[RFC][patch] If-conversion of COMPONENT_REFs

[Ira Rosen <ira dot rosen at linaro dot org>]

Hi,

With this patch a data-ref is marked as unconditionally read or
written also if its adjacent field is read or written unconditionally
in the loop.
My concern is that this is not safe enough, even though the fields
have to be non-pointers and non-aggregates, and this optimization is
applied only with -ftree-loop-if-convert-stores flag.

Bootstrapped on powerpc64-suse-linux and tested on x86_64-suse-linux.

OK for trunk?

Thanks,
Ira


ChangeLog:

         * tree-if-conv.c (memrefs_read_or_written_unconditionally): Return true
         if an adjacent field of the data-ref is accessed unconditionally.

testsuite/ChangeLog:

         * gcc.dg/vect/if-cvt-stores-vect-ifcvt-18.c: New test.
         * gcc.dg/vect/vect.exp: Run if-cvt-stores-vect* tests with
         -ftree-loop-if-convert-stores.

Attachment: if-cvt.txt
Description: Text document