On Tue, Oct 4, 2016 at 7:20 PM, Wilco Dijkstra <wilco.dijks...@arm.com> wrote:
> As suggested in https://gcc.gnu.org/ml/gcc-patches/2016-09/msg02216.html,
> move all existing strchr and strrchr folding from builtins.c to gimple-fold.c.
>
> Passes C/C++ regression & bootstrap.
Ok.
Thanks,
Richard.
> 2016-10-04 Wilco Dijkstra <wdijk...@arm.com>
>
> * builtins.c (fold_builtin_strchr): Remove function.
> (fold_builtin_strrchr): Likewise.
> (fold_builtin2): Remove strchr, index, strrchr, rindex cases.
> * gimple-fold.c (target_char_cst_p): New function.
> (gimple_fold_builtin_strchr) Add more foldings.
> (gimple_fold_builtin): Add index, strrchr, rindex cases.
>
> --
>
> diff --git a/gcc/builtins.c b/gcc/builtins.c
> index
> 04dcf95acd21bf092c730d5fdd08b58c497c1ab5..6f034ad78fa157bbce65e954fd754347032ab20e
> 100644
> --- a/gcc/builtins.c
> +++ b/gcc/builtins.c
> @@ -148,7 +148,6 @@ static tree rewrite_call_expr (location_t, tree, int,
> tree, int, ...);
> static bool validate_arg (const_tree, enum tree_code code);
> static rtx expand_builtin_fabs (tree, rtx, rtx);
> static rtx expand_builtin_signbit (tree, rtx);
> -static tree fold_builtin_strchr (location_t, tree, tree, tree);
> static tree fold_builtin_memchr (location_t, tree, tree, tree, tree);
> static tree fold_builtin_memcmp (location_t, tree, tree, tree);
> static tree fold_builtin_strcmp (location_t, tree, tree);
> @@ -168,7 +167,6 @@ static tree fold_builtin_varargs (location_t, tree,
> tree*, int);
>
> static tree fold_builtin_strpbrk (location_t, tree, tree, tree);
> static tree fold_builtin_strstr (location_t, tree, tree, tree);
> -static tree fold_builtin_strrchr (location_t, tree, tree, tree);
> static tree fold_builtin_strspn (location_t, tree, tree);
> static tree fold_builtin_strcspn (location_t, tree, tree);
>
> @@ -8393,14 +8391,6 @@ fold_builtin_2 (location_t loc, tree fndecl, tree
> arg0, tree arg1)
> case BUILT_IN_STRCSPN:
> return fold_builtin_strcspn (loc, arg0, arg1);
>
> - case BUILT_IN_STRCHR:
> - case BUILT_IN_INDEX:
> - return fold_builtin_strchr (loc, arg0, arg1, type);
> -
> - case BUILT_IN_STRRCHR:
> - case BUILT_IN_RINDEX:
> - return fold_builtin_strrchr (loc, arg0, arg1, type);
> -
> case BUILT_IN_STRCMP:
> return fold_builtin_strcmp (loc, arg0, arg1);
>
> @@ -8893,124 +8883,6 @@ fold_builtin_strstr (location_t loc, tree s1, tree
> s2, tree type)
> }
> }
>
> -/* Simplify a call to the strchr builtin. S1 and S2 are the arguments to
> - the call, and TYPE is its return type.
> -
> - Return NULL_TREE if no simplification was possible, otherwise return the
> - simplified form of the call as a tree.
> -
> - The simplified form may be a constant or other expression which
> - computes the same value, but in a more efficient manner (including
> - calls to other builtin functions).
> -
> - The call may contain arguments which need to be evaluated, but
> - which are not useful to determine the result of the call. In
> - this case we return a chain of COMPOUND_EXPRs. The LHS of each
> - COMPOUND_EXPR will be an argument which must be evaluated.
