Ping.
> -----Original Message-----
> From: Tamar Christina <tamar.christ...@arm.com>
> Sent: Wednesday, July 26, 2023 8:35 PM
> To: Tamar Christina <tamar.christ...@arm.com>; gcc-patches@gcc.gnu.org
> Cc: nd <n...@arm.com>; jos...@codesourcery.com
> Subject: RE: [PATCH 2/2][frontend]: Add novector C pragma
>
> Hi, This is a respin of the patch taking in the feedback received from the C++
> part.
>
> Simultaneously it's also a ping 😊
>
> ----
>
> Hi All,
>
> FORTRAN currently has a pragma NOVECTOR for indicating that vectorization
> should not be applied to a particular loop.
>
> ICC/ICX also has such a pragma for C and C++ called #pragma novector.
>
> As part of this patch series I need a way to easily turn off vectorization of
> particular loops, particularly for testsuite reasons.
>
> This patch proposes a #pragma GCC novector that does the same for C as
> gfortan does for FORTRAN and what ICX/ICX does for C.
>
> I added only some basic tests here, but the next patch in the series uses
> this in
> the testsuite in about ~800 tests.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
>
> Ok for master?
>
> Thanks,
> Tamar
>
> gcc/c-family/ChangeLog:
>
> * c-pragma.h (enum pragma_kind): Add PRAGMA_NOVECTOR.
> * c-pragma.cc (init_pragma): Use it.
>
> gcc/c/ChangeLog:
>
> * c-parser.cc (c_parser_while_statement, c_parser_do_statement,
> c_parser_for_statement, c_parser_statement_after_labels,
> c_parse_pragma_novector, c_parser_pragma): Wire through novector
> and
> default to false.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/vect/vect-novector-pragma.c: New test.
>
> --- inline copy of patch ---
>
> diff --git a/gcc/c-family/c-pragma.h b/gcc/c-family/c-pragma.h index
> 9cc95ab3ee376628dbef2485b84e6008210fa8fc..99cf2e8bd1c05537c1984
> 70f1aaa0a5a9da4e576 100644
> --- a/gcc/c-family/c-pragma.h
> +++ b/gcc/c-family/c-pragma.h
> @@ -87,6 +87,7 @@ enum pragma_kind {
> PRAGMA_GCC_PCH_PREPROCESS,
> PRAGMA_IVDEP,
> PRAGMA_UNROLL,
> + PRAGMA_NOVECTOR,
>
> PRAGMA_FIRST_EXTERNAL
> };
> diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc index
> 0d2b333cebbed32423d5dc6fd2a3ac0ce0bf8b94..848a850b8e123ff1c6ae1e
> c4b7f8ccbd599b1a88 100644
> --- a/gcc/c-family/c-pragma.cc
> +++ b/gcc/c-family/c-pragma.cc
> @@ -1862,6 +1862,10 @@ init_pragma (void)
> cpp_register_deferred_pragma (parse_in, "GCC", "unroll",
> PRAGMA_UNROLL,
> false, false);
>
> + if (!flag_preprocess_only)
> + cpp_register_deferred_pragma (parse_in, "GCC", "novector",
> PRAGMA_NOVECTOR,
> + false, false);
> +
> #ifdef HANDLE_PRAGMA_PACK_WITH_EXPANSION
> c_register_pragma_with_expansion (0, "pack", handle_pragma_pack); #else
> diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc index
> 24a6eb6e4596f32c477e3f1c3f98b9792f7bc92c..74f3cbb0d61b5f4c0eb300
> 672f495dde3f1517f7 100644
> --- a/gcc/c/c-parser.cc
> +++ b/gcc/c/c-parser.cc
> @@ -1572,9 +1572,11 @@ static tree c_parser_c99_block_statement
> (c_parser *, bool *,
> location_t * = NULL);
> static void c_parser_if_statement (c_parser *, bool *, vec<tree> *); static
> void
> c_parser_switch_statement (c_parser *, bool *); -static void
> c_parser_while_statement (c_parser *, bool, unsigned short, bool *); -static
> void c_parser_do_statement (c_parser *, bool, unsigned short); -static void
> c_parser_for_statement (c_parser *, bool, unsigned short, bool *);
> +static void c_parser_while_statement (c_parser *, bool, unsigned short, bool,
> + bool *);
> +static void c_parser_do_statement (c_parser *, bool, unsigned short,
> +bool); static void c_parser_for_statement (c_parser *, bool, unsigned short,
> bool,
> + bool *);
> static tree c_parser_asm_statement (c_parser *); static tree
> c_parser_asm_operands (c_parser *); static tree
> c_parser_asm_goto_operands (c_parser *); @@ -6644,13 +6646,13 @@
> c_parser_statement_after_labels (c_parser *parser, bool *if_p,
> c_parser_switch_statement (parser, if_p);
> break;
> case RID_WHILE:
