tree-ssa-loop-ivopts.c (set_autoinc_for_original_candidates): Find au…

…to-increment use both before and after candidate.

	* tree-ssa-loop-ivopts.c (set_autoinc_for_original_candidates):
	Find auto-increment use both before and after candidate.

	* gcc.target/arm/ivopts-orig_biv-inc.c: New testcase.

From-SVN: r202164

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2013-09-02  Bin Cheng  <[email protected]>
+
+	* tree-ssa-loop-ivopts.c (set_autoinc_for_original_candidates):
+	Find auto-increment use both before and after candidate.
+
 2013-09-02  Marek Polacek  <[email protected]>
 
 	* Makefile.in (ubsan.o): Add $(TM_P_H) dependency.

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2013-09-02  Bin Cheng  <[email protected]>
+
+	* gcc.target/arm/ivopts-orig_biv-inc.c: New testcase.
+
 2013-09-02  Paolo Carlini  <[email protected]>
 
 	PR c++/21682, implement DR 565

gcc/testsuite/gcc.target/arm/ivopts-orig_biv-inc.c

@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-ivopts-details" } */
+/* { dg-skip-if "" { arm_thumb1 } } */
+
+extern char *__ctype_ptr__;
+
+unsigned char * foo(unsigned char *ReadPtr)
+{
+
+ unsigned char c;
+
+ while (!(((__ctype_ptr__+sizeof(""[*ReadPtr]))[(int)(*ReadPtr)])&04) == (!(0)))
+  ReadPtr++;
+
+ return ReadPtr;
+}
+
+/* { dg-final { scan-tree-dump-times "original biv" 2 "ivopts"} } */
+/* { dg-final { cleanup-tree-dump "ivopts" } } */

gcc/tree-ssa-loop-ivopts.c

@@ -4876,22 +4876,36 @@ set_autoinc_for_original_candidates (struct ivopts_data *data)
   for (i = 0; i < n_iv_cands (data); i++)
     {
       struct iv_cand *cand = iv_cand (data, i);
-      struct iv_use *closest = NULL;
+      struct iv_use *closest_before = NULL;
+      struct iv_use *closest_after = NULL;
       if (cand->pos != IP_ORIGINAL)
 	continue;
+
       for (j = 0; j < n_iv_uses (data); j++)
 	{
 	  struct iv_use *use = iv_use (data, j);
 	  unsigned uid = gimple_uid (use->stmt);
-	  if (gimple_bb (use->stmt) != gimple_bb (cand->incremented_at)
-	      || uid > gimple_uid (cand->incremented_at))
+
+	  if (gimple_bb (use->stmt) != gimple_bb (cand->incremented_at))
 	    continue;
-	  if (closest == NULL || uid > gimple_uid (closest->stmt))
-	    closest = use;
+
+	  if (uid < gimple_uid (cand->incremented_at)
+	      && (closest_before == NULL
+		  || uid > gimple_uid (closest_before->stmt)))
+	    closest_before = use;
+
+	  if (uid > gimple_uid (cand->incremented_at)
+	      && (closest_after == NULL
+		  || uid < gimple_uid (closest_after->stmt)))
+	    closest_after = use;
 	}
-      if (closest == NULL || !autoinc_possible_for_pair (data, closest, cand))
-	continue;
-      cand->ainc_use = closest;
+
+      if (closest_before != NULL
+	  && autoinc_possible_for_pair (data, closest_before, cand))
+	cand->ainc_use = closest_before;
+      else if (closest_after != NULL
+	       && autoinc_possible_for_pair (data, closest_after, cand))
+	cand->ainc_use = closest_after;
     }
 }