On Tue, 31 Mar 2020, Jakub Jelinek wrote:
> Hi!
>
> The following patch adjusts simplify_rotate to recognize more rotates,
> basically we allow even some same precision integral -> integral
> conversions, with the requirement that the RSHIFT_EXPR operand has to be
> done in unsigned type (i.e. logical right shift), so that we compensate for
> the combiner no longer being able to simplify those into rotates on some
> targets.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2020-03-31 Jakub Jelinek <ja...@redhat.com>
>
> PR rtl-optimization/94344
> * tree-ssa-forwprop.c (simplify_rotate): Handle also same precision
> conversions, either on both operands of |^+ or just one. Handle
> also extra same precision conversion on RSHIFT_EXPR first operand
> provided RSHIFT_EXPR is performed in unsigned type.
>
> * gcc.dg/pr94344.c: New test.
>
> --- gcc/tree-ssa-forwprop.c.jj 2020-03-23 19:43:00.309774530 +0100
> +++ gcc/tree-ssa-forwprop.c 2020-03-30 14:50:16.303668479 +0200
> @@ -1562,14 +1562,14 @@ simplify_rotate (gimple_stmt_iterator *g
> for (i = 0; i < 2; i++)
> defcodefor_name (arg[i], &def_code[i], &def_arg1[i], &def_arg2[i]);
>
> - /* Look through narrowing conversions. */
> + /* Look through narrowing (or same precision) conversions. */
> if (CONVERT_EXPR_CODE_P (def_code[0])
> && CONVERT_EXPR_CODE_P (def_code[1])
> && INTEGRAL_TYPE_P (TREE_TYPE (def_arg1[0]))
> && INTEGRAL_TYPE_P (TREE_TYPE (def_arg1[1]))
> && TYPE_PRECISION (TREE_TYPE (def_arg1[0]))
> == TYPE_PRECISION (TREE_TYPE (def_arg1[1]))
> - && TYPE_PRECISION (TREE_TYPE (def_arg1[0])) > TYPE_PRECISION (rtype)
> + && TYPE_PRECISION (TREE_TYPE (def_arg1[0])) >= TYPE_PRECISION (rtype)
> && has_single_use (arg[0])
> && has_single_use (arg[1]))
> {
> @@ -1579,6 +1579,21 @@ simplify_rotate (gimple_stmt_iterator *g
> defcodefor_name (arg[i], &def_code[i], &def_arg1[i], &def_arg2[i]);
> }
> }
> + else
> + {
> + /* Handle signed rotate; the RSHIFT_EXPR has to be done
> + in unsigned type but LSHIFT_EXPR could be signed. */
> + i = (def_code[0] == LSHIFT_EXPR || def_code[0] == RSHIFT_EXPR);
> + if (CONVERT_EXPR_CODE_P (def_code[i])
> + && (def_code[1 - i] == LSHIFT_EXPR || def_code[1 - i] == RSHIFT_EXPR)
> + && INTEGRAL_TYPE_P (TREE_TYPE (def_arg1[i]))
> + && TYPE_PRECISION (rtype) == TYPE_PRECISION (TREE_TYPE (def_arg1[i]))
> + && has_single_use (arg[i]))
> + {
> + arg[i] = def_arg1[i];
> + defcodefor_name (arg[i], &def_code[i], &def_arg1[i], &def_arg2[i]);
> + }
> + }
>
> /* One operand has to be LSHIFT_EXPR and one RSHIFT_EXPR. */
> for (i = 0; i < 2; i++)
> @@ -1608,8 +1623,33 @@ simplify_rotate (gimple_stmt_iterator *g
> if (!operand_equal_for_phi_arg_p (def_arg1[0], def_arg1[1])
> || !types_compatible_p (TREE_TYPE (def_arg1[0]),
> TREE_TYPE (def_arg1[1])))
> - return false;
> - if (!TYPE_UNSIGNED (TREE_TYPE (def_arg1[0])))
> + {
> + if ((TYPE_PRECISION (TREE_TYPE (def_arg1[0]))
> + != TYPE_PRECISION (TREE_TYPE (def_arg1[1])))
> + || (TYPE_UNSIGNED (TREE_TYPE (def_arg1[0]))
> + == TYPE_UNSIGNED (TREE_TYPE (def_arg1[1]))))
> + return false;
> +
> + /* Handle signed rotate; the RSHIFT_EXPR has to be done
> + in unsigned type but LSHIFT_EXPR could be signed. */
> + i = def_code[0] != RSHIFT_EXPR;
> + if (!TYPE_UNSIGNED (TREE_TYPE (def_arg1[i])))
> + return false;
> +
> + tree tem;
> + enum tree_code code;
> + defcodefor_name (def_arg1[i], &code, &tem, NULL);
> + if (!CONVERT_EXPR_CODE_P (code)
> + || !INTEGRAL_TYPE_P (TREE_TYPE (tem))
> + || TYPE_PRECISION (TREE_TYPE (tem)) != TYPE_PRECISION (rtype))
> + return false;
> + def_arg1[i] = tem;
> + if (!operand_equal_for_phi_arg_p (def_arg1[0], def_arg1[1])
> + || !types_compatible_p (TREE_TYPE (def_arg1[0]),
> + TREE_TYPE (def_arg1[1])))
> + return false;
> + }
> + else if (!TYPE_UNSIGNED (TREE_TYPE (def_arg1[0])))
> return false;
>
> /* CNT1 + CNT2 == B case above. */
> --- gcc/testsuite/gcc.dg/pr94344.c.jj 2020-03-30 14:49:53.005016600 +0200
> +++ gcc/testsuite/gcc.dg/pr94344.c 2020-03-30 14:47:41.495981569 +0200
> @@ -0,0 +1,53 @@
> +/* PR rtl-optimization/94344 */
> +/* { dg-do compile { target { ilp32 || lp64 } } } */
> +/* { dg-options "-O2 -fdump-tree-forwprop1" } */
> +/* { dg-final { scan-tree-dump-times " r>> 27;" 4 "forwprop1" } } */
> +/* { dg-final { scan-tree-dump-times " r>> 59;" 4 "forwprop1" } } */
> +
> +int
> +f1 (int x)
> +{
> + return (x << 5) | (int)((unsigned int)x >> 27);
> +}
> +
> +unsigned int
> +f2 (int x)
> +{
> + return (x << 5) | ((unsigned int)x >> 27);
> +}
> +
> +long long int
> +f3 (long long int x)
> +{
> + return (x << 5) | (long long int)((unsigned long long int)x >> 59);
> +}
> +
> +unsigned long long int
> +f4 (long long int x)
> +{
> + return (x << 5) | ((unsigned long long int)x >> 59);
> +}
> +
> +int
> +f5 (int x)
> +{
> + return (int)((unsigned int)x >> 27) | (x << 5);
> +}
> +
> +unsigned int
> +f6 (int x)
> +{
> + return ((unsigned int)x >> 27) | (x << 5);
> +}
> +
> +long long int
> +f7 (long long int x)
> +{
> + return (long long int)((unsigned long long int)x >> 59) | (x << 5);
> +}
> +
> +unsigned long long int
> +f8 (long long int x)
> +{
> + return ((unsigned long long int)x >> 59) | (x << 5);
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
