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PR tree-optimization/92683 - strncmp incorrect result with equal substrings and non-const bound

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gcc/testsuite/ChangeLog:

	PR tree-optimization/92683
	* gcc.dg/strcmpopt_8.c: New test.
	* gcc.dg/strcmpopt_9.c: New test.

gcc/ChangeLog:

	PR tree-optimization/92683
	* gimple-fold.c (gimple_fold_builtin_string_compare): Restore a test
	inadvertently removed in a previous change.  Rename local variable
	for clarity.

From-SVN: r278742
This commit is contained in:
Martin Sebor 2019-11-26 23:56:22 +00:00 committed by Martin Sebor
parent e4c935cb98
commit d86d8b35dd
5 changed files with 233 additions and 5 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2019-11-26 Martin Sebor <msebor@redhat.com>
PR tree-optimization/92683
* gimple-fold.c (gimple_fold_builtin_string_compare): Restore a test
inadvertently removed in a previous change. Rename local variable
for clarity.
2019-11-26 Richard Biener <rguenther@suse.de>
PR middle-end/92669

14
gcc/gimple-fold.c
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@ -2346,18 +2346,19 @@ gimple_fold_builtin_string_compare (gimple_stmt_iterator *gsi)
tree str1 = gimple_call_arg (stmt, 0);
tree str2 = gimple_call_arg (stmt, 1);
tree lhs = gimple_call_lhs (stmt);
tree len = NULL_TREE;
tree bound_node = NULL_TREE;
unsigned HOST_WIDE_INT bound = HOST_WIDE_INT_M1U;
/* Handle strncmp and strncasecmp functions. */
if (gimple_call_num_args (stmt) == 3)
{
len = gimple_call_arg (stmt, 2);
if (tree_fits_uhwi_p (len))
bound = tree_to_uhwi (len);
bound_node = gimple_call_arg (stmt, 2);
if (tree_fits_uhwi_p (bound_node))
bound = tree_to_uhwi (bound_node);
}
/* If the LEN parameter is zero, return zero. */
/* If the BOUND parameter is zero, return zero. */
if (bound == 0)
{
replace_call_with_value (gsi, integer_zero_node);
@ -2418,6 +2419,9 @@ gimple_fold_builtin_string_compare (gimple_stmt_iterator *gsi)
case BUILT_IN_STRNCMP:
case BUILT_IN_STRNCMP_EQ:
{
if (bound == HOST_WIDE_INT_M1U)
break;
/* Reduce the bound to be no more than the length
of the shorter of the two strings, or the sizes
of the unterminated arrays. */

6
gcc/testsuite/ChangeLog
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@ -1,3 +1,9 @@
2019-11-26 Martin Sebor <msebor@redhat.com>
PR tree-optimization/92683
* gcc.dg/strcmpopt_8.c: New test.
* gcc.dg/strcmpopt_9.c: New test.
2019-11-26 Joel Hutton <Joel.Hutton@arm.com>
PR testsuite/92391

