diff options
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index f0b0d58..f3ffc69 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -1290,8 +1290,13 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) { } } + // If we are joining two virtual registers and the resulting register + // class is more restrictive (fewer register, smaller size). Check if it's + // worth doing the merge. if (!SrcIsPhys && !DstIsPhys && - !isWinToJoinCrossClass(LargeReg, SmallReg, Limit)) { + (isExtSubReg || DstRC->isASubClass()) && + !isWinToJoinCrossClass(LargeReg, SmallReg, + allocatableRCRegs_[NewRC].count())) { DOUT << "\tSrc/Dest are different register classes.\n"; // Allow the coalescer to try again in case either side gets coalesced to // a physical register that's compatible with the other side. e.g. |