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| author | Bjorn Pettersson <bjorn.a.pettersson@ericsson.com> | 2018-08-21 07:49:05 +0000 |
|---|---|---|
| committer | Bjorn Pettersson <bjorn.a.pettersson@ericsson.com> | 2018-08-21 07:49:05 +0000 |
| commit | 880f29157770a2fe51f08887c363e789f8d47ba6 (patch) | |
| tree | 7b6a588cb789735d9680b3219bcb634ac8322a61 /llvm/test | |
| parent | f1dc867396a57afb26d91d1bd8d039817c263805 (diff) | |
| download | bcm5719-llvm-880f29157770a2fe51f08887c363e789f8d47ba6.tar.gz bcm5719-llvm-880f29157770a2fe51f08887c363e789f8d47ba6.zip | |
[RegisterCoalescer] Do not assert when trying to remat dead values
Summary:
RegisterCoalescer::reMaterializeTrivialDef used to assert that
the input register was live in. But as shown by the new
coalesce-dead-lanes.mir test case that seems to be a valid
scenario. We now return false instead of the assert, simply
avoiding to remat the dead def.
Normally a COPY of an undef value is eliminated by
eliminateUndefCopy(). Although we only do that when the
destination isn't a physical register. So the situation
above should be limited to the case when we copy an undef
value to a physical register.
Reviewers: kparzysz, wmi, tpr
Reviewed By: kparzysz
Subscribers: MatzeB, qcolombet, tpr, llvm-commits
Differential Revision: https://reviews.llvm.org/D50842
llvm-svn: 340255
Diffstat (limited to 'llvm/test')
| -rw-r--r-- | llvm/test/CodeGen/X86/coalesce-dead-lanes.mir | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/coalesce-dead-lanes.mir b/llvm/test/CodeGen/X86/coalesce-dead-lanes.mir new file mode 100644 index 00000000000..a1bd9df9e67 --- /dev/null +++ b/llvm/test/CodeGen/X86/coalesce-dead-lanes.mir @@ -0,0 +1,19 @@ +# RUN: llc -run-pass simple-register-coalescing -O0 -mtriple x86_64-pc-linux-gnu -o - %s | FileCheck %s + +--- +name: foo +tracksRegLiveness: true +body: | + bb.0: + undef %18.sub_8bit_hi:gr16_abcd = COPY undef $al + %1:gr16_abcd = COPY killed %18 + dead %8:gr8 = COPY undef %1.sub_8bit_hi + $al = COPY undef %8 +... + +# This used to hit an assertion: +# lib/CodeGen/RegisterCoalescer.cpp:1110: RegisterCoalescer::reMaterializeTrivialDef(...): Assertion `ValNo && "CopyMI input register not live"' failed. +# +# CHECK_LABEL: name: foo +# CHECK: bb.0: +# CHECK-NEXT: $al = COPY undef %2:gr8 |
