Skip properly debug stmt in optimize_mask_stores (PR

	PR tree-optimization/70043
	* tree-vect-loop.c (optimize_mask_stores): Move iterator to
	previous statement if we see a debug statement.
	* gfortran.dg/vect/pr70043.f90: New test.

From-SVN: r233934

gcc/ChangeLog

+2016-03-03  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/70043
+	* tree-vect-loop.c (optimize_mask_stores): Move iterator to
+	previous statement if we see a debug statement.
+
 2016-03-03  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/55936

gcc/testsuite/ChangeLog

+2016-03-03  Ilya Enkovich  <enkovich.gnu@gmail.com>
+
+	PR tree-optimization/70043
+	* gfortran.dg/vect/pr70043.f90: New test.
+
 2016-03-03  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/specs/task1.ads: New test.

gcc/testsuite/gfortran.dg/vect/pr70043.f90

+! { dg-do compile  }
+! { dg-additional-options "-Ofast -g" }
+! { dg-additional-options "-march=haswell" { target i?86-*-* x86_64-*-* } }
+
+subroutine fn1(a, b)
+  real(8), intent(in) ::  b(100)
+  real(8), intent(inout) :: a(100)
+  real(8) c
+  do i=0,100
+     if( a(i) < 0.0 ) then
+        c =  a(i) * b(i)
+        a(i) = a(i) - c / b(i)
+     endif
+  enddo
+end subroutine fn1

gcc/tree-vect-loop.c

@@ -7090,7 +7090,10 @@ optimize_mask_stores (struct loop *loop)
 
 	      /* Skip debug statements.  */
 	      if (is_gimple_debug (gsi_stmt (gsi)))
-		continue;
+		{
+		  gsi_prev (&gsi);
+		  continue;
+		}
 	      stmt1 = gsi_stmt (gsi);
 	      /* Do not consider statements writing to memory or having
 		 volatile operand.  */