PR middle-end/95673 - missing -Wstring-compare for an impossible strncmp test
gcc/ChangeLog: PR middle-end/95673 * tree-ssa-strlen.c (used_only_for_zero_equality): Rename... (use_in_zero_equality): ...to this. Add a default argument. (handle_builtin_memcmp): Adjust to the name change above. (handle_builtin_string_cmp): Same. (maybe_warn_pointless_strcmp): Same. Pass in an explicit argument. gcc/testsuite/ChangeLog: PR middle-end/95673 * gcc.dg/Wstring-compare-3.c: New test.
This commit is contained in:
Martin Sebor
parent
f8e4c55cbc
commit
b1ecb86569
|
|
@ -0,0 +1,106 @@
|
|||
/* PR middle-end/95673 - missing -Wstring-compare for an impossible strncmp test
|
||||
{ dg-do compile }
|
||||
{ dg-options "-O2 -Wall -Wstring-compare -ftrack-macro-expansion=0" } */
|
||||
|
||||
typedef __SIZE_TYPE__ size_t;
|
||||
|
||||
extern int strcmp (const char*, const char*);
|
||||
extern int strncmp (const char*, const char*, size_t);
|
||||
|
||||
void sink (int, ...);
|
||||
|
||||
extern char a3[3];
|
||||
|
||||
int nowarn_strcmp_one_use_ltz (int c)
|
||||
{
|
||||
const char *s = c ? "1234" : a3;
|
||||
int n = strcmp (s, "123");
|
||||
return n < 0;
|
||||
}
|
||||
|
||||
|
||||
int nowarn_strcmp_one_use_eqnz (int c)
|
||||
{
|
||||
const char *s = c ? "12345" : a3;
|
||||
int n = strcmp (s, "123");
|
||||
return n == 1;
|
||||
}
|
||||
|
||||
|
||||
int warn_strcmp_one_use_eqz (int c)
|
||||
{
|
||||
const char *s = c ? "123456" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
return n == 0; // { dg-message "in this expression" }
|
||||
}
|
||||
|
||||
|
||||
int warn_strcmp_one_use_bang (int c)
|
||||
{
|
||||
const char *s = c ? "1234567" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
return !n; // { dg-message "in this expression" }
|
||||
}
|
||||
|
||||
|
||||
int warn_strcmp_one_use_bang_bang (int c)
|
||||
{
|
||||
const char *s = c ? "12345678" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
return !!n; // { dg-message "in this expression" }
|
||||
}
|
||||
|
||||
|
||||
_Bool warn_one_use_bool (int c)
|
||||
{
|
||||
const char *s = c ? "123456789" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
return (_Bool)n; // { dg-message "in this expression" }
|
||||
}
|
||||
|
||||
|
||||
int warn_strcmp_one_use_cond (int c)
|
||||
{
|
||||
const char *s = c ? "1234567890" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
return n ? 3 : 5; // { dg-message "in this expression" }
|
||||
}
|
||||
|
||||
|
||||
int nowarn_strcmp_multiple_uses (int c)
|
||||
{
|
||||
const char *s = c ? "1234" : a3;
|
||||
int n = strcmp (s, "123");
|
||||
sink (n < 0);
|
||||
sink (n > 0);
|
||||
sink (n <= 0);
|
||||
sink (n >= 0);
|
||||
sink (n + 1);
|
||||
return n;
|
||||
}
|
||||
|
||||
|
||||
int warn_strcmp_multiple_uses (int c)
|
||||
{
|
||||
const char *s = c ? "12345" : a3;
|
||||
int n = strcmp (s, "123"); // { dg-warning "'strcmp' of a string of length 3 and an array of size 3 evaluates to nonzero" }
|
||||
sink (n < 0);
|
||||
sink (n > 0);
|
||||
sink (n <= 0);
|
||||
sink (n >= 0);
|
||||
sink (n == 0); // { dg-message "in this expression" }
|
||||
return n;
|
||||
}
|
||||
|
||||
|
||||
int warn_strncmp_multiple_uses (int c)
|
||||
{
|
||||
const char *s = a3;
|
||||
int n = strncmp (s, "1234", 4); // { dg-warning "'strncmp' of a string of length 4, an array of size 3 and bound of 4 evaluates to nonzero" }
|
||||
sink (n < 0);
|
||||
sink (n > 0);
|
||||
sink (n <= 0);
|
||||
sink (n >= 0);
|
||||
sink (n == 0); // { dg-message "in this expression" }
|
||||
return n;
|
||||
}
|
||||
|
|
@ -3989,11 +3989,13 @@ handle_builtin_memset (gimple_stmt_iterator *gsi, bool *zero_write,
|
|||
return true;
|
||||
}
|
||||
|
||||
