[Bug tree-optimization/103899] [12 Regression] make profiledbootstrap fails due to uninitialized warning in expr.c

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103899

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:db33b1059bcee3eeb36d174d59abf19f2bef5d66

commit r12-6280-gdb33b1059bcee3eeb36d174d59abf19f2bef5d66
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jan 6 15:32:57 2022 +0100

    expr: Workaround profiledbootstrap uninit false positive [PR103899]

    The threader changes resulted in a false positive warning during
    profiledbootstrap:
    In file included from ../../gcc/expr.c:26:
    ../../gcc/tree.h: In function ârtx_def* expand_expr_real_1(tree, rtx,
machine_mode, expand_modifier, rtx_def**, bool)â:
    ../../gcc/tree.h:244:56: error: âcontextâ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
      244 | #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
          |                                                        ^~~~
    ../../gcc/expr.c:10343:8: note: âcontextâ was declared here
    10343 |   tree context;
          |        ^~~~~~~
    While it will be nice to improve the uninit pass to handle it if possible
    (I do not want to close the PR until that is done), doing profiledbootstrap
    is a common thing to do, so a workaround is handy, especially as in this
    case when the workaround seems to be the right thing to do, as it moves
    a variable declaration to the only place where it is set and used and
avoids
    the weird and for uninit asking
      tree context;
    ...
      if (exp)
        context = ...;
      gcc_assert (!exp
                  || use (context)
                  || use_some_more (context));

    2022-01-06  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/103899
            * expr.c (expand_expr_real_1): Add a workaround for bogus uninit
            warning by moving context variable to the only spot where it is
used
            and moving gcc_assert into if body.