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Fold __builtin_memchr function

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* builtins.h(target_char_cst_p): Declare the function.
	* builtins.c (fold_builtin_memchr): Remove.
	(target_char_cst_p): Move the function from gimple-fold.c.
	(fold_builtin_3): Do not call the function.
	* gimple-fold.c (gimple_fold_builtin_memchr): New function.
	(gimple_fold_builtin): Call the function.
	* fold-const-call.c (fold_const_call_1): Handle CFN_BUILT_IN_MEMCHR.

From-SVN: r241160
This commit is contained in:
Martin Liska 2016-10-14 14:09:51 +02:00 committed by Martin Liska
parent a918bfbf3c
commit 488c624747
5 changed files with 119 additions and 59 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2016-10-14 Martin Liska <mliska@suse.cz>
* builtins.h(target_char_cst_p): Declare the function.
* builtins.c (fold_builtin_memchr): Remove.
(target_char_cst_p): Move the function from gimple-fold.c.
(fold_builtin_3): Do not call the function.
* gimple-fold.c (gimple_fold_builtin_memchr): New function.
(gimple_fold_builtin): Call the function.
* fold-const-call.c (fold_const_call_1): Handle CFN_BUILT_IN_MEMCHR.
2016-10-14 Martin Liska <mliska@suse.cz>
* builtins.c (fold_builtin_strcmp): Remove function.

59
gcc/builtins.c
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@ -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_memchr (location_t, tree, tree, tree, tree);
static tree fold_builtin_memcmp (location_t, tree, tree, tree);
static tree fold_builtin_isascii (location_t, tree);
static tree fold_builtin_toascii (location_t, tree);
@ -7242,47 +7241,6 @@ fold_builtin_sincos (location_t loc,
fold_build1_loc (loc, REALPART_EXPR, type, call)));
}
/* Fold function call to builtin memchr. ARG1, ARG2 and LEN are the
arguments to the call, and TYPE is its return type.
Return NULL_TREE if no simplification can be made. */
static tree
fold_builtin_memchr (location_t loc, tree arg1, tree arg2, tree len, tree type)
{
if (!validate_arg (arg1, POINTER_TYPE)
|| !validate_arg (arg2, INTEGER_TYPE)
|| !validate_arg (len, INTEGER_TYPE))
return NULL_TREE;
else
{
const char *p1;
if (TREE_CODE (arg2) != INTEGER_CST
|| !tree_fits_uhwi_p (len))
return NULL_TREE;
p1 = c_getstr (arg1);
if (p1 && compare_tree_int (len, strlen (p1) + 1) <= 0)
{
char c;
const char *r;
tree tem;
if (target_char_cast (arg2, &c))
return NULL_TREE;
r = (const char *) memchr (p1, c, tree_to_uhwi (len));
if (r == NULL)
return build_int_cst (TREE_TYPE (arg1), 0);
tem = fold_build_pointer_plus_hwi_loc (loc, arg1, r - p1);
return fold_convert_loc (loc, type, tem);
}
return NULL_TREE;
}
}
/* Fold function call to builtin memcmp with arguments ARG1 and ARG2.
Return NULL_TREE if no simplification can be made. */
@ -8338,9 +8296,6 @@ fold_builtin_3 (location_t loc, tree fndecl,
return do_mpfr_remquo (arg0, arg1, arg2);
break;
case BUILT_IN_MEMCHR:
return fold_builtin_memchr (loc, arg0, arg1, arg2, type);
case BUILT_IN_BCMP:
case BUILT_IN_MEMCMP:
return fold_builtin_memcmp (loc, arg0, arg1, arg2);;
@ -9906,3 +9861,17 @@ is_inexpensive_builtin (tree decl)
return false;
}
/* 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. */
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;
}

1
gcc/builtins.h
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@ -97,6 +97,7 @@ extern unsigned HOST_WIDE_INT target_percent;
extern char target_percent_s[3];
extern char target_percent_c[3];
extern char target_percent_s_newline[4];
extern bool target_char_cst_p (tree t, char *p);
extern internal_fn associated_internal_fn (tree);
extern internal_fn replacement_internal_fn (gcall *);