> - c_parser_while_statement (parser, false, 0, if_p);
> + c_parser_while_statement (parser, false, 0, false, if_p);
> break;
> case RID_DO:
> - c_parser_do_statement (parser, false, 0);
> + c_parser_do_statement (parser, false, 0, false);
> break;
> case RID_FOR:
> - c_parser_for_statement (parser, false, 0, if_p);
> + c_parser_for_statement (parser, false, 0, false, if_p);
> break;
> case RID_GOTO:
> c_parser_consume_token (parser);
> @@ -7146,7 +7148,7 @@ c_parser_switch_statement (c_parser *parser, bool
> *if_p)
>
> static void
> c_parser_while_statement (c_parser *parser, bool ivdep, unsigned short
> unroll,
> - bool *if_p)
> + bool novector, bool *if_p)
> {
> tree block, cond, body;
> unsigned char save_in_statement;
> @@ -7168,6 +7170,11 @@ c_parser_while_statement (c_parser *parser,
> bool ivdep, unsigned short unroll,
> build_int_cst (integer_type_node,
> annot_expr_unroll_kind),
> build_int_cst (integer_type_node, unroll));
> + if (novector && cond != error_mark_node)
> + cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
> + build_int_cst (integer_type_node,
> + annot_expr_no_vector_kind),
> + integer_zero_node);
> save_in_statement = in_statement;
> in_statement = IN_ITERATION_STMT;
>
> @@ -7199,7 +7206,8 @@ c_parser_while_statement (c_parser *parser, bool
> ivdep, unsigned short unroll, */
>
> static void
> -c_parser_do_statement (c_parser *parser, bool ivdep, unsigned short unroll)
> +c_parser_do_statement (c_parser *parser, bool ivdep, unsigned short unroll,
> + bool novector)
> {
> tree block, cond, body;
> unsigned char save_in_statement;
> @@ -7228,6 +7236,11 @@ c_parser_do_statement (c_parser *parser, bool
> ivdep, unsigned short unroll)
> build_int_cst (integer_type_node,
> annot_expr_unroll_kind),
> build_int_cst (integer_type_node, unroll));
> + if (novector && cond != error_mark_node)
> + cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
> + build_int_cst (integer_type_node,
> + annot_expr_no_vector_kind),
> + integer_zero_node);
> if (!c_parser_require (parser, CPP_SEMICOLON, "expected %<;%>"))
> c_parser_skip_to_end_of_block_or_statement (parser);
>
> @@ -7296,7 +7309,7 @@ c_parser_do_statement (c_parser *parser, bool
> ivdep, unsigned short unroll)
>
> static void
> c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll,
> - bool *if_p)
> + bool novector, bool *if_p)
> {
> tree block, cond, incr, body;
> unsigned char save_in_statement;
> @@ -7452,6 +7465,11 @@ c_parser_for_statement (c_parser *parser, bool
> ivdep, unsigned short unroll,
> build_int_cst (integer_type_node,
> annot_expr_unroll_kind),
> build_int_cst (integer_type_node, unroll));
> + if (novector && cond != error_mark_node)
> + cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
> + build_int_cst (integer_type_node,
> + annot_expr_no_vector_kind),
> + integer_zero_node);
> }
> /* Parse the increment expression (the third expression in a
> for-statement). In the case of a foreach-statement, this is @@ -
> 13037,6 +13055,16 @@ c_parse_pragma_ivdep (c_parser *parser)
> return true;
> }
>
> +/* Parse a pragma GCC novector. */
> +
> +static bool
> +c_parse_pragma_novector (c_parser *parser) {
> + c_parser_consume_pragma (parser);
> + c_parser_skip_to_pragma_eol (parser);
> + return true;
> +}
> +
> /* Parse a pragma GCC unroll. */
>
> static unsigned short
> @@ -13261,38 +13289,51 @@ c_parser_pragma (c_parser *parser, enum
> pragma_context context, bool *if_p)
> case PRAGMA_OMP_ORDERED:
> return c_parser_omp_ordered (parser, context, if_p);
>
> + case PRAGMA_NOVECTOR:
> + case PRAGMA_UNROLL:
> case PRAGMA_IVDEP:
> {
> - const bool ivdep = c_parse_pragma_ivdep (parser);
> - unsigned short unroll;
> - if (c_parser_peek_token (parser)->pragma_kind ==
> PRAGMA_UNROLL)
> - unroll = c_parser_pragma_unroll (parser);
> - else
> - unroll = 0;
> - if (!c_parser_next_token_is_keyword (parser, RID_FOR)
> - && !c_parser_next_token_is_keyword (parser, RID_WHILE)
> - && !c_parser_next_token_is_keyword (parser, RID_DO))
