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RegisterCoalescer: Cleanup empty subranges after shrinkToUses() 

A call to removeEmptySubranges() is necessary after every operation that
potentially removes all segments from a subregister range; this case in
the register coalescer was missing.

llvm-svn: 241027
This commit is contained in:
Matthias Braun 2015-06-30 00:33:44 +00:00
parent a7ad09d0be
commit bd23647379
2 changed files with 21 additions and 0 deletions
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1
llvm/lib/CodeGen/RegisterCoalescer.cpp
View File

@ -1449,6 +1449,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
<< format("%04X", S.LaneMask) << ")\n");
LIS->shrinkToUses(S, LI.reg);
}
LI.removeEmptySubRanges();
}
if (ShrinkMainRange) {
LiveInterval &LI = LIS->getInterval(CP.getDstReg());

20
llvm/test/CodeGen/AMDGPU/subreg-coalescer-undef-use.ll Normal file
View File

@ -0,0 +1,20 @@
; RUN: llc -march=amdgcn -mcpu=SI -o /dev/null %s
; Don't crash when the use of an undefined value is only detected by the
; register coalescer because it is hidden with subregister insert/extract.
target triple="amdgcn--"
define void @foobar(float %a0, float %a1, float addrspace(1)* %out) nounwind {
entry:
%v0 = insertelement <4 x float> undef, float %a0, i32 0
br i1 undef, label %ift, label %ife
ift:
%v1 = insertelement <4 x float> undef, float %a1, i32 0
br label %ife
ife:
%val = phi <4 x float> [ %v1, %ift ], [ %v0, %entry ]
%v2 = extractelement <4 x float> %val, i32 1
store float %v2, float addrspace(1)* %out, align 4
ret void
}