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authorQing Zhao <qing.zhao@oracle.com>2018-05-31 20:01:42 +0000
committerQing Zhao <qinzhao@gcc.gnu.org>2018-05-31 20:01:42 +0000
commit8b0b334af3439179947522206b2478a28b908e61 (patch)
tree1788b6670d6db9169fdfad6b15c80815fe4af24d /gcc
parent28c84b6247e1ff5f3c7aa4c4912c361012fa3904 (diff)
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2nd Patch for PR78009
Patch for PR83026 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78809 Inline strcmp with small constant strings https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83026 missing strlen optimization for strcmp of unequal strings The design doc for PR78809 is at: https://www.mail-archive.com/gcc@gcc.gnu.org/msg83822.html this patch is for the second part of change of PR78809 and PR83026: B. for strncmp (s1, s2, n) (!)= 0 or strcmp (s1, s2) (!)= 0 B.1. (PR83026) When the lengths of both arguments are constant and it's a strcmp: * if the lengths are NOT equal, we can safely fold the call to a non-zero value. * otherwise, do nothing now. B.2. (PR78809) When the length of one argument is constant, try to replace the call with a __builtin_str(n)cmp_eq call where possible, i.e: strncmp (s, STR, C) (!)= 0 in which, s is a pointer to a string, STR is a string with constant length, C is a constant. if (C <= strlen(STR) && sizeof_array(s) > C) { replace this call with __builtin_strncmp_eq (s, STR, C) (!)= 0 } if (C > strlen(STR) { it can be safely treated as a call to strcmp (s, STR) (!)= 0 can handled by the following strcmp. } strcmp (s, STR) (!)= 0 in which, s is a pointer to a string, STR is a string with constant length. if (sizeof_array(s) > strlen(STR)) { replace this call with __builtin_strcmp_eq (s, STR, strlen(STR)+1) (!)= 0 } later when expanding the new __builtin_str(n)cmp_eq calls, first expand them as __builtin_memcmp_eq, if the expansion does not succeed, change them back to call to __builtin_str(n)cmp. adding test case strcmpopt_2.c and strcmpopt_4.c into gcc.dg for part B of PR78809 adding test case strcmpopt_3.c into gcc.dg for PR83026 From-SVN: r261039
Diffstat (limited to 'gcc')
-rw-r--r--gcc/ChangeLog22
-rw-r--r--gcc/builtins.c33
-rw-r--r--gcc/builtins.def5
-rw-r--r--gcc/gimple-fold.c5
-rw-r--r--gcc/testsuite/ChangeLog9
-rw-r--r--gcc/testsuite/gcc.dg/strcmpopt_2.c67
-rw-r--r--gcc/testsuite/gcc.dg/strcmpopt_3.c31
-rw-r--r--gcc/testsuite/gcc.dg/strcmpopt_4.c16
-rw-r--r--gcc/tree-ssa-strlen.c304
-rw-r--r--gcc/tree-ssa-structalias.c2
-rw-r--r--gcc/tree.c8
11 files changed, 485 insertions, 17 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 09c8b7c..370344c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,25 @@
+2018-05-31 Qing Zhao <qing.zhao@oracle.com>
+
+ PR middle-end/78809
+ PR middle-end/83026
+ * builtins.c (expand_builtin): Add the handling of BUILT_IN_STRCMP_EQ
+ and BUILT_IN_STRNCMP_EQ.
+ * builtins.def: Add new builtins BUILT_IN_STRCMP_EQ and
+ BUILT_IN_STRNCMP_EQ.
+ * gimple-fold.c (gimple_fold_builtin_string_compare): Add the
+ handling of BUILTIN_IN_STRCMP_EQ and BUILT_IN_STRNCMP_EQ.
+ (gimple_fold_builtin): Likewise.
+ * tree-ssa-strlen.c (compute_string_length): New function.
+ (determine_min_obsize): New function.
+ (handle_builtin_string_cmp): New function to handle calls to
+ string compare functions.
+ (strlen_optimize_stmt): Add handling to builtin string compare
+ calls.