177
gcc/testsuite/gcc.dg/strcmpopt_8.c Normal file
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@ -0,0 +1,177 @@
/* PR tree-optimization/92683 - strncmp incorrect result with equal substrings
and nonconst bound
{ dg-do compile }
{ dg-options "-O1 -Wall -fdump-tree-forwprop1" } */
#define SIZE_MAX __SIZE_MAX__
#define S123 "123"
#define S1234 "1234"
typedef __SIZE_TYPE__ size_t;
#ifndef ident
# define ident(n) n
#endif
extern void failure_on_line (int);
/* Verify that the test in 'if (EQL strncmp (S, T, N))' is folded. */
#define T(eql, s, t, n) do { \
max = ident (n); \
if (!(eql __builtin_strncmp (s, t, max))) \
failure_on_line (__LINE__); \
} while (0)
void test_literal (void)
{
size_t max;
T (0 ==, S123, S1234, 0);
T (0 ==, S123, S1234, 1);
T (0 ==, S123, S1234, 2);
T (0 ==, S123, S1234, 3);
T (0 >, S123, S1234, 4);
T (0 >, S123, S1234, 5);
T (0 >, S123, S1234, SIZE_MAX - 2);
T (0 >, S123, S1234, SIZE_MAX - 1);
T (0 >, S123, S1234, SIZE_MAX);
T (0 ==, S123 + 1, S1234, 0);
T (0 <, S123 + 1, S1234, 1);
T (0 <, S123 + 1, S1234, 2);
T (0 <, S123 + 1, S1234, 3);
T (0 <, S123 + 1, S1234, 4);
T (0 <, S123 + 1, S1234, SIZE_MAX - 2);
T (0 <, S123 + 1, S1234, SIZE_MAX - 1);
T (0 <, S123 + 1, S1234, SIZE_MAX);
T (0 ==, S123 + 1, S1234 + 1, 0);
T (0 ==, S123 + 1, S1234 + 1, 1);
T (0 ==, S123 + 1, S1234 + 1, 2);
T (0 >, S123 + 1, S1234 + 1, 3);
T (0 >, S123 + 1, S1234 + 1, SIZE_MAX - 1);
T (0 >, S123 + 1, S1234 + 1, SIZE_MAX);
T (0 ==, S123 + 3, S1234 + 1, 0);
T (0 >, S123 + 3, S1234 + 1, 1);
T (0 >, S123 + 3, S1234 + 1, 2);
T (0 >, S123 + 3, S1234 + 1, 3);
T (0 >, S123 + 3, S1234 + 1, SIZE_MAX - 1);
T (0 >, S123 + 3, S1234 + 1, SIZE_MAX);
int zero = 0;
T (zero ==, S123, S1234, 0);
T (zero ==, S123, S1234, 1);
T (zero ==, S123, S1234, 2);
T (zero ==, S123, S1234, 3);
T (zero >, S123, S1234, 4);
T (zero >, S123, S1234, 5);
T (zero >, S123, S1234, SIZE_MAX - 2);
T (zero >, S123, S1234, SIZE_MAX - 1);
T (zero >, S123, S1234, SIZE_MAX);
T (zero ==, S123 + 1, S1234, 0);
T (zero <, S123 + 1, S1234, 1);
T (zero <, S123 + 1, S1234, 2);
T (zero <, S123 + 1, S1234, 3);
T (zero <, S123 + 1, S1234, 4);
T (zero <, S123 + 1, S1234, SIZE_MAX - 2);
T (zero <, S123 + 1, S1234, SIZE_MAX - 1);
T (zero <, S123 + 1, S1234, SIZE_MAX);
T (zero ==, S123 + 1, S1234 + 1, 0);
T (zero ==, S123 + 1, S1234 + 1, 1);
T (zero ==, S123 + 1, S1234 + 1, 2);
T (zero >, S123 + 1, S1234 + 1, 3);
T (zero >, S123 + 1, S1234 + 1, SIZE_MAX - 1);
T (zero >, S123 + 1, S1234 + 1, SIZE_MAX);
T (zero ==, S123 + 3, S1234 + 1, 0);
T (zero >, S123 + 3, S1234 + 1, 1);
T (zero >, S123 + 3, S1234 + 1, 2);
T (zero >, S123 + 3, S1234 + 1, 3);
T (zero >, S123 + 3, S1234 + 1, SIZE_MAX - 1);
T (zero >, S123 + 3, S1234 + 1, SIZE_MAX);
}
const char s123[] = S123;
const char s1234[] = S1234;
void test_cst_array (void)
{
size_t max;
