PR tree-optimization/86415 - strlen() not folded for substrings within constant arrays

gcc/testsuite/ChangeLog:

	* gcc.dg/strlenopt-53.c: New test.

From-SVN: r262528

gcc/testsuite/ChangeLog

 2018-07-09  Martin Sebor  <msebor@redhat.com>
 
+	PR tree-optimization/86415
+	* gcc.dg/strlenopt-53.c: New test.
+
+2018-07-09  Martin Sebor  <msebor@redhat.com>
+
 	PR middle-end/77357
 	* gcc.dg/strlenopt-49.c: New test.
 	* gcc.dg/strlenopt-50.c: New test.

gcc/testsuite/gcc.dg/strlenopt-53.c

+/* PR tree-optimization/86415 - strlen() not folded for substrings
+   within constant arrays
+   { dg-do compile }
+   { dg-options "-O2 -Wall -fdump-tree-gimple -fdump-tree-ccp" } */
+
+#include "strlenopt.h"
+
+#define CONCAT(x, y) x ## y
+#define CAT(x, y) CONCAT (x, y)
+#define FAILNAME(name) CAT (call_ ## name ##_on_line_, __LINE__)
+
+#define FAIL(name) do {				\
+    extern void FAILNAME (name) (void);		\
+    FAILNAME (name)();				\
+  } while (0)
+
+/* Macro to emit a call to funcation named
+   call_in_true_branch_not_eliminated_on_line_NNN()
+   for each call that's expected to be eliminated.  The dg-final
+   scan-tree-dump-time directive at the bottom of the test verifies
+   that no such call appears in output.  */
+#define ELIM(expr)							\
+  if (!(expr)) FAIL (in_true_branch_not_eliminated); else (void)0
+
+#define T(s, n) ELIM (strlen (s) == n)
+
+/*                              11111
+				0 1  23 4  567 8  901234  */
+#define STR "1\00012\000123\0001234\0"
+
+const char a[]   = STR;
+const char b[20] = STR;
+
+void test_literal (void)
+{
+  /* Verify that strlen() of substrings within a string literal are
+     correctly folded.  */
+  T (STR,      1);  T (STR +  1, 0);  T (STR +  2, 2);  T (STR +  3, 1);
+  T (STR +  4, 0);  T (STR +  5, 3);  T (STR +  6, 2);  T (STR +  7, 1);
+  T (STR +  8, 0);  T (STR +  9, 4);  T (STR + 10, 3);  T (STR + 11, 2);
+  T (STR + 12, 1);  T (STR + 13, 0);  T (STR + 14, 0);
+
+  T (&(STR[0]),  1);  T (&(STR[ 1]), 0);  T (&(STR[ 2]), 2);
+  T (&(STR[ 3]), 1);  T (&(STR[ 4]), 0);  T (&(STR[ 5]), 3);
+  T (&(STR[ 6]), 2);  T (&(STR[ 7]), 1);  T (&(STR[ 8]), 0);
+  T (&(STR[ 9]), 4);  T (&(STR[10]), 3);  T (&(STR[11]), 2);
+  T (&(STR[12]), 1);  T (&(STR[13]), 0);  T (&(STR[14]), 0);
+
+  T (&(STR[0])  +  1, 0);  T (&(STR[ 1]) +  1, 2);  T (&(STR[ 2]) +  1, 1);
+  T (&(STR[ 3]) +  1, 0);  T (&(STR[ 4]) +  1, 3);  T (&(STR[ 5]) +  1, 2);
+  T (&(STR[ 6]) +  1, 1);  T (&(STR[ 7]) +  1, 0);  T (&(STR[ 8]) +  1, 4);
+  T (&(STR[ 9]) +  1, 3);  T (&(STR[10]) +  1, 2);  T (&(STR[11]) +  1, 1);
+  T (&(STR[12]) +  1, 0);  T (&(STR[13]) +  1, 0);  T (&(STR[13]) - 13, 1);
+  T (&(STR[13]) - 12, 0);  T (&(STR[13]) - 11, 2);  T (&(STR[13]) - 10, 1);
+}
+
+void test_array (void)
+{
