This patch fixes the current two FAILs of pr65105-5.c on x86 when
compiled with -m32.  These (temporary) breakages were fallout from my
patches to improve/upgrade (scalar) double word comparisons.
On mainline, the i386 backend currently represents a critical comparison
using (compare (and (not reg1) reg2) (const_int 0)) which isn't/wasn't
recognized by the STV pass' convertible_comparison_p.  This simple STV
patch adds support for this pattern (*testdi_not_doubleword) and
generates the vector pandn and ptest instructions expected in the
existing (failing) test case.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, where with --target_board=unix{-m32} there are two
fewer failures, and without, there are no new failures.
Ok for mainline?


2022-07-07  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
        * config/i386/i386-features.cc (convert_compare): Add support
        for *testdi_not_doubleword pattern (i.e. "(compare (and (not ...")
        by generating a pandn followed by ptest.
        (convertible_comparison_p): Recognize both *cmpdi_doubleword and
        recent *testdi_not_doubleword comparison patterns.


Thanks in advance,
Roger
--