gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-30.c

   1 /* PR tree-optimization/80933 - redundant bzero/bcopy calls not eliminated
   2    { dg-do compile }
   3    { dg-options "-O2 -fdump-tree-dse1" } */
   4
   5 void sink (void*);
   6
   7 void test_bcopy (const void *s)
   8 {
   9   char d[33];
  10
  11   /* Bcopy is transformed into memmove before DSE runs, so this test
  12      doesn't actually verify that DSE does its job.  */
  13   __builtin_bcopy (s, d, sizeof d);
  14   __builtin_bcopy (s, d, sizeof d);
  15
  16   sink (d);
  17 }
  18
  19 void test_bzero (void)
  20 {
  21   char d[33];
  22
  23   __builtin_bzero (d, sizeof d);
  24   __builtin_bzero (d, sizeof d);
  25
  26   sink (d);
  27 }
  28
  29 /* { dg-final { scan-tree-dump-times "builtin_memset" 1 "dse1" } } */
  30
  31 /* Merging the evrp folder into substitute_and_fold_engine shuffled
  32    the order of gimple_fold a bit, so evrp is no longer folding the
  33    memmove inline.  This folding is instead done by forwprop.  Thus, I
  34    have remmoved the |memmove in the test below as this is not done
  35    until after dse.
  36
  37    What happened was that the propagator engine only called gimple
  38    fold if replace_uses_in() was successful.  On the other hand, EVRP
  39    called gimple fold regardless.
  40
  41    If we really care about previous behavior, we could put a call to
  42    gimple ::fold_stmt into evrp_folder::fold_stmt().  */
  43 /* { dg-final { scan-tree-dump-not "builtin_(bcopy|bzero|memcpy)" "dse1" } } */