[llvm-commits] [llvm] r47966 - in /llvm/trunk: lib/CodeGen/SimpleRegisterCoalescing.cpp lib/CodeGen/SimpleRegisterCoalescing.h test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll
Evan Cheng
evan.cheng at apple.com
Wed Mar 5 14:09:43 PST 2008
Author: evancheng
Date: Wed Mar 5 16:09:42 2008
New Revision: 47966
URL: http://llvm.org/viewvc/llvm-project?rev=47966&view=rev
Log:
Fix a coalescer bug wrt how dead copy interval is shortened.
Added:
llvm/trunk/test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll
Modified:
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=47966&r1=47965&r2=47966&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Wed Mar 5 16:09:42 2008
@@ -451,6 +451,30 @@
}
}
+/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
+/// extended by a dead copy. Mark the last use (if any) of the val# as kill
+/// as ends the live range there. If there isn't another use, then this
+/// live range is dead.
+void SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
+ MachineInstr *CopyMI) {
+ unsigned CopyIdx = li_->getInstructionIndex(CopyMI);
+ LiveInterval::iterator MLR =
+ li.FindLiveRangeContaining(li_->getDefIndex(CopyIdx));
+ unsigned RemoveStart = MLR->start;
+ unsigned RemoveEnd = MLR->end;
+ unsigned LastUseIdx;
+ MachineOperand *LastUse = lastRegisterUse(RemoveStart, CopyIdx, li.reg,
+ LastUseIdx);
+ if (LastUse) {
+ // Shorten the liveinterval to the end of last use.
+ LastUse->setIsKill();
+ RemoveStart = li_->getDefIndex(LastUseIdx);
+ }
+ li.removeRange(RemoveStart, RemoveEnd, true);
+ if (li.empty())
+ li_->removeInterval(li.reg);
+}
+
/// JoinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
/// which are the src/dst of the copy instruction CopyMI. This returns true
/// if the copy was successfully coalesced away. If it is not currently
@@ -599,23 +623,22 @@
SrcInt.FindLiveRangeContaining(li_->getUseIndex(CopyIdx));
RemoveStart = SrcStart = SrcLR->start;
RemoveEnd = SrcEnd = SrcLR->end;
- // The instruction which defines the src is only truly dead if there are
- // no intermediate uses and there isn't a use beyond the copy.
- // FIXME: find the last use, mark is kill and shorten the live range.
if (SrcEnd > li_->getDefIndex(CopyIdx)) {
+ // If there are other uses of SrcReg beyond the copy, there is nothing to do.
isDead = false;
} else {
unsigned LastUseIdx;
MachineOperand *LastUse =
lastRegisterUse(SrcStart, CopyIdx, SrcReg, LastUseIdx);
if (LastUse) {
- // Shorten the liveinterval to the end of last use.
+ // There are uses before the copy, just shorten the live range to the end
+ // of last use.
LastUse->setIsKill();
isDead = false;
isShorten = true;
RemoveStart = li_->getDefIndex(LastUseIdx);
- RemoveEnd = SrcEnd;
} else {
+ // This live range is truly dead. Remove it.
MachineInstr *SrcMI = li_->getInstructionFromIndex(SrcStart);
if (SrcMI && SrcMI->modifiesRegister(SrcReg, tri_))
// A dead def should have a single cycle interval.
@@ -1531,16 +1554,10 @@
if (tii_->isMoveInstr(*mii, srcReg, dstReg) && srcReg == dstReg) {
// remove from def list
LiveInterval &RegInt = li_->getOrCreateInterval(srcReg);
- MachineOperand *MO = mii->findRegisterDefOperand(dstReg, false);
// If def of this move instruction is dead, remove its live range from
// the dstination register's live interval.
- if (MO->isDead()) {
- unsigned MoveIdx = li_->getDefIndex(li_->getInstructionIndex(mii));
- LiveInterval::iterator MLR = RegInt.FindLiveRangeContaining(MoveIdx);
- RegInt.removeRange(MLR->start, MoveIdx+1, true);
- if (RegInt.empty())
- li_->removeInterval(srcReg);
- }
+ if (mii->registerDefIsDead(dstReg))
+ ShortenDeadCopyLiveRange(RegInt, mii);
li_->RemoveMachineInstrFromMaps(mii);
mii = mbbi->erase(mii);
++numPeep;
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h?rev=47966&r1=47965&r2=47966&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h Wed Mar 5 16:09:42 2008
@@ -201,6 +201,12 @@
/// subregister.
void UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
+ /// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
+ /// extended by a dead copy. Mark the last use (if any) of the val# as kill
+ /// as ends the live range there. If there isn't another use, then this
+ /// live range is dead.
+ void ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+
/// lastRegisterUse - Returns the last use of the specific register between
/// cycles Start and End or NULL if there are no uses.
MachineOperand *lastRegisterUse(unsigned Start, unsigned End, unsigned Reg,
Added: llvm/trunk/test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll?rev=47966&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/2008-03-05-RegScavengerAssert.ll Wed Mar 5 16:09:42 2008
@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | llc -mtriple=powerpc-apple-darwin -enable-ppc-regscavenger
+
+declare i8* @bar(i32)
+
+define void @foo(i8* %pp) nounwind {
+entry:
+ %tmp2 = tail call i8* @bar( i32 14 ) nounwind ; <i8*> [#uses=0]
+ %tmp28 = bitcast i8* %pp to void ()** ; <void ()**> [#uses=1]
+ %tmp38 = load void ()** %tmp28, align 4 ; <void ()*> [#uses=2]
+ br i1 false, label %bb34, label %bb25
+bb25: ; preds = %entry
+ %tmp30 = bitcast void ()* %tmp38 to void (i8*)* ; <void (i8*)*> [#uses=1]
+ tail call void %tmp30( i8* null ) nounwind
+ ret void
+bb34: ; preds = %entry
+ tail call void %tmp38( ) nounwind
+ ret void
+}
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