From 7fb5632e73329d1fdff2d3acbba8587fb8ed9f7b Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Fri, 14 Oct 2011 00:34:31 +0000 Subject: Add value numbers when spilling dead defs. When spilling around an instruction with a dead def, remember to add a value number for the def. The missing value number wouldn't normally create problems since there would be an incoming live range as well. However, due to another bug we could spill a dead V_SET0 instruction which doesn't read any values. The missing value number caused an empty live range to be created which is dangerous since it doesn't interfere with anything. This fixes part of PR11125. llvm-svn: 141923 --- llvm/lib/CodeGen/InlineSpiller.cpp | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/InlineSpiller.cpp b/llvm/lib/CodeGen/InlineSpiller.cpp index b63611b94c1..726af469657 100644 --- a/llvm/lib/CodeGen/InlineSpiller.cpp +++ b/llvm/lib/CodeGen/InlineSpiller.cpp @@ -1187,8 +1187,16 @@ void InlineSpiller::spillAroundUses(unsigned Reg) { DEBUG(dbgs() << "\trewrite: " << Idx << '\t' << *MI); // FIXME: Use a second vreg if instruction has no tied ops. - if (Writes && hasLiveDef) + if (Writes) { + if (hasLiveDef) insertSpill(NewLI, OldLI, Idx, MI); + else { + // This instruction defines a dead value. We don't need to spill it, + // but do create a live range for the dead value. + VNInfo *VNI = NewLI.getNextValue(Idx, 0, LIS.getVNInfoAllocator()); + NewLI.addRange(LiveRange(Idx, Idx.getNextSlot(), VNI)); + } + } DEBUG(dbgs() << "\tinterval: " << NewLI << '\n'); } -- cgit v1.2.3