6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-11-01 00:17:01 +00:00
Code Issues Projects Releases Wiki Activity

Make sure the whole live range is covered when values are pruned twice.

Browse Source 
JoinVals::pruneValues() calls LIS->pruneValue() to avoid conflicts when
overlapping two different values. This produces a set of live range end
points that are used to reconstruct the live range (with SSA update)
after joining the two registers.

When a value is pruned twice, the set of end points was insufficient:

  v1 = DEF
  v1 = REPLACE1
  v1 = REPLACE2
  KILL v1

The end point at KILL would only reconstruct the live range from
REPLACE2 to KILL, leaving the range REPLACE1-REPLACE2 dead.

Add REPLACE2 as an end point in this case so the full live range is
reconstructed.

This fixes PR13999.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165056 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2012-10-02 21:46:39 +00:00
parent abe704309f
commit 27cb347d0e
2 changed files with 31 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
lib/CodeGen/RegisterCoalescer.cpp
View File

@@ -1733,11 +1733,15 @@ void JoinVals::pruneValues(JoinVals &Other,
// This value takes precedence over the value in Other.LI.
LIS->pruneValue(&Other.LI, Def, &EndPoints);
// Remove <def,read-undef> flags. This def is now a partial redef.
if (!Def.isBlock())
if (!Def.isBlock()) {
for (MIOperands MO(Indexes->getInstructionFromIndex(Def));
MO.isValid(); ++MO)
if (MO->isReg() && MO->isDef() && MO->getReg() == LI.reg)
MO->setIsUndef(false);
// This value will reach instructions below, but we need to make sure
// the live range also reaches the instruction at Def.
EndPoints.push_back(Def);
}
DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def
<< ": " << Other.LI << '\n');
break;