> - COMPOUND_EXPRs are chained through their RHS. The RHS of the last
> - COMPOUND_EXPR in the chain will contain the tree for the simplified
> - form of the builtin function call. */
> -
> -static tree
> -fold_builtin_strchr (location_t loc, tree s1, tree s2, tree type)
> -{
> - if (!validate_arg (s1, POINTER_TYPE)
> - || !validate_arg (s2, INTEGER_TYPE))
> - return NULL_TREE;
> - else
> - {
> - const char *p1;
> -
> - if (TREE_CODE (s2) != INTEGER_CST)
> - return NULL_TREE;
> -
> - p1 = c_getstr (s1);
> - if (p1 != NULL)
> - {
> - char c;
> - const char *r;
> - tree tem;
> -
> - if (target_char_cast (s2, &c))
> - return NULL_TREE;
> -
> - r = strchr (p1, c);
> -
> - if (r == NULL)
> - return build_int_cst (TREE_TYPE (s1), 0);
> -
> - /* Return an offset into the constant string argument. */
> - tem = fold_build_pointer_plus_hwi_loc (loc, s1, r - p1);
> - return fold_convert_loc (loc, type, tem);
> - }
> - return NULL_TREE;
> - }
> -}
> -
> -/* Simplify a call to the strrchr builtin. S1 and S2 are the arguments to
> - the call, and TYPE is its return type.
> -
> - Return NULL_TREE if no simplification was possible, otherwise return the
> - simplified form of the call as a tree.
> -
> - The simplified form may be a constant or other expression which
> - computes the same value, but in a more efficient manner (including
> - calls to other builtin functions).
> -
> - The call may contain arguments which need to be evaluated, but
> - which are not useful to determine the result of the call. In
> - this case we return a chain of COMPOUND_EXPRs. The LHS of each
> - COMPOUND_EXPR will be an argument which must be evaluated.
> - COMPOUND_EXPRs are chained through their RHS. The RHS of the last
> - COMPOUND_EXPR in the chain will contain the tree for the simplified
> - form of the builtin function call. */
> -
> -static tree
> -fold_builtin_strrchr (location_t loc, tree s1, tree s2, tree type)
> -{
> - if (!validate_arg (s1, POINTER_TYPE)
> - || !validate_arg (s2, INTEGER_TYPE))
> - return NULL_TREE;
> - else
> - {
> - tree fn;
> - const char *p1;
> -
> - if (TREE_CODE (s2) != INTEGER_CST)
> - return NULL_TREE;
> -
> - p1 = c_getstr (s1);
> - if (p1 != NULL)
> - {
> - char c;
> - const char *r;
> - tree tem;
> -
> - if (target_char_cast (s2, &c))
> - return NULL_TREE;
> -
> - r = strrchr (p1, c);
> -
> - if (r == NULL)
> - return build_int_cst (TREE_TYPE (s1), 0);
> -
> - /* Return an offset into the constant string argument. */
> - tem = fold_build_pointer_plus_hwi_loc (loc, s1, r - p1);
> - return fold_convert_loc (loc, type, tem);
> - }
> -
> - if (! integer_zerop (s2))
> - return NULL_TREE;
> -
> - fn = builtin_decl_implicit (BUILT_IN_STRCHR);
> - if (!fn)
> - return NULL_TREE;
> -
> - /* Transform strrchr(s1, '\0') to strchr(s1, '\0'). */
> - return build_call_expr_loc (loc, fn, 2, s1, s2);
> - }
> -}
> -
> /* Simplify a call to the strpbrk builtin. S1 and S2 are the arguments
> to the call, and TYPE is its return type.
>
> diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
> index
> 1aae8456bc81c0291ebcf136ad5c70fde2e711a5..8f74c93b086dae8608f334da2a3ec76f247c43dc
> 100644
> --- a/gcc/gimple-fold.c
> +++ b/gcc/gimple-fold.c
> @@ -57,6 +57,20 @@ along with GCC; see the file COPYING3. If not see
> #include "tree-cfg.h"
>
>
> +/* Return true if T is a constant and the value cast to a target char
> + can be represented by a host char.
