From: Richard Sandiford <richard.sandiford@arm.com>
Date: Wed, 16 Nov 2016 14:21:32 +0000 (+0000)
Subject: Fix nb_iterations calculation in tree-vect-loop-manip.c
X-Git-Tag: basepoints/gcc-8~3095
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=711188895e4d910aef399ac37084627e003433a8;p=thirdparty%2Fgcc.git

Fix nb_iterations calculation in tree-vect-loop-manip.c

We previously stored the number of loop iterations rather
than the number of latch iterations.

gcc/
2016-11-15  Richard Sandiford  <richard.sandiford@arm.com>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

	* tree-vect-loop-manip.c (slpeel_make_loop_iterate_ntimes): Set
	nb_iterations to the number of latch iterations rather than the
	number of loop iterations.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r242493
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 722b94bff35b..cd59b0280c83 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-11-16  Richard Sandiford  <richard.sandiford@arm.com>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
+	* tree-vect-loop-manip.c (slpeel_make_loop_iterate_ntimes): Set
+	nb_iterations to the number of latch iterations rather than the
+	number of loop iterations.
+
 2016-11-16  Richard Sandiford  <richard.sandiford@arm.com>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index 6bfd332a1019..4c6b8c7459c4 100644
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -285,7 +285,10 @@ slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters)
 		     LOCATION_LINE (loop_loc));
       dump_gimple_stmt (MSG_NOTE, TDF_SLIM, cond_stmt, 0);
     }
-  loop->nb_iterations = niters;
+
+  /* Record the number of latch iterations.  */
+  loop->nb_iterations = fold_build2 (MINUS_EXPR, TREE_TYPE (niters), niters,
+				     build_int_cst (TREE_TYPE (niters), 1));
 }
 
 /* Helper routine of slpeel_tree_duplicate_loop_to_edge_cfg.