+ * tree-ssa-structalias.c (find_func_aliases_for_builtin_call):
+ Add the handling of BUILT_IN_STRCMP_EQ and BUILT_IN_STRNCMP_EQ.
+ * tree.c (build_common_builtin_nodes): Add new defines of
+ BUILT_IN_STRNCMP_EQ and BUILT_IN_STRCMP_EQ.
+
2018-05-31 Jakub Jelinek <jakub@redhat.com>
PR target/85984
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 9741939..c96ac38 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7139,12 +7139,45 @@ expand_builtin (tree exp, rtx target, rtx subtarget, machine_mode mode,
return target;
break;
+ /* Expand it as BUILT_IN_MEMCMP_EQ first. If not successful, change it
+ back to a BUILT_IN_STRCMP. Remember to delete the 3rd paramater
+ when changing it to a strcmp call. */
+ case BUILT_IN_STRCMP_EQ:
+ target = expand_builtin_memcmp (exp, target, true);
+ if (target)
+ return target;
+
+ /* Change this call back to a BUILT_IN_STRCMP. */
+ TREE_OPERAND (exp, 1)
+ = build_fold_addr_expr (builtin_decl_explicit (BUILT_IN_STRCMP));
+
+ /* Delete the last parameter. */
+ unsigned int i;
+ vec<tree, va_gc> *arg_vec;
+ vec_alloc (arg_vec, 2);
+ for (i = 0; i < 2; i++)
+ arg_vec->quick_push (CALL_EXPR_ARG (exp, i));
+ exp = build_call_vec (TREE_TYPE (exp), CALL_EXPR_FN (exp), arg_vec);
+ /* FALLTHROUGH */
+
case BUILT_IN_STRCMP:
target = expand_builtin_strcmp (exp, target);
if (target)
return target;
break;
+ /* Expand it as BUILT_IN_MEMCMP_EQ first. If not successful, change it
+ back to a BUILT_IN_STRNCMP. */
+ case BUILT_IN_STRNCMP_EQ:
+ target = expand_builtin_memcmp (exp, target, true);
+ if (target)
+ return target;
+
+ /* Change it back to a BUILT_IN_STRNCMP. */
+ TREE_OPERAND (exp, 1)
+ = build_fold_addr_expr (builtin_decl_explicit (BUILT_IN_STRNCMP));
+ /* FALLTHROUGH */
+
case BUILT_IN_STRNCMP:
target = expand_builtin_strncmp (exp, target, mode);
if (target)
diff --git a/gcc/builtins.def b/gcc/builtins.def
index 449d08d..58b4698 100644
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -971,6 +971,11 @@ DEF_BUILTIN_STUB (BUILT_IN_ALLOCA_WITH_ALIGN_AND_MAX, "__builtin_alloca_with_ali
equality with zero. */
DEF_BUILTIN_STUB (BUILT_IN_MEMCMP_EQ, "__builtin_memcmp_eq")
+/* An internal version of strcmp/strncmp, used when the result is only
+ tested for equality with zero. */
+DEF_BUILTIN_STUB (BUILT_IN_STRCMP_EQ, "__builtin_strcmp_eq")
+DEF_BUILTIN_STUB (BUILT_IN_STRNCMP_EQ, "__builtin_strncmp_eq")
+
/* Object size checking builtins. */
DEF_GCC_BUILTIN (BUILT_IN_OBJECT_SIZE, "object_size", BT_FN_SIZE_CONST_PTR_INT, ATTR_PURE_NOTHROW_LEAF_LIST)
DEF_EXT_LIB_BUILTIN_CHKP (BUILT_IN_MEMCPY_CHK, "__memcpy_chk", BT_FN_PTR_PTR_CONST_PTR_SIZE_SIZE, ATTR_RET1_NOTHROW_NONNULL_LEAF)
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index cd1ab80..9bbe7f1 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -2215,12 +2215,14 @@ gimple_fold_builtin_string_compare (gimple_stmt_iterator *gsi)
switch (fcode)
{
