Author: evancheng
Date: Tue Aug 14 18:19:28 2007
New Revision: 41084
URL: http://llvm.org/viewvc/llvm-project?rev=41084&view=rev
Log:
Fix for PR1596: AdjustCopiesBackFrom() should conservatively check if any of
its sub-registers may overlap with the interval of the copy that's being
coalesced.
Modified:
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=41084&r1=41083&r2=41084&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Tue Aug 14 18:19:28 2007
@@ -125,6 +125,19 @@
// live-range starts. If there are no intervening live ranges between them
in
// IntB, we can merge them.
if (ValLR+1 != BLR) return false;
+
+ // If a live interval is a physical register, conservatively check if any
+ // of its sub-registers is overlapping the live interval of the virtual
+ // register. If so, do not coalesce.
+ if (MRegisterInfo::isPhysicalRegister(IntB.reg) &&
+ *mri_->getSubRegisters(IntB.reg)) {
+ for (const unsigned* SR = mri_->getSubRegisters(IntB.reg); *SR; ++SR)
+ if (li_->hasInterval(*SR) && IntA.overlaps(li_->getInterval(*SR))) {
+ DOUT << "Interfere with sub-register ";
+ DEBUG(li_->getInterval(*SR).print(DOUT, mri_));
+ return false;
+ }
+ }
DOUT << "\nExtending: "; IntB.print(DOUT, mri_);
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