T (0 ==, s123, s1234, 0);
T (0 ==, s123, s1234, 1);
T (0 ==, s123, s1234, 2);
T (0 ==, s123, s1234, 3);
T (0 >, s123, s1234, 4);
T (0 >, s123, s1234, 5);
T (0 >, s123, s1234, SIZE_MAX - 2);
T (0 >, s123, s1234, SIZE_MAX - 1);
T (0 >, s123, s1234, SIZE_MAX);
T (0 ==, s123 + 1, s1234, 0);
T (0 <, s123 + 1, s1234, 1);
T (0 <, s123 + 1, s1234, 2);
T (0 <, s123 + 1, s1234, 3);
T (0 <, s123 + 1, s1234, 4);
T (0 <, s123 + 1, s1234, SIZE_MAX - 2);
T (0 <, s123 + 1, s1234, SIZE_MAX - 1);
T (0 <, s123 + 1, s1234, SIZE_MAX);
T (0 ==, s123 + 1, s1234 + 1, 0);
T (0 ==, s123 + 1, s1234 + 1, 1);
T (0 ==, s123 + 1, s1234 + 1, 2);
T (0 >, s123 + 1, s1234 + 1, 3);
T (0 >, s123 + 1, s1234 + 1, SIZE_MAX - 1);
T (0 >, s123 + 1, s1234 + 1, SIZE_MAX);
T (0 ==, s123 + 3, s1234 + 1, 0);
T (0 >, s123 + 3, s1234 + 1, 1);
T (0 >, s123 + 3, s1234 + 1, 2);
T (0 >, s123 + 3, s1234 + 1, 3);
T (0 >, s123 + 3, s1234 + 1, SIZE_MAX - 1);
T (0 >, s123 + 3, s1234 + 1, SIZE_MAX);
int zero = 0;
T (zero ==, s123, s1234, 0);
T (zero ==, s123, s1234, 1);
T (zero ==, s123, s1234, 2);
T (zero ==, s123, s1234, 3);
T (zero >, s123, s1234, 4);
T (zero >, s123, s1234, 5);
T (zero >, s123, s1234, SIZE_MAX - 2);
T (zero >, s123, s1234, SIZE_MAX - 1);
T (zero >, s123, s1234, SIZE_MAX);
T (zero ==, s123 + 1, s1234, 0);
T (zero <, s123 + 1, s1234, 1);
T (zero <, s123 + 1, s1234, 2);
T (zero <, s123 + 1, s1234, 3);
T (zero <, s123 + 1, s1234, 4);
T (zero <, s123 + 1, s1234, SIZE_MAX - 2);
T (zero <, s123 + 1, s1234, SIZE_MAX - 1);
T (zero <, s123 + 1, s1234, SIZE_MAX);
T (zero ==, s123 + 1, s1234 + 1, 0);
T (zero ==, s123 + 1, s1234 + 1, 1);
T (zero ==, s123 + 1, s1234 + 1, 2);
T (zero >, s123 + 1, s1234 + 1, 3);
T (zero >, s123 + 1, s1234 + 1, SIZE_MAX - 1);
T (zero >, s123 + 1, s1234 + 1, SIZE_MAX);
T (zero ==, s123 + 3, s1234 + 1, 0);
T (zero >, s123 + 3, s1234 + 1, 1);
T (zero >, s123 + 3, s1234 + 1, 2);
T (zero >, s123 + 3, s1234 + 1, 3);
T (zero >, s123 + 3, s1234 + 1, SIZE_MAX - 1);
T (zero >, s123 + 3, s1234 + 1, SIZE_MAX);
}
/* { dg-final { scan-tree-dump-not "strcmp" "forwprop1" } }
{ dg-final { scan-tree-dump-not "strncmp" "forwprop1" } }
{ dg-final { scan-tree-dump-not "failure_on_line_" "forwprop1" } } */

34
gcc/testsuite/gcc.dg/strcmpopt_9.c Normal file
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/* PR tree-optimization/92683 - strncmp incorrect result with equal substrings
and nonconst bound
{ dg-do run }
{ dg-options "-O2 -Wall" } */
#include "strlenopt.h"
#define ident(n) ident (n)
__attribute__ ((noclone, noinline, noipa)) size_t
ident (size_t x)
{
return x;
}
int nfails;
__attribute__ ((noclone, noinline, noipa)) void
failure_on_line (int line)
{
__builtin_printf ("failure on line %i\n", line);
++nfails;
}
#include "strcmpopt_8.c"
int main (void)
{
test_literal ();
test_cst_array ();
if (nfails)
__builtin_abort ();
}