diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/RegisterCoalescer.cpp | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index 7a0c36ee347..200ad137aea 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -1912,8 +1912,14 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) { return CR_Replace; // Check for simple erasable conflicts. - if (DefMI->isImplicitDef()) + if (DefMI->isImplicitDef()) { + // We need the def for the subregister if there is nothing else live at the + // subrange at this point. + if (TrackSubRegLiveness + && (V.WriteLanes & (OtherV.ValidLanes | OtherV.WriteLanes)) == 0) + return CR_Replace; return CR_Erase; + } // Include the non-conflict where DefMI is a coalescable copy that kills // OtherVNI. We still want the copy erased and value numbers merged. |
