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author | Jeff Law <jlaw@ventanamicro.com> | 2024-07-21 07:36:37 -0600 |
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committer | Jeff Law <jlaw@ventanamicro.com> | 2024-07-21 07:36:37 -0600 |
commit | 91e468b72dafc9dcd5dcf7915f1d0ef172264d53 (patch) | |
tree | 74c6cacb557289c1836e48eddae3e7eb1a0f7a9e /config/mh-openedition | |
parent | 80c37335bafd323668f2be059da08fd932dbb7eb (diff) | |
download | gcc-91e468b72dafc9dcd5dcf7915f1d0ef172264d53.zip gcc-91e468b72dafc9dcd5dcf7915f1d0ef172264d53.tar.gz gcc-91e468b72dafc9dcd5dcf7915f1d0ef172264d53.tar.bz2 |
[PR rtl-optimization/115877] Fix livein computation for ext-dce
So I'm not yet sure how I'm going to break everything down, but this is easy
enough to break out as 1/N of ext-dce fixes/improvements.
When handling uses in an insn, we first determine what bits are set in the
destination which is represented in DST_MASK. Then we use that to refine what
bits are live in the source operands.
In the source operand handling section we *modify* DST_MASK if the source
operand is a SUBREG (ugh!). So if the first operand is a SUBREG, then we can
incorrectly compute which bit groups are live in the second operand, especially
if it is a SUBREG as well.
This was seen when testing a larger set of patches on the rl78 port
(builtin-arith-overflow-p-7 & pr71631 execution failures), so no new test for
this bugfix.
Run through my tester (in conjunction with other ext-dce changes) on the
various cross targets. Run individually through a bootstrap and regression
test cycle on x86_64 as well.
Pushing to the trunk.
PR rtl-optimization/115877
gcc/
* ext-dce.cc (ext_dce_process_uses): Restore the value of DST_MASK
for reach operand.
Diffstat (limited to 'config/mh-openedition')
0 files changed, 0 insertions, 0 deletions