https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78211
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |marxin at gcc dot gnu.org
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This seems to be IPA-ICF bug.
With -fdump-ipa-icf-all
I'm seeing differences like:
group: with 1 classes:
- class with id: 1, hash: 3010449829, items: 2
-
_ZNK8VwViewer13FindViewPlaneERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(0x7fdb1be7b900/2)
_ZN8VwViewer13FindViewPlaneERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(0x7fdb1be7b800/1)
+ class with id: 0, hash: 1515816170, items: 2
+ _ZN11VwViewer_2D15undrawStickyBoxEv(0x7f12887d2c00/4)
_ZN11VwViewer_2D13drawStickyBoxEv(0x7f12887d2b00/3)
group: with 1 classes:
- class with id: 0, hash: 698082993, items: 2
- _ZN11VwViewer_2D15undrawStickyBoxEv(0x7fdb1be7bb00/4)
_ZN11VwViewer_2D13drawStickyBoxEv(0x7fdb1be7ba00/3)
+ class with id: 1, hash: 3232079217, items: 2
+
_ZNK8VwViewer13FindViewPlaneERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(0x7f12887d2a00/2)
_ZN8VwViewer13FindViewPlaneERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE(0x7f12887d2900/1)
Dump after WPA based types groups
Congruence classes: 2 (unique hash values: 2), with total: 4 items
Class size histogram [num of members]: number of classe number of classess
Remember the basic rules for -fcompare-debug - DECL_UID can be different, but
their order must be the same (essentially -g can create bigger gaps in between
them), SSA_NAME_VERSION must be identical, and cfun->funcdef_no must be
identical.
The last one is what breaks, IPA-ICF creates funcdef_no that are swapped.
Hashing to different hash values is fine, but care must be taken when actually
traversing the hash tables to generate stuff in the same order between -g and
-g0 if it could affect code generation in any way.
