https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125366
Sam James <sjames at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |sjames at gcc dot gnu.org
--- Comment #8 from Sam James <sjames at gcc dot gnu.org> ---
Ah, sorry for missing it.
It's similar to the previous issues we saw with gimple-match and insn-recog and
it looked like it might be a compare-debug problem, and I didn't manage to
reduce it.
```
$ ~/git/gcc/contrib/compare-lto -p stage2-gimple-match-5.o
stage3-gimple-match-5.o
stage2-gimple-match-5.o stage3-gimple-match-5.o differ: byte 41, line 1
stripping off LTO option section, then retrying
stage2-gimple-match-5.o.stripped. stage3-gimple-match-5.o.stripped. differ:
byte 174771, line 644
preserving stage2-gimple-match-5.o.stripped. stage3-gimple-match-5.o.stripped.
$ diffoscope stage{2,3}-gimple-match-5.o.stripped -text-color=always | less -R
--- stage2-gimple-match-5.o.stripped
+++ stage3-gimple-match-5.o.stripped
├── readelf --wide --sections {}
│ @@ -7,188 +7,188 @@
│ [ 2] .data PROGBITS 0000000000000000 000040 000000 00
WA 0 0 1
│ [ 3] .bss NOBITS 0000000000000000 000040 000000 00
WA 0 0 1
│ [ 4] .gnu.lto_.odr_types.1 PROGBITS 0000000000000000 000040 025088
00 E 0 0 1
│ [ 5] .gnu.lto_.profile.1 PROGBITS 0000000000000000 0250c8 000095 00
E 0 0 1
│ [ 6] .gnu.lto_.icf.1 PROGBITS 0000000000000000 02515d 0014c3 00
E 0 0 1
│ [ 7] .gnu.lto_.ipa_sra.1 PROGBITS 0000000000000000 026620 000e89 00
E 0 0 1
│ [ 8] .gnu.lto_.inline.1 PROGBITS 0000000000000000 0274a9 0035f1 00
E 0 0 1
│ - [ 9] .gnu.lto_.jmpfuncs.1 PROGBITS 0000000000000000 02aa9a 003edf
00 E 0 0 1
│ - [10] .gnu.lto_.pureconst.1 PROGBITS 0000000000000000 02e979 00018f
00 E 0 0 1
│ - [11] .gnu.lto_.ipa_modref.1 PROGBITS 0000000000000000 02eb08 000a85
00 E 0 0 1
│ - [12] .gnu.lto_.lto.1 PROGBITS 0000000000000000 02f58d 000008 00
E 0 0 1
[...]
│ + [ 9] .gnu.lto_.jmpfuncs.1 PROGBITS 0000000000000000 02aa9a 003ee2
00 E 0 0 1
│ + [10] .gnu.lto_.pureconst.1 PROGBITS 0000000000000000 02e97c 00018f
00 E 0 0 1
│ + [11] .gnu.lto_.ipa_modref.1 PROGBITS 0000000000000000 02eb0b 000a86
00 E 0 0 1
│ + [12] .gnu.lto_.lto.1 PROGBITS 0000000000000000 02f591 000008 00
E 0 0 1
[...]
$ objcopy -O binary --set-section-flags *=ALLOC -j .gnu.lto_.jmpfuncs.1
stage2-gimple-match-5.o.stripped jmpfuncs.stage2.z
$ objcopy -O binary --set-section-flags *=ALLOC -j .gnu.lto_.jmpfuncs.1
stage3-gimple-match-5.o.stripped jmpfuncs.stage3.z
$ diffoscope jmpfuncs.stage{2,3}
--- jmpfuncs.stage2
+++ jmpfuncs.stage3
@@ -145,22 +145,22 @@
00000900: 7f04 8101 0100 0001 0202 8f01 4001 0140 ............@..@
00000910: 017f 4001 0040 017f 0201 d601 0001 0202 ..@..@..........
00000920: af01 0140 01d0 0040 01d0 0040 01d0 0040 ...@...@...@...@
00000930: 0100 0200 0000 0400 0001 0202 8e01 0140 ...............@
00000940: 0100 4001 0140 0100 4001 0102 01bc 0100 ..@..@..@.......
00000950: 0102 028e 0101 4001 0040 0100 4001 0040 ......@..@..@..@
00000960: 0100 2102 0101 0f7f 0293 017f 0220 0400 ..!.......... ..
-00000970: 0001 0202 b401 0120 0100 2001 ffff 0320 ....... .. ....
+00000970: 0001 0202 8801 0120 0100 2001 ffff 0320 ....... .. ....
00000980: 0100 2001 ffff 0300 0001 0202 a201 0120 .. ............
00000990: 0100 2001 0120 0100 2001 0104 0000 0000 .. .. .. .......
000009a0: 0001 0202 2940 0101 4001 7f40 0100 4001 ....)@..@..@..@.
000009b0: 7804 0000 0102 028e 0101 4001 0040 0101 x.........@..@..
000009c0: 4001 0040 0101 0201 bc01 0001 0202 8e01 @..@............
000009d0: 0140 0100 4001 0040 0100 4001 0002 0000 .@..@..@..@.....
-000009e0: 0004 0000 0102 02b4 0101 2001 0020 01ff .......... .. ..
+000009e0: 0004 0000 0102 0288 0101 2001 0020 01ff .......... .. ..
[...]
```
If you take the two command lines for gimple-match-5.o with stage2 and also
stage3, and run them manually, you should still see a differing
gimple-match-5.o after compare-lto -p (you need compare-lto to strip the
options section). If you then run them again with say -g0 on both, does
compare-lto then pass?
