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Re: [PATCH] strlenopt improvements
> Can you please explain this stmt_set_p stuff? dont_invalidate should be
> only set on strinfos that will be seen by the immediately following
> maybe_invalidate call (at the end of handle_builtin_strcpy caller -
> strlen_optimize_stmt). If you set it on which unshare_strinfo is called,
> if there is no unsharing, it is obviously fine, but if there is unsharing,
> then dont_invalidate will be set on some strinfo that won't be seen by the
> next may_invalidate. It might trigger in some other basic block and might
> cause wrong code.
It's not needed. I've retested it with the following loop instead. No
regressions on s390x and x86_64. Ok to apply?
+ if (dsi->prev != 0 && (chainsi = verify_related_strinfos (dsi)) != NULL)
+ for (; chainsi && chainsi != dsi; chainsi = get_strinfo (chainsi->next))
+ /* When setting a stmt for delayed length computation
+ prevent all strinfos through dsi from being
+ invalidated. */
+ chainsi = unshare_strinfo (chainsi);
+ chainsi->stmt = stmt;
+ chainsi->length = NULL_TREE;
+ chainsi->endptr = NULL_TREE;
+ chainsi->dont_invalidate = true;