/* Return a pointer to the first such equality expression if RES is used
|
||||
only in expressions testing its equality to zero, and null otherwise. */
|
||||
/* Return first such statement if RES is used in statements testing its
|
||||
equality to zero, and null otherwise. If EXCLUSIVE is true, return
|
||||
nonnull if and only RES is used in such expressions exclusively and
|
||||
in none other. */
|
||||
|
||||
static gimple *
|
||||
used_only_for_zero_equality (tree res)
|
||||
use_in_zero_equality (tree res, bool exclusive = true)
|
||||
{
|
||||
gimple *first_use = NULL;
|
||||
|
||||
|
|
@ -4006,6 +4008,7 @@ used_only_for_zero_equality (tree res)
|
|||
|
||||
if (is_gimple_debug (use_stmt))
|
||||
continue;
|
||||
|
||||
if (gimple_code (use_stmt) == GIMPLE_ASSIGN)
|
||||
{
|
||||
tree_code code = gimple_assign_rhs_code (use_stmt);
|
||||
|
|
@ -4015,25 +4018,41 @@ used_only_for_zero_equality (tree res)
|
|||
if ((TREE_CODE (cond_expr) != EQ_EXPR
|
||||
&& (TREE_CODE (cond_expr) != NE_EXPR))
|
||||
|| !integer_zerop (TREE_OPERAND (cond_expr, 1)))
|
||||
return NULL;
|
||||
{
|
||||
if (exclusive)
|
||||
return NULL;
|
||||
continue;
|
||||
}
|
||||
}
|
||||
else if (code == EQ_EXPR || code == NE_EXPR)
|
||||
{
|
||||
if (!integer_zerop (gimple_assign_rhs2 (use_stmt)))
|
||||
return NULL;
|
||||
{
|
||||
if (exclusive)
|
||||
return NULL;
|
||||
continue;
|
||||
}
|
||||
}
|
||||
else
|
||||
else if (exclusive)
|
||||
return NULL;
|
||||
else
|
||||
continue;
|
||||
}
|
||||
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 NULL;
|
||||
{
|
||||
if (exclusive)
|
||||
return NULL;
|
||||
continue;
|
||||
}
|
||||
}
|
||||
else if (exclusive)
|
||||
return NULL;
|
||||
else
|
||||
return NULL;
|
||||
continue;
|
||||
|
||||
if (!first_use)
|
||||
first_use = use_stmt;
|
||||
|
|
@ -4053,7 +4072,7 @@ handle_builtin_memcmp (gimple_stmt_iterator *gsi)
|
|||
gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
|
||||
tree res = gimple_call_lhs (stmt);
|
||||
|
||||
if (!res || !used_only_for_zero_equality (res))
|
||||
if (!res || !use_in_zero_equality (res))
|
||||
return false;
|
||||
|
||||
tree arg1 = gimple_call_arg (stmt, 0);
|
||||
|
|
@ -4317,7 +4336,7 @@ maybe_warn_pointless_strcmp (gimple *stmt, HOST_WIDE_INT bound,
|
|||
unsigned HOST_WIDE_INT siz)
|
||||
{
|
||||
tree lhs = gimple_call_lhs (stmt);
|
||||
gimple *use = used_only_for_zero_equality (lhs);
|
||||
gimple *use = use_in_zero_equality (lhs, /* exclusive = */ false);
|
||||
if (!use)
|
||||
return;
|
||||
|
||||
|
|
@ -4367,12 +4386,12 @@ maybe_warn_pointless_strcmp (gimple *stmt, HOST_WIDE_INT bound,
|
|||
stmt, callee, minlen, siz, bound);
|
||||
}
|
||||
|
||||
if (warned)
|
||||
{
|
||||
location_t use_loc = gimple_location (use);
|
||||
if (LOCATION_LINE (stmt_loc) != LOCATION_LINE (use_loc))
|
||||
inform (use_loc, "in this expression");
|
||||
}
|
||||
if (!warned)
|
||||
return;
|
||||
|
||||
location_t use_loc = gimple_location (use);
|
||||
if (LOCATION_LINE (stmt_loc) != LOCATION_LINE (use_loc))
|
||||
inform (use_loc, "in this expression");
|
||||
}
|
||||
|
||||
|
||||
|
|
@ -4507,7 +4526,7 @@ handle_builtin_string_cmp (gimple_stmt_iterator *gsi, range_query *rvals)
|
|||
/* The size of the array in which the unknown string is stored. */
|
||||
HOST_WIDE_INT varsiz = arysiz1 < 0 ? arysiz2 : arysiz1;
|
||||
|
||||
if ((varsiz < 0 || cmpsiz < varsiz) && used_only_for_zero_equality (lhs))
|
||||
if ((varsiz < 0 || cmpsiz < varsiz) && use_in_zero_equality (lhs))
|
||||
{
|
||||
/* If the known length is less than the size of the other array
|
||||
and the strcmp result is only used to test equality to zero,
|
||||
|
|
|
|||
Loading…
Reference in New Issue