[Bug rtl-optimization/64081] [5/6/7 Regression] r217827 prevents RTL loop unroll

[aldyh at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64081

Aldy Hernandez <aldyh at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |aldyh at redhat dot com

--- Comment #41 from Aldy Hernandez <aldyh at redhat dot com> ---
Created attachment 40674
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40674&action=edit
miscompiled tree-ssa-structalias.ii on AIX

It looks like tree-ssa-structalias.c is being miscompiled, particularly
build_pred_graph.  If I add __attribute__((optimize("-O0"))) to
build_pred_cgraph's definition and rebuild stage2's cc1 we have a
non-segfaulting cc1.

I wonder if we can now build a cross (with attachment 40673) to
--target=powerpc-ibm-aix7.2.0.0 and use the attached tree-ssa-structalias.ii to
compare before and after dumps.