gcc/testsuite/gcc.dg/tree-ssa/ssa-thread-invalid.c

   1 // { dg-do compile }
   2 // { dg-options "-O2 -fgimple -fdump-statistics" }
   3 //
   4 // This is a collection of seemingly threadble paths that should not be allowed.
   5
   6 void foobar (int);
   7
   8 // Possible thread from 2->4->3, but it would rotate the loop.
   9 void __GIMPLE (ssa)
  10 f1 ()
  11 {
  12   int i;
  13
  14   // Pre-header.
  15   __BB(2):
  16   goto __BB4;
  17
  18   // Latch.
  19   __BB(3):
  20   foobar (i_1);
  21   i_5 = i_1 + 1;
  22   goto __BB4;
  23
  24   __BB(4,loop_header(1)):
  25   i_1 = __PHI (__BB2: 0, __BB3: i_5);
  26   if (i_1 != 101)
  27     goto __BB3;
  28   else
  29     goto __BB5;
  30
  31   __BB(5):
  32   return;
  33
  34 }
  35
  36 // Possible thread from 2->3->5 but threading through the empty latch
  37 // would create a non-empty latch.
  38 void __GIMPLE (ssa)
  39 f2 ()
  40 {
  41   int i;
  42
  43   // Pre-header.
  44   __BB(2):
  45   goto __BB3;
  46
  47   __BB(3,loop_header(1)):
  48   i_8 = __PHI (__BB5: i_5, __BB2: 0);
  49   foobar (i_8);
  50   i_5 = i_8 + 1;
  51   if (i_5 != 256)
  52     goto __BB5;
  53   else
  54     goto __BB4;
  55
  56   // Latch.
  57   __BB(5):
  58   goto __BB3;
  59
  60   __BB(4):
  61   return;
  62
  63 }
  64
  65 // Possible thread from 3->5->6->3 but this would thread through the
  66 // header but not exit the loop.
  67 int __GIMPLE (ssa)
  68 f3 (int a)
  69 {
  70   int i;
  71
  72   __BB(2):
  73   goto __BB6;
  74
  75   __BB(3):
  76   if (i_1 != 0)
  77     goto __BB4;
  78   else
  79     goto __BB5;
  80
  81   __BB(4):
  82   foobar (5);
  83   goto __BB5;
  84
  85   // Latch.
  86   __BB(5):
  87   i_7 = i_1 + 1;
  88   goto __BB6;
  89
  90   __BB(6,loop_header(1)):
  91   i_1 = __PHI (__BB2: 1, __BB5: i_7);
  92   if (i_1 <= 99)
  93     goto __BB3;
  94   else
  95     goto __BB7;
  96
  97   __BB(7):
  98   return;
  99
 100 }
 101
 102 // { dg-final { scan-tree-dump-not "Jumps threaded" "statistics" } }