diff options
Diffstat (limited to 'lib/CodeGen/SimpleRegisterCoalescing.cpp')
| -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 9d43750f1c..67e829efee 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -264,8 +264,13 @@ bool SimpleRegisterCoalescing::JoinCopy(MachineInstr *CopyMI, if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) { DOUT << "Interfere with sub-register "; DEBUG(li_->getInterval(*SR).print(DOUT, mri_)); - return true; + return true; // Not coalescable } + } else if (li_->getInterval(repDstReg).getSize() > + li_->getInterval(repSrcReg).getSize()) { + // Be conservative. If both sides are virtual registers, do not coalesce + // if the sub-register live interval is longer. + return false; } } else if (differingRegisterClasses(repSrcReg, repDstReg)) { // If they are not of the same register class, we cannot join them. |