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[Bug tree-optimization/70509] wrong code with extract from a v64qi
- From: "glisse at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sun, 03 Apr 2016 04:31:35 +0000
- Subject: [Bug tree-optimization/70509] wrong code with extract from a v64qi
- Auto-submitted: auto-generated
- References: <bug-70509-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70509
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Zdenek Sojka from comment #2)
> (In reply to Zdenek Sojka from comment #0)
> > First broken dump seems to be .forwprop, where is:
>
> .forwprop4 , that is. The problem might be that simplify_bitfield_ref() does:
> tree-ssa-forwprop.c
> ...
> 1793: index = build_int_cst (TREE_TYPE (TREE_TYPE (m)), idx * size);
> ...
>
> which builds the index of type "unsigned char", which wraps around from 256
> to 0.
> Is there any reason to have index of type "TREE_TYPE (TREE_TYPE (m))" in
> that statement?
Rereading this a few years later, I have no idea why I used that type.
bitsize_int would make more sense...