[Bug tree-optimization/60770] disappearing clobbers

glisse at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Sat Jun 28 12:27:00 GMT 2014


--- Comment #9 from Marc Glisse <glisse at gcc dot gnu.org> ---
The warnings are "normal", they also appear in a non-patched build, so that
leaves only the coalesce errors.

(In reply to Eric Botcazou from comment #8)
> The Ada front-end is the only serious user of abnormal call edges and the
> like (for example SSA_NAME_OCCURS_IN_ABNORMAL_PHI) so this is not very
> surprising.

Indeed there are setjmp related things nearby in the dump and it is most likely
related to this error.

Though I am not sure what coalesce is unhappy about:

Unable to coalesce ssa_names 3329 and 3388 which are marked as MUST COALESCE.
r_3329(ab) and  r_3388(D)(ab)

That's likely:
  # r_3329(ab) = PHI <r_3388(D)(ab)(3), ... (super long)
  # r_3330(ab) = PHI <r_3388(D)(ab)(6), r_3329(ab)(7)>

but r_3388 only ever appears on the rhs of PHI nodes, always uninitialized, so
it can essentially be ignored. Well, I'll keep looking when I can. (tools like
delta have a hard time removing much more than the comments there, the size of
the testcase (ali.adb) doesn't help)

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