[PATCH] Fix PR58539

[Richard Biener]

The vectorizer does not honor the fact that debug statements
do not participate in loop-closed-SSA construction and thus
a SSA name can have outside loop uses that are not in the
loop-closed PHI node but in a debug statement.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2013-09-26  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/58539
	* tree-vect-loop.c (vect_create_epilog_for_reduction): Honor
	the fact that debug statements are not taking part in loop-closed
	SSA construction.

	* gcc.dg/torture/pr58539.c: New testcase.

Index: gcc/tree-vect-loop.c
===================================================================
*** gcc/tree-vect-loop.c	(revision 202883)
--- gcc/tree-vect-loop.c	(working copy)
*************** vect_finalize_reduction:
*** 4411,4417 ****
           result.  (The reduction result is expected to have two immediate uses -
           one at the latch block, and one at the loop exit).  */
        FOR_EACH_IMM_USE_FAST (use_p, imm_iter, scalar_dest)
!         if (!flow_bb_inside_loop_p (loop, gimple_bb (USE_STMT (use_p))))
            phis.safe_push (USE_STMT (use_p));
  
        /* While we expect to have found an exit_phi because of loop-closed-ssa
--- 4411,4418 ----
           result.  (The reduction result is expected to have two immediate uses -
           one at the latch block, and one at the loop exit).  */
        FOR_EACH_IMM_USE_FAST (use_p, imm_iter, scalar_dest)
!         if (!flow_bb_inside_loop_p (loop, gimple_bb (USE_STMT (use_p)))
! 	    && !is_gimple_debug (USE_STMT (use_p)))
            phis.safe_push (USE_STMT (use_p));
  
        /* While we expect to have found an exit_phi because of loop-closed-ssa
*************** vect_finalize_reduction:
*** 4541,4547 ****
        FOR_EACH_IMM_USE_FAST (use_p, imm_iter, scalar_dest)
          {
            if (!flow_bb_inside_loop_p (loop, gimple_bb (USE_STMT (use_p))))
!             phis.safe_push (USE_STMT (use_p));
            else
              {
                if (double_reduc && gimple_code (USE_STMT (use_p)) == GIMPLE_PHI)
--- 4542,4551 ----
        FOR_EACH_IMM_USE_FAST (use_p, imm_iter, scalar_dest)
          {
            if (!flow_bb_inside_loop_p (loop, gimple_bb (USE_STMT (use_p))))
! 	    {
! 	      if (!is_gimple_debug (USE_STMT (use_p)))
! 		phis.safe_push (USE_STMT (use_p));
! 	    }
            else
              {
                if (double_reduc && gimple_code (USE_STMT (use_p)) == GIMPLE_PHI)
*************** vect_finalize_reduction:
*** 4551,4557 ****
                    FOR_EACH_IMM_USE_FAST (phi_use_p, phi_imm_iter, phi_res)
                      {
                        if (!flow_bb_inside_loop_p (loop,
!                                              gimple_bb (USE_STMT (phi_use_p))))
                          phis.safe_push (USE_STMT (phi_use_p));
                      }
                  }
--- 4555,4562 ----
                    FOR_EACH_IMM_USE_FAST (phi_use_p, phi_imm_iter, phi_res)
                      {
                        if (!flow_bb_inside_loop_p (loop,
!                                              gimple_bb (USE_STMT (phi_use_p)))
! 			  && !is_gimple_debug (USE_STMT (phi_use_p)))
                          phis.safe_push (USE_STMT (phi_use_p));
                      }
                  }
Index: gcc/testsuite/gcc.dg/torture/pr58539.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr58539.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr58539.c	(working copy)
***************
*** 0 ****
--- 1,20 ----
+ /* { dg-do compile } */
+ /* { dg-options "-g" } */
+ 
+ int a, b;
+ 
+ extern void baz (int);
+ 
+ int foo (int p)
+ {
+   return p ? p : 1;
+ }
+ 
+ void bar ()
+ {
+   int *c = &a, *d = &a;
+   for (b = 0; b < 12; b++)
+     *d |= 1;
+   foo (*c);
+   baz (*c && 1);
+ }