From 44d17ca02e0b112b4777ba6416b87793c045d8de Mon Sep 17 00:00:00 2001 From: Stanislav Mekhanoshin Date: Tue, 21 May 2019 19:32:41 +0000 Subject: Fix register coalescer failure to prune value Register coalescer fails for the test in the patch with the assertion in JoinVals::ConflictResolution `DefMI != nullptr'. It attempts to join live intervals for two adjacent instructions and erase the copy: %2:vreg_256 = COPY %1 %3:vreg_256 = COPY killed %1 The LI needs to be adjusted to kill subrange for the erased instruction and extend the subrange of the original def. That was done for the main interval only but not for the subrange. As a result subrange had a VNI pointing to the erased slot resulting in the above failure. Differential Revision: https://reviews.llvm.org/D62162 llvm-svn: 361293 --- llvm/lib/CodeGen/RegisterCoalescer.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index ca53fe4f393..58e29d613f0 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -3032,7 +3032,9 @@ void JoinVals::pruneSubRegValues(LiveInterval &LI, LaneBitmask &ShrinkMask) { // If a subrange starts at the copy then an undefined value has been // copied and we must remove that subrange value as well. VNInfo *ValueOut = Q.valueOutOrDead(); - if (ValueOut != nullptr && Q.valueIn() == nullptr) { + if (ValueOut != nullptr && (Q.valueIn() == nullptr || + (V.Identical && V.Resolution == CR_Erase && + ValueOut->def == Def))) { LLVM_DEBUG(dbgs() << "\t\tPrune sublane " << PrintLaneMask(S.LaneMask) << " at " << Def << "\n"); SmallVector EndPoints; @@ -3041,7 +3043,7 @@ void JoinVals::pruneSubRegValues(LiveInterval &LI, LaneBitmask &ShrinkMask) { // Mark value number as unused. ValueOut->markUnused(); - if (V.Identical && S.Query(OtherDef).valueOut()) { + if (V.Identical && S.Query(OtherDef).valueOutOrDead()) { // If V is identical to V.OtherVNI (and S was live at OtherDef), // then we can't simply prune V from S. V needs to be replaced // with V.OtherVNI. -- cgit v1.2.3