+  /* Verify that strlen() of substrings within a fully initialized
+     array are correctly folded.  */
+  T (a,      1);  T (a +  1, 0);  T (a +  2, 2);  T (a +  3, 1);
+  T (a +  4, 0);  T (a +  5, 3);  T (a +  6, 2);  T (a +  7, 1);
+  T (a +  8, 0);  T (a +  9, 4);  T (a + 10, 3);  T (a + 11, 2);
+  T (a + 12, 1);  T (a + 13, 0);  T (a + 14, 0);
+
+  /* Verify that strlen() of substrings within a partially initialized
+     array are also correctly folded, including those referring to
+     the empty substrings in the implicitly initialized elements.  */
+  T (b,      1);  T (b +  1, 0);  T (b +  2, 2);  T (b +  3, 1);
+  T (b +  4, 0);  T (b +  5, 3);  T (b +  6, 2);  T (b +  7, 1);
+  T (b +  8, 0);  T (b +  9, 4);  T (b + 10, 3);  T (b + 11, 2);
+  T (b + 12, 1);  T (b + 13, 0);  T (b + 14, 0);  T (b + 15, 0);
+  T (b + 16, 0);  T (b + 17, 0);  T (b + 18, 0);  T (b + 19, 0);
+}
+
+void test_array_ref_plus (void)
+{
+  /* Verify that strlen() of substrings within a fully initialized
+     array referred to by array indices with offsets are correctly
+     folded.  */
+  T (&a[ 0],     1);  T (&a[ 0] + 1, 0);
+  T (&a[ 1],     0);  T (&a[ 1] + 1, 2);
+  T (&a[ 2],     2);  T (&a[ 2] + 1, 1);  T (&a[ 2] + 2, 0);
+  T (&a[ 3],     1);  T (&a[ 3] + 1, 0);
+  T (&a[ 4],     0);  T (&a[ 4] + 1, 3);
+  T (&a[ 5],     3);  T (&a[ 5] + 1, 2);
+  T (&a[ 5] + 2, 1);  T (&a[ 5] + 3, 0);  T (&a[ 5] + 4, 4);
+  T (&a[ 6],     2);  T (&a[ 6] + 1, 1);  T (&a[ 6] + 2, 0);
+  T (&a[ 7],     1);  T (&a[ 7] + 1, 0);
+  T (&a[ 8],     0);  T (&a[ 8] + 1, 4);
+  T (&a[ 9],     4);  T (&a[ 9] + 1, 3);  T (&a[ 9] + 2, 2);
+  T (&a[ 9] + 3, 1);  T (&a[ 9] + 4, 0);  T (&a[ 9] + 5, 0);
+  T (&a[10],     3);  T (&a[10] + 1, 2);  T (&a[10] + 2, 1);
+  T (&a[10] + 3, 0);  T (&a[10] + 4, 0);
+  T (&a[11],     2);  T (&a[11] + 1, 1);  T (&a[11] + 2, 0);
+  T (&a[12],     1);  T (&a[12] + 1, 0);  T (&a[12] + 2, 0);
+  T (&a[13],     0);  T (&a[13] + 1, 0);
+  T (&a[14],     0);
+}
+
+void test_array_ref (void)
+{
+  T (&a[ 0], 1);  T (&a[ 1], 0);  T (&a[ 2], 2);  T (&a[ 3], 1);
+  T (&a[ 4], 0);  T (&a[ 5], 3);  T (&a[ 6], 2);  T (&a[ 7], 1);
+  T (&a[ 8], 0);  T (&a[ 9], 4);  T (&a[10], 3);  T (&a[11], 2);
+  T (&a[12], 1);  T (&a[13], 0);  T (&a[14], 0);
+
+  T (&b[ 0], 1);  T (&b[ 1], 0);  T (&b[ 2], 2);  T (&b[ 3], 1);
+  T (&b[ 4], 0);  T (&b[ 5], 3);  T (&b[ 6], 2);  T (&b[ 7], 1);
+  T (&b[ 8], 0);  T (&b[ 9], 4);  T (&b[10], 3);  T (&b[11], 2);
+  T (&b[12], 1);  T (&b[13], 0);  T (&b[14], 0);  T (&b[15], 0);
+  T (&b[16], 0);  T (&b[17], 0);  T (&b[18], 0);  T (&b[19], 0);
+}
+
+/* { dg-final { scan-tree-dump-times "strlen" 0 "gimple" } }
+   { dg-final { scan-tree-dump-times "call_in_true_branch_not_eliminated" 0 "ccp1" } } */