gcc/testsuite/gcc.dg/strlenopt-89.c

/* PR tree-optimization/92226 - live nul char store to array eliminated
   { dg-do compile }
   { dg-options "-O2 -fdump-tree-strlen" } */

#include "strlenopt.h"

#define NOIPA __attribute__ ((noipa))

/* Verify that the nul store  into the destination is only eliminated
   when overwrites the existing terminating nul added by the strcpy call.
   Also verify that the second strlen call is eliminated in all cases.  */
#define T(SIZE, IDX)							\
  NOIPA void test_ ## SIZE ## _store_nul_ ## IDX (const char *s)	\
  {									\
    extern char a ## SIZE[SIZE];					\
    char *d = a ## SIZE;						\
    size_t len = SIZE - 1;						\
    size_t idx = IDX;							\
    if (strlen (s) == len)						\
      {									\
	strcpy (d, s);							\
	d[idx] = 0;							\
	if (strlen (d) != idx)						\
	  abort ();							\
      }									\
  } typedef void dummy_type


T (1, 0);   // expect nul store to be eliminated

T (2, 0);   // nul store must be retained
T (2, 1);   // expect nul store to be eliminated

// Same as above but for larger arrays.
T (3, 0);
T (3, 1);
T (3, 2);

T (4, 0);
T (4, 1);
T (4, 2);
T (4, 3);

T (5, 0);
T (5, 1);
T (5, 2);
T (5, 3);
T (5, 4);

T (6, 0);
T (6, 1);
T (6, 2);
T (6, 3);
T (6, 4);
T (6, 5);

T (7, 0);
T (7, 1);
T (7, 2);
T (7, 3);
T (7, 4);
T (7, 5);
T (7, 6);

T (8, 0);
T (8, 1);
T (8, 2);
T (8, 3);
T (8, 4);
T (8, 5);
T (8, 6);
T (8, 7);

/* Verify that each function makes just one call to strlen to compute
   the length of its argument (and not also to compute the length of
   the copy):
  { dg-final { scan-tree-dump-times "strlen \\(s_" 36 "strlen1" } }
  { dg-final { scan-tree-dump-not "strlen \\(\\&a" "strlen1" } }

  Verify that nul stores into the last array element have been eliminated
  (they are preceded by a strcpy storing into all the elements of the array:
  { dg-final { scan-tree-dump-not "a1\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a2 \\\+ 1B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a3 \\\+ 2B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a4 \\\+ 3B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a5 \\\+ 4B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a6 \\\+ 5B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a7 \\\+ 6B\\\] = 0;" "strlen1" } }
  { dg-final { scan-tree-dump-not "a8 \\\+ 7B\\\] = 0;" "strlen1" } } */