case BUILT_IN_STRCMP:
+ case BUILT_IN_STRCMP_EQ:
{
r = strcmp (p1, p2);
known_result = true;
break;
}
case BUILT_IN_STRNCMP:
+ case BUILT_IN_STRNCMP_EQ:
{
if (length == -1)
break;
@@ -2254,6 +2256,7 @@ gimple_fold_builtin_string_compare (gimple_stmt_iterator *gsi)
bool nonzero_length = length >= 1
|| fcode == BUILT_IN_STRCMP
+ || fcode == BUILT_IN_STRCMP_EQ
|| fcode == BUILT_IN_STRCASECMP;
location_t loc = gimple_location (stmt);
@@ -3687,8 +3690,10 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi)
case BUILT_IN_STRSTR:
return gimple_fold_builtin_strstr (gsi);
case BUILT_IN_STRCMP:
+ case BUILT_IN_STRCMP_EQ:
case BUILT_IN_STRCASECMP:
case BUILT_IN_STRNCMP:
+ case BUILT_IN_STRNCMP_EQ:
case BUILT_IN_STRNCASECMP:
return gimple_fold_builtin_string_compare (gsi);
case BUILT_IN_MEMCHR:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e0745e0..677d8e0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2018-05-31 Qing Zhao <qing.zhao@oracle.com>
+
+ PR middle-end/78809
+ * gcc.dg/strcmpopt_2.c: New test.
+ * gcc.dg/strcmpopt_3.c: New test.
+
+ PR middle-end/83026
+ * gcc.dg/strcmpopt_3.c: New test.
+
2018-05-31 Jakub Jelinek <jakub@redhat.com>
PR target/85984
diff --git a/gcc/testsuite/gcc.dg/strcmpopt_2.c b/gcc/testsuite/gcc.dg/strcmpopt_2.c
new file mode 100644
index 0000000..0131b8f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strcmpopt_2.c
@@ -0,0 +1,67 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+char s[100] = {'a','b','c','d'};
+typedef struct { char s[8]; int x; } S;
+
+__attribute__ ((noinline)) int
+f1 (S *s)
+{
+ return __builtin_strcmp (s->s, "abc") != 0;
+}
+
+__attribute__ ((noinline)) int
+f2 (void)
+{
+ return __builtin_strcmp (s, "abc") != 0;
+}
+
+__attribute__ ((noinline)) int
+f3 (S *s)
+{
+ return __builtin_strcmp ("abc", s->s) != 0;
+}
+
+__attribute__ ((noinline)) int
+f4 (void)
+{
+ return __builtin_strcmp ("abc", s) != 0;
+}
+
+__attribute__ ((noinline)) int
+f5 (S *s)
+{
+ return __builtin_strncmp (s->s, "abc", 3) != 0;
+}
+
+__attribute__ ((noinline)) int
+f6 (void)
+{
+ return __builtin_strncmp (s, "abc", 2) != 0;
+}
+
+__attribute__ ((noinline)) int
+f7 (S *s)
+{
+ return __builtin_strncmp ("abc", s->s, 3) != 0;
+}
+
+__attribute__ ((noinline)) int
+f8 (void)
+{
+ return __builtin_strncmp ("abc", s, 2) != 0;
+}
+
+int main (void)
+{
+ S ss = {{'a','b','c'}, 2};
+
+ if (f1 (&ss) != 0 || f2 () != 1 || f3 (&ss) != 0 ||
+ f4 () != 1 || f5 (&ss) != 0 || f6 () != 0 ||
+ f7 (&ss) != 0 || f8 () != 0)
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "cmp_eq \\(" 8 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strcmpopt_3.c b/gcc/testsuite/gcc.dg/strcmpopt_3.c
new file mode 100644
index 0000000..86a0d7a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strcmpopt_3.c
@@ -0,0 +1,31 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+__attribute__ ((noinline)) int
+f1 (void)
+{
+ char *s0= "abcd";