31
gcc/fold-const-call.c
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@ -28,6 +28,7 @@ along with GCC; see the file COPYING3. If not see
#include "fold-const-call.h"
#include "case-cfn-macros.h"
#include "tm.h" /* For C[LT]Z_DEFINED_AT_ZERO. */
#include "builtins.h"
/* Functions that test for certain constant types, abstracting away the
decision about whether to check for overflow. */
@ -1463,6 +1464,36 @@ fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
return NULL_TREE;
}
switch (fn)
{
case CFN_BUILT_IN_MEMCHR:
{
char c;
if (integer_zerop (arg2)
&& !TREE_SIDE_EFFECTS (arg0)
&& !TREE_SIDE_EFFECTS (arg1))
return build_int_cst (type, 0);
if (!tree_fits_uhwi_p (arg2) || !target_char_cst_p (arg1, &c))
return NULL_TREE;
unsigned HOST_WIDE_INT length = tree_to_uhwi (arg2);
unsigned HOST_WIDE_INT string_length;
const char *p1 = c_getstr (arg0, &string_length);
if (p1)
{
const char *r
= (const char *)memchr (p1, c, MIN (length, string_length));
if (r == NULL && length <= string_length)
return build_int_cst (type, 0);
}
break;
}
default:
break;
}
return NULL_TREE;
}

77
gcc/gimple-fold.c
View File

@ -57,20 +57,6 @@ along with GCC; see the file COPYING3. If not see
#include "tree-cfg.h"
#include "fold-const-call.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
@ -1967,6 +1953,67 @@ gimple_fold_builtin_string_compare (gimple_stmt_iterator *gsi)
return false;
}
/* Fold a call to the memchr pointed by GSI iterator. */
static bool
gimple_fold_builtin_memchr (gimple_stmt_iterator *gsi)
{
gimple *stmt = gsi_stmt (*gsi);
tree lhs = gimple_call_lhs (stmt);
tree arg1 = gimple_call_arg (stmt, 0);
tree arg2 = gimple_call_arg (stmt, 1);
tree len = gimple_call_arg (stmt, 2);
/* If the LEN parameter is zero, return zero. */
if (integer_zerop (len))
{
replace_call_with_value (gsi, build_int_cst (ptr_type_node, 0));
return true;
}
char c;
if (TREE_CODE (arg2) != INTEGER_CST
|| !tree_fits_uhwi_p (len)
|| !target_char_cst_p (arg2, &c))
return false;
unsigned HOST_WIDE_INT length = tree_to_uhwi (len);
unsigned HOST_WIDE_INT string_length;
const char *p1 = c_getstr (arg1, &string_length);
if (p1)
{
const char *r = (const char *)memchr (p1, c, MIN (length, string_length));
if (r == NULL)
{
if (length <= string_length)
{
replace_call_with_value (gsi, build_int_cst (ptr_type_node, 0));
return true;
}
}
else
{
unsigned HOST_WIDE_INT offset = r - p1;
gimple_seq stmts = NULL;
if (lhs != NULL_TREE)
{
tree offset_cst = build_int_cst (TREE_TYPE (len), offset);
gassign *stmt = gimple_build_assign (lhs, POINTER_PLUS_EXPR,
arg1, offset_cst);
gimple_seq_add_stmt_without_update (&stmts, stmt);
}
else
gimple_seq_add_stmt_without_update (&stmts,
gimple_build_nop ());
gsi_replace_with_seq_vops (gsi, stmts);
return true;
}
}
return false;
}
/* Fold a call to the fputs builtin. ARG0 and ARG1 are the arguments
to the call. IGNORE is true if the value returned
@ -3194,6 +3241,8 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi)
case BUILT_IN_STRNCMP:
case BUILT_IN_STRNCASECMP:
return gimple_fold_builtin_string_compare (gsi);
case BUILT_IN_MEMCHR:
return gimple_fold_builtin_memchr (gsi);
case BUILT_IN_FPUTS:
return gimple_fold_builtin_fputs (gsi, gimple_call_arg (stmt, 0),
gimple_call_arg (stmt, 1), false);