&r1=104166&r2=104167&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocFast.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocFast.cpp Wed May 19 16:36:05 2010
@@ -200,14 +200,9 @@
void RAFast::addKillFlag(const LiveReg &LR) {
if (!LR.LastUse) return;
MachineOperand &MO = LR.LastUse->getOperand(LR.LastOpNum);
- if (MO.getReg() == LR.PhysReg) {
- if (MO.isDef())
- MO.setIsDead();
- else if (!LR.LastUse->isRegTiedToDefOperand(LR.LastOpNum))
+ if (MO.isUse() && !LR.LastUse->isRegTiedToDefOperand(LR.LastOpNum)) {
+ if (MO.getReg() == LR.PhysReg)
MO.setIsKill();
- } else {
- if (MO.isDef())
- LR.LastUse->addRegisterDead(LR.PhysReg, TRI, true);
else
LR.LastUse->addRegisterKilled(LR.PhysReg, TRI, true);
}
@@ -513,6 +508,7 @@
bool New;
tie(LRI, New) = LiveVirtRegs.insert(std::make_pair(VirtReg, LiveReg()));
LiveReg &LR = LRI->second;
+ bool PartialRedef = MI->getOperand(OpNum).getSubReg();
if (New) {
// If there is no hint, peek at the only use of this register.
if ((!Hint || !TargetRegisterInfo::isPhysicalRegister(Hint)) &&
@@ -524,7 +520,15 @@
Hint = DstReg;
}
allocVirtReg(MI, *LRI, Hint);
- } else if (LR.LastUse) {
+ // If this is only a partial redefinition, we must reload the other parts.
+ if (PartialRedef && MI->readsVirtualRegister(VirtReg)) {
+ const TargetRegisterClass *RC = MRI->getRegClass(VirtReg);
+ int FI = getStackSpaceFor(VirtReg, RC);
+ DEBUG(dbgs() << "Reloading for partial redef: %reg" << VirtReg << "\n");
+ TII->loadRegFromStackSlot(*MBB, MI, LR.PhysReg, FI, RC, TRI);
+ ++NumLoads;
+ }
+ } else if (LR.LastUse && !PartialRedef) {
// Redefining a live register - kill at the last use, unless it is this
// instruction defining VirtReg multiple times.
if (LR.LastUse != MI || LR.LastUse->getOperand(LR.LastOpNum).isUse())
@@ -593,20 +597,14 @@
// Handle subregister index.
MO.setReg(PhysReg ? TRI->getSubReg(PhysReg, MO.getSubReg()) : 0);
MO.setSubReg(0);
- if (MO.isUse()) {
- if (MO.isKill()) {
- MI->addRegisterKilled(PhysReg, TRI, true);
- return true;
- }
- return false;
- }
- // A subregister def implicitly defines the whole physreg.
- if (MO.isDead()) {
- MI->addRegisterDead(PhysReg, TRI, true);
+
+ // A kill flag implies killing the full register. Add corresponding super
+ // register kill.
+ if (MO.isKill()) {
+ MI->addRegisterKilled(PhysReg, TRI, true);
return true;
}
- MI->addRegisterDefined(PhysReg, TRI);
- return false;
+ return MO.isDead();
}
void RAFast::AllocateBasicBlock() {
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