[PATCH] Fix part of PR61383

[Richard Biener]

In comment #3 it's noted that ifcombine happily hoists possibly
trapping stmts ... oops.

Fixed like the following, bootstrap and regtest running on 
x86_64-unknown-linux-gnu.

Richard.

2014-06-02  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/61383
        * tree-ssa-ifcombine.c (bb_no_side_effects_p): Make sure
        stmts can't trap.

        * gcc.dg/torture/pr61383-1.c: New testcase.

Index: gcc/tree-ssa-ifcombine.c
===================================================================
*** gcc/tree-ssa-ifcombine.c    (revision 211125)
--- gcc/tree-ssa-ifcombine.c    (working copy)
*************** bb_no_side_effects_p (basic_block bb)
*** 128,133 ****
--- 128,134 ----
        gimple stmt = gsi_stmt (gsi);
  
        if (gimple_has_side_effects (stmt)
+         || gimple_could_trap_p (stmt)
          || gimple_vuse (stmt))
        return false;
      }
Index: gcc/testsuite/gcc.dg/torture/pr61383-1.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr61383-1.c    (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr61383-1.c    (working copy)
***************
*** 0 ****
--- 1,35 ----
+ /* { dg-do run } */
+ 
+ int a, b = 1, c, d, e, f, g;
+ 
+ int
+ fn1 ()
+ {
+   int h;
+   for (;;)
+     {
+       g = b;
+       g = g ? 0 : 1 % g;
+       e = a + 1;
+       for (; d < 1; d = e)
+       {
+         if (f == 0)
+           h = 0;
+         else
+           h = 1 % f;
+         if (f < 1)
+           c = 0;
+         else if (h)
+           break;
+       }
+       if (b)
+       return 0;
+     }
+ }
+ 
+ int
+ main ()
+ {
+   fn1 ();
+   return 0;
+ }