> + bool novector = false;
> + unsigned short unroll = 0;
> + bool ivdep = false;
> +
> + switch (id)
> {
> - c_parser_error (parser, "for, while or do statement expected");
> - return false;
> + case PRAGMA_NOVECTOR:
> + novector = c_parse_pragma_novector (parser);
> + break;
> + case PRAGMA_UNROLL:
> + unroll = c_parser_pragma_unroll (parser);
> + break;
> + case PRAGMA_IVDEP:
> + ivdep = c_parse_pragma_ivdep (parser);
> + break;
> + default:
> + gcc_unreachable ();
> }
> - if (c_parser_next_token_is_keyword (parser, RID_FOR))
> - c_parser_for_statement (parser, ivdep, unroll, if_p);
> - else if (c_parser_next_token_is_keyword (parser, RID_WHILE))
> - c_parser_while_statement (parser, ivdep, unroll, if_p);
> - else
> - c_parser_do_statement (parser, ivdep, unroll);
> - }
> - return true;
>
> - case PRAGMA_UNROLL:
> - {
> - unsigned short unroll = c_parser_pragma_unroll (parser);
> - bool ivdep;
> - if (c_parser_peek_token (parser)->pragma_kind == PRAGMA_IVDEP)
> - ivdep = c_parse_pragma_ivdep (parser);
> - else
> - ivdep = false;
> + c_token *tok = c_parser_peek_token (parser);
> + bool has_more = tok->type == CPP_PRAGMA;
> + while (has_more)
> + {
> + switch (tok->pragma_kind)
> + {
> + case PRAGMA_IVDEP:
> + ivdep = c_parse_pragma_ivdep (parser);
> + break;
> + case PRAGMA_UNROLL:
> + unroll = c_parser_pragma_unroll (parser);
> + break;
> + case PRAGMA_NOVECTOR:
> + novector = c_parse_pragma_novector (parser);
> + break;
> + default:
> + has_more = false;
> + break;
> + }
> + tok = c_parser_peek_token (parser);
> + has_more = has_more && tok->type == CPP_PRAGMA;
> + }
> if (!c_parser_next_token_is_keyword (parser, RID_FOR)
> && !c_parser_next_token_is_keyword (parser, RID_WHILE)
> && !c_parser_next_token_is_keyword (parser, RID_DO)) @@ -
> 13301,11 +13342,11 @@ c_parser_pragma (c_parser *parser, enum
> pragma_context context, bool *if_p)
> return false;
> }
> if (c_parser_next_token_is_keyword (parser, RID_FOR))
> - c_parser_for_statement (parser, ivdep, unroll, if_p);
> + c_parser_for_statement (parser, ivdep, unroll, novector, if_p);
> else if (c_parser_next_token_is_keyword (parser, RID_WHILE))
> - c_parser_while_statement (parser, ivdep, unroll, if_p);
> + c_parser_while_statement (parser, ivdep, unroll, novector, if_p);
> else
> - c_parser_do_statement (parser, ivdep, unroll);
> + c_parser_do_statement (parser, ivdep, unroll, novector);
> }
> return true;
>
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-novector-pragma.c
> b/gcc/testsuite/gcc.dg/vect/vect-novector-pragma.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..3c0b8f5d2acbd27628
> 0785e8d0cbe1f7cd650266
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-novector-pragma.c
> @@ -0,0 +1,61 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target vect_int } */
> +
> +void f1 (int * restrict a, int * restrict b, int n) { #pragma GCC
> +novector
> + for (int i = 0; i < (n & -8); i++)
> + a[i] += b[i];
> +}
> +
> +void f2 (int * restrict a, int * restrict b, int n) { #pragma GCC
> +novector #pragma GCC ivdep #pragma GCC unroll 2
> + for (int i = 0; i < (n & -8); i++)
> + a[i] += b[i];
> +}
> +
> +void f3 (int * restrict a, int * restrict b, int n) { #pragma GCC ivdep
> +#pragma GCC novector #pragma GCC unroll 2
> + for (int i = 0; i < (n & -8); i++)
> + a[i] += b[i];
> +}
> +
> +void f4 (int * restrict a, int * restrict b, int n) { #pragma GCC ivdep
> +#pragma GCC unroll 2 #pragma GCC novector
> + for (int i = 0; i < (n & -8); i++)
> + a[i] += b[i];
> +}
> +
> +void f5 (int * restrict a, int * restrict b, int n) {
> + int i = 0;
> +#pragma GCC novector
> + do
> + {
> + a[i] += b[i];
> + i++;
> + }
> + while (i < (n & -8));
> +}
> +
> +void f6 (int * restrict a, int * restrict b, int n) {
> + int i = 0;
> +#pragma GCC novector
> + while (i < (n & -8))
> + {
> + a[i] += b[i];
> + i++;
> + }
> +}
> +
> +/* { dg-final { scan-tree-dump-not "LOOP VECTORIZED" "vect" } } */
