Re: [PATCH][C] Fix PR39983, more &a vs. &a[0] issues

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Sun, May 3, 2009 at 9:31 AM, Richard Guenther <rguenther@suse.de> wrote:
>
> This fixes PR39983 - a case where the gimplification time fixup of
> &a vs. &a[0] doesn't work because we do not gimplify static initializers.
>
> Thus I revisited yet another option of fixing the C frontend for real
> instead of fixing things up after-the-fact. ?The following is what
> comes out of this (and x86-64 {,-m32} testing).
>
> The fallout is in builtin folding where the builtins accept void *
> typed arguments and in the aliasing warning machinery. ?Both due
> to the fact that int a[25] now decays to (int *)&a instead of &a
> (or &a[0] after fixup) just like struct { int a[25]; } x; x.a always
> did. ?Both are latent missed optimizations / warnings anyway.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu for all C family
> languages with {,-m32}.
>
> Are the C frontend changes ok for trunk?
>
> Thanks,
> Richard.
>
> 2009-05-03 ?Richard Guenther ?<rguenther@suse.de>
>
> ? ? ? ?PR c/39983
> ? ? ? ?* c-typeck.c (array_to_pointer_conversion): Do not built
> ? ? ? ?ADDR_EXPRs of arrays of pointer-to-element type.
> ? ? ? ?* c-gimplify.c (c_gimplify_expr): Revert change fixing
> ? ? ? ?up wrong ADDR_EXPRs after-the-fact.
> ? ? ? ?* c-common.c (strict_aliasing_warning): Strip pointer
> ? ? ? ?conversions for obtaining the original type.
> ? ? ? ?* builtins.c (fold_builtin_memset): Handle array types.
> ? ? ? ?(fold_builtin_memory_op): Handle folded POINTER_PLUS_EXPRs
> ? ? ? ?and array types
>
> ? ? ? ?* gcc.c-torture/compile/pr39983.c: New testcase.

This triggered:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40015

-- 
H.J.