+ char s[8];
+ __builtin_strcpy (s, s0);
+ return __builtin_strcmp(s, "abc") != 0;
+}
+
+__attribute__ ((noinline)) int
+f2 (void)
+{
+ char *s0 = "ab";
+ char s[8];
+ __builtin_strcpy (s, s0);
+ return __builtin_strcmp("abc", s) != 0;
+}
+
+int main (void)
+{
+ if (f1 () != 1
+ || f2 () != 1)
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "strcmp" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strcmpopt_4.c b/gcc/testsuite/gcc.dg/strcmpopt_4.c
new file mode 100644
index 0000000..d727bc3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strcmpopt_4.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+typedef struct { char s[8]; int x; } S;
+extern int max_i;
+
+int
+f1 (S * s)
+{
+ int result, i;
+ for (i = 0; i < max_i; i++)
+ result += __builtin_strcmp (s->s, "abc") != 0 ? 2 : 1;
+ return result;
+}
+
+/* { dg-final { scan-tree-dump-times "cmp_eq \\(" 1 "strlen" } } */
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index 556c5bc..7a89174 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -48,6 +48,7 @@ along with GCC; see the file COPYING3. If not see
#include "params.h"
#include "ipa-chkp.h"
#include "tree-hash-traits.h"
+#include "tree-object-size.h"
#include "builtins.h"
#include "target.h"
#include "diagnostic-core.h"
@@ -2627,27 +2628,28 @@ handle_builtin_malloc (enum built_in_function bcode, gimple_stmt_iterator *gsi)
/* Handle a call to memset.
After a call to calloc, memset(,0,) is unnecessary.
- memset(malloc(n),0,n) is calloc(n,1). */
+ memset(malloc(n),0,n) is calloc(n,1).
+ return true when the call is transfomred, false otherwise. */
static bool
handle_builtin_memset (gimple_stmt_iterator *gsi)
{
gimple *stmt2 = gsi_stmt (*gsi);
if (!integer_zerop (gimple_call_arg (stmt2, 1)))
- return true;
+ return false;
tree ptr = gimple_call_arg (stmt2, 0);
int idx1 = get_stridx (ptr);
if (idx1 <= 0)
- return true;
+ return false;
strinfo *si1 = get_strinfo (idx1);
if (!si1)
- return true;
+ return false;
gimple *stmt1 = si1->stmt;
if (!stmt1 || !is_gimple_call (stmt1))
- return true;
+ return false;
tree callee1 = gimple_call_fndecl (stmt1);
if (!valid_builtin_call (stmt1))
- return true;
+ return false;
enum built_in_function code1 = DECL_FUNCTION_CODE (callee1);
tree size = gimple_call_arg (stmt2, 2);
if (code1 == BUILT_IN_CALLOC)
@@ -2663,7 +2665,7 @@ handle_builtin_memset (gimple_stmt_iterator *gsi)
si1->stmt = gsi_stmt (gsi1);
}
else
- return true;
+ return false;
tree lhs = gimple_call_lhs (stmt2);
unlink_stmt_vdef (stmt2);
if (lhs)
@@ -2677,12 +2679,13 @@ handle_builtin_memset (gimple_stmt_iterator *gsi)
release_defs (stmt2);
}
- return false;
+ return true;
}
/* Handle a call to memcmp. We try to handle small comparisons by
converting them to load and compare, and replacing the call to memcmp
- with a __builtin_memcmp_eq call where possible. */
+ with a __builtin_memcmp_eq call where possible.
