https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113059
Bug ID: 113059
Summary: [14 regression] fftw fails tests for -O3 -m32
-march=znver2 since r14-6210-ge44ed92dbbe9d4
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: jakub at gcc dot gnu.org
Target Milestone: ---
fftw started failing tests (very inconsistently - almost always fails, but
sometimes w/ segfault, sometimes with wrong results) since
r14-6210-ge44ed92dbbe9d4.
Might be a continuation of PR112572. We had pinskia's workaround patch applied
until r14-6210-ge44ed92dbbe9d4 landed so I may need to double check.
I can reproduce with the following:
```
./configure CFLAGS="-O3 -m32 -march=znver2 -ggdb3"
make -j$(nproc)
make -j$(nproc) check
```
Just `tests/bench --verbose=1 --verify //obrd896` seems to be a good crasher
for me.
```
Program received signal SIGSEGV, Segmentation fault.
r2cf_32 (R0=0xffff97c0, R1=0xffff98d0, Cr=0xffff97c0, Ci=<optimized out>,
rs=<optimized out>, csr=0x56690040, csi=0x0, v=<optimized out>, ivs=1, ovs=1)
at r2cf_32.c:490
490 Ci[WS(csi, 8)] = T29 - T28;
(gdb) bt
#0 r2cf_32 (R0=0xffff97c0, R1=0xffff98d0, Cr=0xffff97c0, Ci=<optimized out>,
rs=<optimized out>, csr=0x56690040, csi=0x0, v=<optimized out>, ivs=1, ovs=1)
at r2cf_32.c:490
#1 0x56632963 in dobatch_r2hc (ego=0x566916b0, I=0x56680e80, O=0x56680e80,
buf=0xffff97c0, batchsz=1) at direct-r2c.c:91
#2 0x56632a5d in iterate (ego=0x566916b0, I=<optimized out>, O=<optimized
out>, dobatch=0x56632880 <dobatch_r2hc>) at direct-r2c.c:142
#3 0x565a09f5 in fftw_rdft_solve (ego_=0x566916b0, p_=0x566921d0) at
solve.c:29
#4 0x565603eb in measure (iter=1, p=<optimized out>, pln=<optimized out>) at
timer.c:136
#5 fftw_measure_execution_time (plnr=0x56684690, pln=0x566916b0, p=0x566921d0)
at timer.c:159
#6 0x5655d853 in evaluate_plan (ego=ego@entry=0x56684690,
pln=pln@entry=0x566916b0, p=p@entry=0x566921d0) at planner.c:460
#7 0x5655e773 in search0 (ego=ego@entry=0x56684690, p=p@entry=0x566921d0,
slvndx=slvndx@entry=0xffffbbac, flagsp=<optimized out>) at planner.c:529
#8 0x5655eb37 in search (flagsp=0xffffbbb0, slvndx=0xffffbbac, p=0x566921d0,
ego=0x56684690) at planner.c:600
#9 mkplan (ego=<optimized out>, p=<optimized out>) at planner.c:711
[...]
```
Reducing is challenging so far, as FFTW is massive. I'm not going to waste much
more time on that, but I'll do the usual bisecting object files and such now.
