tree-optimization/124132 - fix type problem in loop splitting

The following fixes the computation of the 2nd loop IV bound after
loop splitting when only one of the split IV and the loop control
variable is a pointer.

	PR tree-optimization/124132
	* tree-ssa-loop-split.cc (compute_new_first_bound): Fix
	bound difference computation.

	* gcc.dg/torture/pr124132.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/torture/pr124132.c b/gcc/testsuite/gcc.dg/torture/pr124132.c
new file mode 100644 (file)
index 0000000..8d14fc0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr124132.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-w" } */
+
+char slow_mul1_dst1, code_some_shards___gf_mulc__0, code_some_shards_lim;
+long slow_mul1_dst_max;
+long long code_some_shards_pos;
+void code_some_shards()
+{
+  char *dst = &slow_mul1_dst1;
+  for (; dst < &code_some_shards_lim; dst++)
+    {
+      if (code_some_shards_pos < slow_mul1_dst_max)
+        *dst = code_some_shards___gf_mulc__0;
+      code_some_shards_pos += 1;
+    }
+}

diff --git a/gcc/tree-ssa-loop-split.cc b/gcc/tree-ssa-loop-split.cc
index ba6cc45d7f03c44d79717dc107157daef863e0a6..722383a420acef7699faf1208bc407670ce8c585 100644 (file)
--- a/gcc/tree-ssa-loop-split.cc
+++ b/gcc/tree-ssa-loop-split.cc
@@ -458,21 +458,15 @@ compute_new_first_bound (gimple_seq *stmts, class tree_niter_desc *niter,
   tree end = force_gimple_operand (niter->bound, &stmts2,
                                        true, NULL_TREE);
   gimple_seq_add_seq_without_update (stmts, stmts2);
-  if (POINTER_TYPE_P (TREE_TYPE (enddiff)))
-    {
-      tree tem = gimple_convert (stmts, sizetype, enddiff);
-      tem = gimple_build (stmts, NEGATE_EXPR, sizetype, tem);
-      enddiff = gimple_build (stmts, POINTER_PLUS_EXPR,
-                             TREE_TYPE (enddiff),
-                             end, tem);
-    }
+  if (POINTER_TYPE_P (TREE_TYPE (controlbase)))
+    enddiff = gimple_build (stmts, POINTER_DIFF_EXPR,
+                           ssizetype, end, enddiff);
   else
     enddiff = gimple_build (stmts, MINUS_EXPR, TREE_TYPE (enddiff),
                            end, enddiff);
 
   /* Compute guard_init + (end-beg).  */
   tree newbound;
-  enddiff = gimple_convert (stmts, TREE_TYPE (guard_init), enddiff);
   if (POINTER_TYPE_P (TREE_TYPE (guard_init)))
     {
       enddiff = gimple_convert (stmts, sizetype, enddiff);
@@ -481,8 +475,11 @@ compute_new_first_bound (gimple_seq *stmts, class tree_niter_desc *niter,
                               guard_init, enddiff);
     }
   else
-    newbound = gimple_build (stmts, PLUS_EXPR, TREE_TYPE (guard_init),
-                            guard_init, enddiff);
+    {
+      enddiff = gimple_convert (stmts, TREE_TYPE (guard_init), enddiff);
+      newbound = gimple_build (stmts, PLUS_EXPR, TREE_TYPE (guard_init),
+                              guard_init, enddiff);
+    }
 
   /* Depending on the direction of the IVs the new bound for the first
      loop is the minimum or maximum of old bound and border.