+ return true when call is transformed, return false otherwise. */
static bool
handle_builtin_memcmp (gimple_stmt_iterator *gsi)
@@ -2697,7 +2700,7 @@ handle_builtin_memcmp (gimple_stmt_iterator *gsi)
imm_use_iterator iter;
if (!res)
- return true;
+ return false;
FOR_EACH_IMM_USE_FAST (use_p, iter, res)
{
@@ -2711,17 +2714,17 @@ handle_builtin_memcmp (gimple_stmt_iterator *gsi)
tree_code code = gimple_assign_rhs_code (asgn);
if ((code != EQ_EXPR && code != NE_EXPR)
|| !integer_zerop (gimple_assign_rhs2 (asgn)))
- return true;
+ return false;
}
else if (gimple_code (ustmt) == GIMPLE_COND)
{
tree_code code = gimple_cond_code (ustmt);
if ((code != EQ_EXPR && code != NE_EXPR)
|| !integer_zerop (gimple_cond_rhs (ustmt)))
- return true;
+ return false;
}
else
- return true;
+ return false;
}
if (tree_fits_uhwi_p (len)
@@ -2756,12 +2759,274 @@ handle_builtin_memcmp (gimple_stmt_iterator *gsi)
boolean_type_node,
arg1, arg2));
gimplify_and_update_call_from_tree (gsi, res);
- return false;
+ return true;
}
}
gimple_call_set_fndecl (stmt2, builtin_decl_explicit (BUILT_IN_MEMCMP_EQ));
- return false;
+ return true;
+}
+
+/* Given an index to the strinfo vector, compute the string length for the
+ corresponding string. Return -1 when unknown. */
+
+static HOST_WIDE_INT
+compute_string_length (int idx)
+{
+ HOST_WIDE_INT string_leni = -1;
+ gcc_assert (idx != 0);
+
+ if (idx < 0)
+ return ~idx;
+
+ strinfo *si = get_strinfo (idx);
+ if (si)
+ {
+ tree const_string_len = get_string_length (si);
+ if (const_string_len && tree_fits_shwi_p (const_string_len))
+ string_leni = tree_to_shwi (const_string_len);
+ }
+
+ if (string_leni < 0)
+ return -1;
+
+ return string_leni;
+}
+
+/* Determine the minimum size of the object referenced by DEST expression which
+ must have a pointer type.
+ Return the minimum size of the object if successful or NULL when the size
+ cannot be determined. */
+static tree
+determine_min_objsize (tree dest)
+{
+ unsigned HOST_WIDE_INT size = 0;
+
+ if (compute_builtin_object_size (dest, 2, &size))
+ return build_int_cst (sizetype, size);
+
+ /* Try to determine the size of the object through the RHS of the
+ assign statement. */
+ if (TREE_CODE (dest) == SSA_NAME)
+ {
+ gimple *stmt = SSA_NAME_DEF_STMT (dest);
+ if (!is_gimple_assign (stmt))
+ return NULL_TREE;
+
+ if (!gimple_assign_single_p (stmt)
+ && !gimple_assign_unary_nop_p (stmt))
+ return NULL_TREE;
+
+ dest = gimple_assign_rhs1 (stmt);
+ return determine_min_objsize (dest);
+ }
+
+ /* Try to determine the size of the object from its type. */
+ if (TREE_CODE (dest) != ADDR_EXPR)
+ return NULL_TREE;
+
+ tree type = TREE_TYPE (dest);
+ if (TREE_CODE (type) == POINTER_TYPE)
+ type = TREE_TYPE (type);
+
+ type = TYPE_MAIN_VARIANT (type);
+
+ /* We cannot determine the size of the array if it's a flexible array,
+ which is declared at the end of a structure. */
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && !array_at_struct_end_p (dest))
+ {
+ tree size_t = TYPE_SIZE_UNIT (type);
+ if (size_t && TREE_CODE (size_t) == INTEGER_CST
+ && !integer_zerop (size_t))
+ return size_t;
+ }
+
+ return NULL_TREE;
+}
+
+/* Handle a call to strcmp or strncmp. When the result is ONLY used to do
+ equality test against zero:
+
+ A. When the lengths of both arguments are constant and it's a strcmp:
+ * if the lengths are NOT equal, we can safely fold the call
+ to a non-zero value.
+ * otherwise, do nothing now.
+
+ B. When the length of one argument is constant, try to replace the call with
+ a __builtin_str(n)cmp_eq call where possible, i.e:
+
+ strncmp (s, STR, C) (!)= 0 in which, s is a pointer to a string, STR is a
+ string with constant length , C is a constant.
