[Bug tree-optimization/65443] Don't peel last iteration from loop in transform_to_exit_first_loop

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65443

vries at gcc dot gnu.org changed:

           What    |Removed                     |Added
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  Attachment #35092|0                           |1
        is obsolete|                            |

--- Comment #11 from vries at gcc dot gnu.org ---
Created attachment 35103
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35103&action=edit
WIP patch

Updated patch. Skips cases that it can't handle, so it's on by default now.
Bootstrapped and reg-tested on x86_64, no issues found.