PR tree-optimization/92683 - strncmp incorrect result with equal substrings and non-const bound
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.
===================================================================
@@ -2346,15 +2346,16 @@ gimple_fold_builtin_string_compare (gimple_stmt_it
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. */
@@ -2418,6 +2419,9 @@ gimple_fold_builtin_string_compare (gimple_stmt_it
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. */
===================================================================
@@ -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" } } */
===================================================================
@@ -0,0 +1,34 @@
+/* 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 ();
+}