+ if (C <= strlen(STR) && sizeof_array(s) > C)
+ {
+ replace this call with
+ strncmp_eq (s, STR, C) (!)= 0
+ }
+ if (C > strlen(STR)
+ {
+ it can be safely treated as a call to strcmp (s, STR) (!)= 0
+ can handled by the following strcmp.
+ }
+
+ strcmp (s, STR) (!)= 0 in which, s is a pointer to a string, STR is a
+ string with constant length.
+ if (sizeof_array(s) > strlen(STR))
+ {
+ replace this call with
+ strcmp_eq (s, STR, strlen(STR)+1) (!)= 0
+ }
+
+ Return true when the call is transformed, return false otherwise.
+ */
+
+static bool
+handle_builtin_string_cmp (gimple_stmt_iterator *gsi)
+{
+ gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
+ tree res = gimple_call_lhs (stmt);
+ use_operand_p use_p;
+ imm_use_iterator iter;
+ tree arg1 = gimple_call_arg (stmt, 0);
+ tree arg2 = gimple_call_arg (stmt, 1);
+ int idx1 = get_stridx (arg1);
+ int idx2 = get_stridx (arg2);
+ HOST_WIDE_INT length = -1;
+ bool is_ncmp = false;
+
+ if (!res)
+ return false;
+
+ /* When both arguments are unknown, do nothing. */
+ if (idx1 == 0 && idx2 == 0)
+ return false;
+
+ /* Handle strncmp function. */
+ if (gimple_call_num_args (stmt) == 3)
+ {
+ tree len = gimple_call_arg (stmt, 2);
+ if (tree_fits_shwi_p (len))
+ length = tree_to_shwi (len);
+
+ is_ncmp = true;
+ }
+
+ /* For strncmp, if the length argument is NOT known, do nothing. */
+ if (is_ncmp && length < 0)
+ return false;
+
+ /* When the result is ONLY used to do equality test against zero. */
+ FOR_EACH_IMM_USE_FAST (use_p, iter, res)
+ {
+ gimple *use_stmt = USE_STMT (use_p);
+
+ if (is_gimple_debug (use_stmt))
+ continue;
+ if (gimple_code (use_stmt) == GIMPLE_ASSIGN)
+ {
+ tree_code code = gimple_assign_rhs_code (use_stmt);
+ if (code == COND_EXPR)
+ {
+ tree cond_expr = gimple_assign_rhs1 (use_stmt);
+ if ((TREE_CODE (cond_expr) != EQ_EXPR
+ && (TREE_CODE (cond_expr) != NE_EXPR))
+ || !integer_zerop (TREE_OPERAND (cond_expr, 1)))
+ return false;
+ }
+ else if (code == EQ_EXPR || code == NE_EXPR)
+ {
+ if (!integer_zerop (gimple_assign_rhs2 (use_stmt)))
+ return false;
+ }
+ else
+ return false;
+ }
+ else if (gimple_code (use_stmt) == GIMPLE_COND)
+ {
+ tree_code code = gimple_cond_code (use_stmt);
+ if ((code != EQ_EXPR && code != NE_EXPR)
+ || !integer_zerop (gimple_cond_rhs (use_stmt)))
+ return false;
+ }
+ else
+ return false;
+ }
+
+ /* When the lengths of both arguments are known, and they are unequal, we can
+ safely fold the call to a non-zero value for strcmp;
+ othewise, do nothing now. */
+ if (idx1 != 0 && idx2 != 0)
+ {
+ HOST_WIDE_INT const_string_leni1 = compute_string_length (idx1);
+ HOST_WIDE_INT const_string_leni2 = compute_string_length (idx2);
+
+ if (!is_ncmp
+ && const_string_leni1 != -1
+ && const_string_leni2 != -1
+ && const_string_leni1 != const_string_leni2)
+ {
+ replace_call_with_value (gsi, integer_one_node);
+ return true;
+ }
+ return false;
+ }
+
+ /* When the length of one argument is constant. */
+ tree var_string = NULL_TREE;
