[llvm-commits] [llvm] r150288 - /llvm/trunk/lib/CodeGen/MachineLICM.cpp
Jakob Stoklund Olesen
stoklund at 2pi.dk
Fri Feb 10 16:44:19 PST 2012
Author: stoklund
Date: Fri Feb 10 18:44:19 2012
New Revision: 150288
URL: http://llvm.org/viewvc/llvm-project?rev=150288&view=rev
Log:
Allow Post-RA LICM to hoist reserved register reads.
When using register masks, registers like %rip are clobbered by the
register mask. LICM should still be able to hoist instructions reading
%rip from a loop containing calls.
Modified:
llvm/trunk/lib/CodeGen/MachineLICM.cpp
Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=150288&r1=150287&r2=150288&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Fri Feb 10 18:44:19 2012
@@ -68,6 +68,7 @@
MachineRegisterInfo *MRI;
const InstrItineraryData *InstrItins;
bool PreRegAlloc;
+ BitVector ReservedRegs;
// Various analyses that we use...
AliasAnalysis *AA; // Alias analysis info.
@@ -337,6 +338,8 @@
for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
E = TRI->regclass_end(); I != E; ++I)
RegLimit[(*I)->getID()] = TRI->getRegPressureLimit(*I, MF);
+ } else {
+ ReservedRegs = TRI->getReservedRegs(MF);
}
// Get our Loop information...
@@ -426,6 +429,9 @@
"Not expecting virtual register!");
if (!MO.isDef()) {
+ // Allow reserved register reads to be hoisted.
+ if (ReservedRegs.test(Reg))
+ continue;
if (Reg && (PhysRegDefs.test(Reg) || PhysRegClobbers.test(Reg)))
// If it's using a non-loop-invariant register, then it's obviously not
// safe to hoist.
@@ -531,6 +537,11 @@
const MachineOperand &MO = MI->getOperand(j);
if (!MO.isReg() || MO.isDef() || !MO.getReg())
continue;
+ // Allow hoisting of reserved register reads that aren't call preserved.
+ // For example %rip.
+ // IsLoopInvariantInst() already checks MRI->isConstantPhysReg().
+ if (ReservedRegs.test(MO.getReg()))
+ continue;
if (PhysRegDefs.test(MO.getReg()) ||
PhysRegClobbers.test(MO.getReg())) {
// If it's using a non-loop-invariant register, then it's obviously
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