re PR tree-optimization/80974 (wrong code (generated code hangs) at -O2 on x86_64...

2017-06-06  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80974
	* tree-ssa-sccvn.c (set_ssa_val_to): Do not change but only
	keep or clear leaders SSA info.

	* gcc.dg/torture/pr80974.c: New testcase.

From-SVN: r248919

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 245ec28096c7108a0f3eae60672fa28b537a1774..38d552433c34dd3964a49b1e4fdd1fc0c3782f85 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-06-06  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/80974
+       * tree-ssa-sccvn.c (set_ssa_val_to): Do not change but only
+       keep or clear leaders SSA info.
+
 2017-06-06  Tom de Vries  <tom@codesourcery.com>
 
        * config/nvptx/nvptx.c (split_mode_p): New function.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8aed9bc4ff2da0a2cbd33b5fceae97fb0a0251a2..a23dc7a184a2ddea8caa08db9b443c14f7b7b8d3 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-06  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/80974
+       * gcc.dg/torture/pr80974.c: New testcase.
+
 2017-06-06  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
        * gcc.dg/utf16-4.c: Accept "long unsigned int" as well as

diff --git a/gcc/testsuite/gcc.dg/torture/pr80974.c b/gcc/testsuite/gcc.dg/torture/pr80974.c
new file mode 100644 (file)
index 0000000..4918607
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr80974.c
@@ -0,0 +1,39 @@
+/* { dg-do run } */
+
+int a, b, c, d, e, f, g[4];
+
+static int fn1 ()
+{
+  int h, i;
+  if (b)
+    goto L1;
+L2:;
+   int m = a;
+   while (1)
+     {
+       int n = 2;
+       e = !f && (n = 5);
+       if (e)
+        for (h = 0; h < 9; h++)
+          for (i = 0; i < 6; i++)
+            if (a)
+              g[h] = 4;
+       if (d)
+        goto L2;
+       a & n || b;
+L1:
+       if (a)
+        L3:
+            c = m;
+       if (a)
+        goto L3;
+       if (b < 5)
+        return 0;
+     }
+}
+
+int main ()
+{
+  fn1 ();
+  return 0; 
+}

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index c140c358fc31c9d9f01cdd02372780059e04a10e..ff5c800662b284994c35453c7cf8007b689d53f3 100644 (file)
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -3328,6 +3328,9 @@ set_ssa_val_to (tree from, tree to)
               == get_addr_base_and_unit_offset (TREE_OPERAND (to, 0), &toff))
           && coff == toff))
     {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, " (changed)\n");
+
       /* If we equate two SSA names we have to make the side-band info
          of the leader conservative (and remember whatever original value
         was present).  */
@@ -3342,22 +3345,6 @@ set_ssa_val_to (tree from, tree to)
                         gimple_bb (SSA_NAME_DEF_STMT (to))))
                /* Keep the info from the dominator.  */
                ;
-             else if (SSA_NAME_IS_DEFAULT_DEF (from)
-                      || dominated_by_p_w_unex
-                           (gimple_bb (SSA_NAME_DEF_STMT (to)),
-                            gimple_bb (SSA_NAME_DEF_STMT (from))))
-               {
-                 /* Save old info.  */
-                 if (! VN_INFO (to)->info.range_info)
-                   {
-                     VN_INFO (to)->info.range_info = SSA_NAME_RANGE_INFO (to);
-                     VN_INFO (to)->range_info_anti_range_p
-                       = SSA_NAME_ANTI_RANGE_P (to);
-                   }
-                 /* Use that from the dominator.  */
-                 SSA_NAME_RANGE_INFO (to) = SSA_NAME_RANGE_INFO (from);
-                 SSA_NAME_ANTI_RANGE_P (to) = SSA_NAME_ANTI_RANGE_P (from);
-               }
              else
                {
                  /* Save old info.  */
@@ -3369,6 +3356,12 @@ set_ssa_val_to (tree from, tree to)
                    }
                  /* Rather than allocating memory and unioning the info
                     just clear it.  */
+                 if (dump_file && (dump_flags & TDF_DETAILS))
+                   {
+                     fprintf (dump_file, "clearing range info of ");
+                     print_generic_expr (dump_file, to);
+                     fprintf (dump_file, "\n");
+                   }
                  SSA_NAME_RANGE_INFO (to) = NULL;
                }
            }
@@ -3381,17 +3374,6 @@ set_ssa_val_to (tree from, tree to)
                         gimple_bb (SSA_NAME_DEF_STMT (to))))
                /* Keep the info from the dominator.  */
                ;
-             else if (SSA_NAME_IS_DEFAULT_DEF (from)
-                      || dominated_by_p_w_unex
-                           (gimple_bb (SSA_NAME_DEF_STMT (to)),
-                            gimple_bb (SSA_NAME_DEF_STMT (from))))
-               {
-                 /* Save old info.  */
-                 if (! VN_INFO (to)->info.ptr_info)
-                   VN_INFO (to)->info.ptr_info = SSA_NAME_PTR_INFO (to);
-                 /* Use that from the dominator.  */
-                 SSA_NAME_PTR_INFO (to) = SSA_NAME_PTR_INFO (from);
-               }
              else if (! SSA_NAME_PTR_INFO (from)
                       /* Handle the case of trivially equivalent info.  */
                       || memcmp (SSA_NAME_PTR_INFO (to),
@@ -3403,14 +3385,18 @@ set_ssa_val_to (tree from, tree to)
                    VN_INFO (to)->info.ptr_info = SSA_NAME_PTR_INFO (to);
                  /* Rather than allocating memory and unioning the info
                     just clear it.  */
+                 if (dump_file && (dump_flags & TDF_DETAILS))
+                   {
+                     fprintf (dump_file, "clearing points-to info of ");
+                     print_generic_expr (dump_file, to);
+                     fprintf (dump_file, "\n");
+                   }
                  SSA_NAME_PTR_INFO (to) = NULL;
                }
            }
        }
 
       VN_INFO (from)->valnum = to;
-      if (dump_file && (dump_flags & TDF_DETAILS))
-       fprintf (dump_file, " (changed)\n");
       return true;
     }
   if (dump_file && (dump_flags & TDF_DETAILS))