+ HOST_WIDE_INT const_string_leni = -1;
+
+ if (idx1)
+ {
+ const_string_leni = compute_string_length (idx1);
+ var_string = arg2;
+ }
+ else
+ {
+ gcc_checking_assert (idx2);
+ const_string_leni = compute_string_length (idx2);
+ var_string = arg1;
+ }
+
+ if (const_string_leni < 0)
+ return false;
+
+ unsigned HOST_WIDE_INT var_sizei = 0;
+ /* try to determine the minimum size of the object pointed by var_string. */
+ tree size = determine_min_objsize (var_string);
+
+ if (!size)
+ return false;
+
+ if (tree_fits_uhwi_p (size))
+ var_sizei = tree_to_uhwi (size);
+
+ if (var_sizei == 0)
+ return false;
+
+ /* For strncmp, if length > const_string_leni , this call can be safely
+ transformed to a strcmp. */
+ if (is_ncmp && length > const_string_leni)
+ is_ncmp = false;
+
+ unsigned HOST_WIDE_INT final_length
+ = is_ncmp ? length : const_string_leni + 1;
+
+ /* Replace strcmp or strncmp with the corresponding str(n)cmp_eq. */
+ if (var_sizei > final_length)
+ {
+ tree fn
+ = (is_ncmp
+ ? builtin_decl_implicit (BUILT_IN_STRNCMP_EQ)
+ : builtin_decl_implicit (BUILT_IN_STRCMP_EQ));
+ if (!fn)
+ return false;
+ tree const_string_len = build_int_cst (size_type_node, final_length);
+ update_gimple_call (gsi, fn, 3, arg1, arg2, const_string_len);
+ }
+ else
+ return false;
+
+ return true;
}
/* Handle a POINTER_PLUS_EXPR statement.
@@ -3209,11 +3474,16 @@ strlen_check_and_optimize_stmt (gimple_stmt_iterator *gsi, bool *cleanup_eh)
handle_builtin_malloc (DECL_FUNCTION_CODE (callee), gsi);
break;
case BUILT_IN_MEMSET:
- if (!handle_builtin_memset (gsi))
+ if (handle_builtin_memset (gsi))
return false;
break;
case BUILT_IN_MEMCMP:
- if (!handle_builtin_memcmp (gsi))
+ if (handle_builtin_memcmp (gsi))
+ return false;
+ break;
+ case BUILT_IN_STRCMP:
+ case BUILT_IN_STRNCMP:
+ if (handle_builtin_string_cmp (gsi))
return false;
break;
default:
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 8fb13a0..14ab83a 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -4498,7 +4498,9 @@ find_func_aliases_for_builtin_call (struct function *fn, gcall *t)
that use the memory pointed to by their arguments (but not
transitively). */
case BUILT_IN_STRCMP:
+ case BUILT_IN_STRCMP_EQ:
case BUILT_IN_STRNCMP:
+ case BUILT_IN_STRNCMP_EQ:
case BUILT_IN_STRCASECMP:
case BUILT_IN_STRNCASECMP:
case BUILT_IN_MEMCMP:
diff --git a/gcc/tree.c b/gcc/tree.c
index e8dc425..85ce993 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -10277,6 +10277,14 @@ build_common_builtin_nodes (void)
"__builtin_memcmp_eq",
ECF_PURE | ECF_NOTHROW | ECF_LEAF);
+ local_define_builtin ("__builtin_strncmp_eq", ftype, BUILT_IN_STRNCMP_EQ,
+ "__builtin_strncmp_eq",
+ ECF_PURE | ECF_NOTHROW | ECF_LEAF);
+
+ local_define_builtin ("__builtin_strcmp_eq", ftype, BUILT_IN_STRCMP_EQ,
+ "__builtin_strcmp_eq",
+ ECF_PURE | ECF_NOTHROW | ECF_LEAF);
+
/* If there's a possibility that we might use the ARM EABI, build the
alternate __cxa_end_cleanup node used to resume from C++. */
if (targetm.arm_eabi_unwinder)