gcc/testsuite/gcc.dg/strlenopt-72.c

/* PR tree-optimization/91183 - strlen of a strcpy result with a conditional
   source not folded
   Test to verify that strlen can determine string lengths from wider stores
   than narrow characters.  This matters because on targets that can handle
   unaligned stores and where GCC lowers multi-character stores into smaller
   numbers of wider stores.
   { dg-do compile }
   { dg-options "-O2 -fdump-tree-optimized" }
   On strictly aligned targets the consecutive char assignments used
   by the test aren't merged.  When they involve multiple trailing nuls
   these assignments then defeat the strlen optimization as a result of
   pr83821.  When the bug is resolved the directive below can be removed.
   { dg-require-effective-target non_strict_align } */

#include "strlenopt.h"

#define CAT(x, y) x ## y
#define CONCAT(x, y) CAT (x, y)
#define FAILNAME(name) CONCAT (call_ ## name ##_on_line_, __LINE__)

#define FAIL(name) do {				\
    extern void FAILNAME (name) (void);		\
    FAILNAME (name)();				\
  } while (0)

/* Macros to emit a call to function named
     call_failed_to_be_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 (not_eliminated); else (void)0

#undef T
#define T(N, ncpy, expect, assign) do {				\
    char a[N], b[N];						\
    assign;							\
    memcpy (b, a, ncpy);					\
    ELIM (!(expect == strlen (b)));				\
  } while (0)

void test_copy (void)
{
  T (2, 1, 0, (a[0] = 0));
  T (2, 2, 0, (a[0] = 0, a[1] = 0));
  T (2, 2, 1, (a[0] = '1', a[1] = 0));
  T (4, 3, 2, (a[0] = '1', a[1] = '2', a[2] = 0));
  // Not handled due to pr83821:
  // T (4, 3, 1, (a[0] = '1', a[1] = 0, a[2] = '2'));
  T (4, 2, 1, (a[0] = '1', a[1] = 0,   a[2] = 0,   a[3] = 0));
  // Not handled due to pr83821:
  // T (4, 3, 1, (a[0] = '1', a[1] = 0,   a[2] = 0,   a[3] = 0));
  T (4, 4, 1, (a[0] = '1', a[1] = 0,   a[2] = 0,   a[3] = 0));
  T (4, 3, 2, (a[0] = '1', a[1] = '2', a[2] = 0,   a[3] = 0));
  T (4, 4, 2, (a[0] = '1', a[1] = '2', a[2] = 0,   a[3] = 0));
  T (4, 4, 3, (a[0] = '1', a[1] = '2', a[2] = '3', a[3] = 0));
  T (5, 4, 1, (a[0] = '1', a[1] = 0,   a[2] = 0,   a[3] = 0));
  T (5, 4, 2, (a[0] = '1', a[1] = '2', a[2] = 0,   a[3] = 0));
  T (5, 4, 3, (a[0] = '1', a[1] = '2', a[2] = '3', a[3] = 0));
  // Not handled:
  // T (5, 5, 1, (a[0] = '1', a[1] = 0,   a[2] = 0,   a[3] = 0,   a[4] = 0));
  // T (5, 5, 2, (a[0] = '1', a[1] = '2', a[2] = 0,   a[3] = 0,   a[4] = 0));
  // T (5, 5, 3, (a[0] = '1', a[1] = '2', a[2] = '3', a[3] = 0,   a[4] = 0));
  T (5, 5, 4, (a[0] = '1', a[1] = '2', a[2] = '3', a[3] = '4', a[4] = 0));
}


/* { dg-final { scan-tree-dump-times "strlen" 0 "optimized" } }
   { dg-final { scan-tree-dump-times "_not_eliminated_" 0 "optimized" } } */