[llvm-commits] [llvm] r131192 - /llvm/trunk/lib/CodeGen/InlineSpiller.cpp
Jakob Stoklund Olesen
stoklund at 2pi.dk
Wed May 11 11:25:10 PDT 2011
Author: stoklund
Date: Wed May 11 13:25:10 2011
New Revision: 131192
URL: http://llvm.org/viewvc/llvm-project?rev=131192&view=rev
Log:
Avoid hoisting spills when looking at a copy from another register that is also
about to be spilled.
This can only happen when two extra snippet registers are included in the spill,
and there is a copy between them. Hoisting the spill creates problems because
the hoist will mark the copy for later dead code elimination, and spilling the
second register will turn the copy into a spill.
<rdar://problem/9420853>
Modified:
llvm/trunk/lib/CodeGen/InlineSpiller.cpp
Modified: llvm/trunk/lib/CodeGen/InlineSpiller.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InlineSpiller.cpp?rev=131192&r1=131191&r2=131192&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/InlineSpiller.cpp (original)
+++ llvm/trunk/lib/CodeGen/InlineSpiller.cpp Wed May 11 13:25:10 2011
@@ -855,6 +855,7 @@
/// spillAroundUses - insert spill code around each use of Reg.
void InlineSpiller::spillAroundUses(unsigned Reg) {
+ DEBUG(dbgs() << "spillAroundUses " << PrintReg(Reg) << '\n');
LiveInterval &OldLI = LIS.getInterval(Reg);
// Iterate over instructions using Reg.
@@ -902,6 +903,12 @@
// Check for a sibling copy.
unsigned SibReg = isFullCopyOf(MI, Reg);
if (SibReg && isSibling(SibReg)) {
+ // This may actually be a copy between snippets.
+ if (isRegToSpill(SibReg)) {
+ DEBUG(dbgs() << "Found new snippet copy: " << *MI);
+ SnippetCopies.insert(MI);
+ continue;
+ }
if (Writes) {
// Hoist the spill of a sib-reg copy.
if (hoistSpill(OldLI, MI)) {
@@ -983,13 +990,15 @@
}
// Finally delete the SnippetCopies.
- for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Edit->getReg());
- MachineInstr *MI = RI.skipInstruction();) {
- assert(SnippetCopies.count(MI) && "Remaining use wasn't a snippet copy");
- // FIXME: Do this with a LiveRangeEdit callback.
- VRM.RemoveMachineInstrFromMaps(MI);
- LIS.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(RegsToSpill[i]);
+ MachineInstr *MI = RI.skipInstruction();) {
+ assert(SnippetCopies.count(MI) && "Remaining use wasn't a snippet copy");
+ // FIXME: Do this with a LiveRangeEdit callback.
+ VRM.RemoveMachineInstrFromMaps(MI);
+ LIS.RemoveMachineInstrFromMaps(MI);
+ MI->eraseFromParent();
+ }
}
// Delete all spilled registers.
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