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| author | Bjorn Pettersson <bjorn.a.pettersson@ericsson.com> | 2018-09-20 06:59:18 +0000 |
|---|---|---|
| committer | Bjorn Pettersson <bjorn.a.pettersson@ericsson.com> | 2018-09-20 06:59:18 +0000 |
| commit | b2154af25f52589360eb43e2b74413dbba461aff (patch) | |
| tree | 827d8c93d0bc3a41458a81724e2f0036e70502df /llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | |
| parent | 1f6020798493b536304dd36b393682b062ef1fbd (diff) | |
| download | llvm-b2154af25f52589360eb43e2b74413dbba461aff.zip llvm-b2154af25f52589360eb43e2b74413dbba461aff.tar.gz llvm-b2154af25f52589360eb43e2b74413dbba461aff.tar.bz2 | |
[MachineVerifier] Relax checkLivenessAtDef regarding dead subreg defs
Summary:
Consider an instruction that has multiple defs of the same
vreg, but defining different subregs:
%7.sub1:rc, dead %7.sub2:rc = inst
Calling checkLivenessAtDef for the live interval associated
with %7 incorrectly reported "live range continues after a
dead def". The live range for %7 has a dead def at the slot
index for "inst" even if the live range continues (given that
there are later uses of %7.sub1).
This patch adjusts MachineVerifier::checkLivenessAtDef
to allow dead subregister definitions, unless we are checking
a subrange (when tracking subregister liveness).
A limitation is that we do not detect the situation when the
live range continues past an instruction that defines the
full virtual register by multiple dead subreg defines.
I also removed some dead code related to physical register
in checkLivenessAtDef. Wwe only call that method for virtual
registers, so I added an assertion instead.
Reviewers: kparzysz
Reviewed By: kparzysz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52237
llvm-svn: 342618
Diffstat (limited to 'llvm/lib/Bitcode/Writer/BitcodeWriter.cpp')
0 files changed, 0 insertions, 0 deletions