> + Store the casted char constant in *P if so. */
> +
> +static bool
> +target_char_cst_p (tree t, char *p)
> +{
> + if (!tree_fits_uhwi_p (t) || CHAR_TYPE_SIZE != HOST_BITS_PER_CHAR)
> + return false;
> +
> + *p = (char)tree_to_uhwi (t);
> + return true;
> +}
> +
> /* Return true when DECL can be referenced from current unit.
> FROM_DECL (if non-null) specify constructor of variable DECL was taken
> from.
> We can get declarations that are not possible to reference for various
> @@ -1457,23 +1471,61 @@ gimple_fold_builtin_strncpy (gimple_stmt_iterator
> *gsi,
> return true;
> }
>
> -/* Simplify strchr (str, 0) into str + strlen (str).
> +/* Fold function call to builtin strchr or strrchr.
> + If both arguments are constant, evaluate and fold the result,
> + otherwise simplify str(r)chr (str, 0) into str + strlen (str).
> In general strlen is significantly faster than strchr
> due to being a simpler operation. */
> static bool
> -gimple_fold_builtin_strchr (gimple_stmt_iterator *gsi)
> +gimple_fold_builtin_strchr (gimple_stmt_iterator *gsi, bool is_strrchr)
> {
> gimple *stmt = gsi_stmt (*gsi);
> tree str = gimple_call_arg (stmt, 0);
> tree c = gimple_call_arg (stmt, 1);
> location_t loc = gimple_location (stmt);
> + const char *p;
> + char ch;
>
> - if (optimize_function_for_size_p (cfun))
> + if (!gimple_call_lhs (stmt))
> return false;
>
> - if (!integer_zerop (c) || !gimple_call_lhs (stmt))
> + if ((p = c_getstr (str)) && target_char_cst_p (c, &ch))
> + {
> + const char *p1 = is_strrchr ? strrchr (p, ch) : strchr (p, ch);
> +
> + if (p1 == NULL)
> + {
> + replace_call_with_value (gsi, integer_zero_node);
> + return true;
> + }
> +
> + tree len = build_int_cst (size_type_node, p1 - p);
> + gimple_seq stmts = NULL;
> + gimple *new_stmt = gimple_build_assign (gimple_call_lhs (stmt),
> + POINTER_PLUS_EXPR, str, len);
> + gimple_seq_add_stmt_without_update (&stmts, new_stmt);
> + gsi_replace_with_seq_vops (gsi, stmts);
> + return true;
> + }
> +
> + if (!integer_zerop (c))
> return false;
>
> + /* Transform strrchr (str, 0) to strchr (s, 0) when optimizing for size.
> */
> + if (optimize_function_for_size_p (cfun))
> + {
> + tree strchr_fn = builtin_decl_implicit (BUILT_IN_STRCHR);
> +
> + if (is_strrchr && strchr_fn)
> + {
> + gimple *repl = gimple_build_call (strchr_fn, 2, str, c);
> + replace_call_with_call_and_fold (gsi, repl);
> + return true;
> + }
> +
> + return false;
> + }
> +
> tree len;
> tree strlen_fn = builtin_decl_implicit (BUILT_IN_STRLEN);
>
> @@ -2947,11 +2999,13 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi)
> gimple_call_arg (stmt, 1));
> case BUILT_IN_STRNCAT:
> return gimple_fold_builtin_strncat (gsi);
> +
> + case BUILT_IN_INDEX:
> case BUILT_IN_STRCHR:
> - if (gimple_fold_builtin_strchr (gsi))
> - return true;
> - /* Perform additional folding in builtin.c. */
> - break;
> + return gimple_fold_builtin_strchr (gsi, false);
> + case BUILT_IN_RINDEX:
> + case BUILT_IN_STRRCHR:
> + return gimple_fold_builtin_strchr (gsi, true);
> case BUILT_IN_FPUTS:
> return gimple_fold_builtin_fputs (gsi, gimple_call_arg (stmt, 0),
> gimple_call_arg (stmt, 1), false);
>
