On Thu, Feb 9, 2023 at 10:57 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Thu, Feb 09, 2023 at 09:16:17AM +0100, Richard Biener via Gcc-patches
> wrote:
> > On Wed, Feb 8, 2023 at 10:15 PM Andrew Pinski via Gcc-patches
> > <gcc-patches@gcc.gnu.org> wrote:
> > >
> > > The same problem as PR 88739 has crept in but
> > > this time in match.pd when simplifying bit_field_ref of
> > > an bit_insert. That is we are generating a BIT_FIELD_REF
> > > of a non-mode-precision integral type.
> > >
> > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
> >
> > Hmm. Can we handle the case of the extraction exactly covering the
> > insertion separately then and simplify to plain @1?
>
> I was suggesting that in the PR. Here it is as an incremental patch
> on top of Andrew's patch. Ok for trunk if it passes bootstrap/regtest?
Yes.
Thanks,
Richard.
> On the newly added testcase the ifcvt-folding difference without/with the
> incremental patch is:
> --- pr108688.c.171t.ifcvt_ 2023-02-09 10:47:30.169916845 +0100
> +++ pr108688.c.171t.ifcvt 2023-02-09 10:48:44.942793453 +0100
> @@ -25,6 +25,8 @@ Number of blocks in CFG: 11
> Number of blocks to update: 5 ( 45%)
>
>
> +Applying pattern match.pd:7487, gimple-match.cc:243200
> +Applying pattern match.pd:3987, gimple-match.cc:75423
> Matching expression match.pd:1677, gimple-match.cc:209
> Applying pattern match.pd:1733, gimple-match.cc:109481
> Matching expression match.pd:2393, gimple-match.cc:852
> @@ -70,7 +72,6 @@ void foo ()
> signed char _29;
> <unnamed-signed:7> _30;
> unsigned int ivtmp_33;
> - <unnamed-signed:7> _ifc__35;
> unsigned char _ifc__37;
> unsigned char _ifc__38;
> unsigned char _ifc__39;
> @@ -91,8 +92,7 @@ void foo ()
> _2 = (<unnamed-signed:7>) a.0_1;
> _ifc__38 = u.D.2741;
> _ifc__39 = BIT_INSERT_EXPR <_ifc__38, _2, 0 (7 bits)>;
> - _ifc__35 = BIT_FIELD_REF <_ifc__39, 7, 0>;
> - _4 = (signed char) _ifc__35;
> + _4 = (signed char) _2;
> b.1_5 = b;
> _6 = (signed char) b.1_5;
> _7 = _4 ^ _6;
>
> 2023-02-09 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/108688
> * match.pd (bit_field_ref [bit_insert]): Simplify BIT_FIELD_REF
> of BIT_INSERT_EXPR extracting exactly all inserted bits even
> when without mode precision. Formatting fixes.
>
> * gcc.c-torture/compile/pr108688-1.c: Add PR number as comment.
> * gcc.dg/pr108688.c: New test.
>
> --- gcc/match.pd.jj 2023-02-09 09:42:53.782418805 +0100
> +++ gcc/match.pd 2023-02-09 10:48:06.859365613 +0100
> @@ -7475,13 +7475,16 @@ (define_operator_list SYNC_FETCH_AND_AND
> }
> (switch
> (if ((!INTEGRAL_TYPE_P (TREE_TYPE (@1))
> - || type_has_mode_precision_p (TREE_TYPE (@1)))
> - && wi::leu_p (wi::to_wide (@ipos), wi::to_wide (@rpos))
> + || type_has_mode_precision_p (TREE_TYPE (@1)))
> + && wi::leu_p (wi::to_wide (@ipos), wi::to_wide (@rpos))
> && wi::leu_p (wi::to_wide (@rpos) + wi::to_wide (@rsize),
> wi::to_wide (@ipos) + isize))
> (BIT_FIELD_REF @1 @rsize { wide_int_to_tree (bitsizetype,
> - wi::to_wide (@rpos)
> + wi::to_wide (@rpos)
> - wi::to_wide (@ipos)); }))
> + (if (wi::eq_p (wi::to_wide (@ipos), wi::to_wide (@rpos))
> + && compare_tree_int (@rsize, isize) == 0)
> + (convert @1))
> (if (wi::geu_p (wi::to_wide (@ipos),
> wi::to_wide (@rpos) + wi::to_wide (@rsize))
> || wi::geu_p (wi::to_wide (@rpos),
> --- gcc/testsuite/gcc.c-torture/compile/pr108688-1.c.jj 2023-02-09
> 09:42:53.782418805 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr108688-1.c 2023-02-09
> 10:34:18.339817796 +0100
> @@ -1,4 +1,4 @@
> -
> +/* PR tree-optimization/108688 */
>
> union U { signed int d : 7; signed int e : 2; } u;
> int a, b;
> @@ -12,4 +12,3 @@ foo (void)
> u.e ^= b;
> }
> }
> -
> --- gcc/testsuite/gcc.dg/pr108688.c.jj 2023-02-09 10:50:27.468253110 +0100
> +++ gcc/testsuite/gcc.dg/pr108688.c 2023-02-09 10:50:16.383419646 +0100
> @@ -0,0 +1,16 @@
> +/* PR tree-optimization/108688 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fno-tree-pre -fno-tree-fre -fno-tree-dominator-opts
> -fno-tree-loop-im -fno-code-hoisting" } */
> +
> +union U { signed int d : 7; signed int e : 2; } u;
> +int a, b;
> +
> +void
> +foo (void)
> +{
> + for (int i = 0; i < 64; i++)
> + {
> + u.d = a;
> + u.d ^= b;
> + }
> +}
>
>
> Jakub
>
