[PATCH] Fix PR54981

[Richard Biener]

This fixes PR54981, loop distribution was depending on DEBUG_STMT
uses.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2012-10-19  Richard Guenther  <rguent...@suse.de>

        PR tree-optimization/54981
        * tree-loop-distribution.c (ssa_name_has_uses_outside_loop_p):
        Do not consider debug stmts as uses.

        * gcc.dg/pr54981.c: New testcase.

Index: gcc/tree-loop-distribution.c
===================================================================
*** gcc/tree-loop-distribution.c        (revision 192560)
--- gcc/tree-loop-distribution.c        (working copy)
*************** ssa_name_has_uses_outside_loop_p (tree d
*** 125,132 ****
    use_operand_p use_p;
  
    FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def)
!     if (loop != loop_containing_stmt (USE_STMT (use_p)))
!       return true;
  
    return false;
  }
--- 125,136 ----
    use_operand_p use_p;
  
    FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def)
!     {
!       gimple use_stmt = USE_STMT (use_p);
!       if (!is_gimple_debug (use_stmt)
!         && loop != loop_containing_stmt (use_stmt))
!       return true;
!     }
  
    return false;
  }
Index: gcc/testsuite/gcc.dg/pr54981.c
===================================================================
*** gcc/testsuite/gcc.dg/pr54981.c      (revision 0)
--- gcc/testsuite/gcc.dg/pr54981.c      (working copy)
***************
*** 0 ****
--- 1,15 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O -ftree-loop-distribute-patterns -fcompare-debug" } */
+ 
+ extern void bar(unsigned *, char *);
+ 
+ void foo(char *s)
+ {
+   unsigned i;
+   char t[2];
+ 
+   bar(&i, t);
+ 
+   for (i = 0; i < 2; i++)
+     s[i] = t[i];
+ }