PR tree-optimization/51246

	* tree-predcom.c (replace_ref_with): Handle also clobber on the
	rhs.

	* gcc.c-torture/compile/pr51246.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@181884 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6a9c965..f82b8bc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2011-12-01  Jakub Jelinek  <jakub@redhat.com>
 
+       PR tree-optimization/51246
+       * tree-predcom.c (replace_ref_with): Handle also clobber on the
+       rhs.
+
        PR rtl-optimization/51014
        * loop-unroll.c (apply_opt_in_copies): Ignore label DEBUG_INSNs
        both from bb and orig_bb.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index acd23f9..7d74e8b 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2011-12-01  Jakub Jelinek  <jakub@redhat.com>
 
+       PR tree-optimization/51246
+       * gcc.c-torture/compile/pr51246.c: New test.
+
        PR rtl-optimization/51014
        * g++.dg/opt/pr51014.C: New test.
 

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr51246.c b/gcc/testsuite/gcc.c-torture/compile/pr51246.c
new file mode 100644 (file)
index 0000000..c206d86
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr51246.c
@@ -0,0 +1,14 @@
+/* PR tree-optimization/51246 */
+
+int a, *b;
+
+void
+test (void)
+{
+  while (1)
+    {
+      int c;
+      a = c;
+      b = &c;
+    }
+}

diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c
index c55c89e..751bdeb 100644 (file)
--- a/gcc/tree-predcom.c
+++ b/gcc/tree-predcom.c
@@ -1306,8 +1306,20 @@ replace_ref_with (gimple stmt, tree new_tree, bool set, bool in_lhs)
       val = gimple_assign_lhs (stmt);
       if (TREE_CODE (val) != SSA_NAME)
        {
-         gcc_assert (gimple_assign_copy_p (stmt));
          val = gimple_assign_rhs1 (stmt);
+         gcc_assert (gimple_assign_single_p (stmt));
+         if (TREE_CLOBBER_P (val))
+           {
+             val = gimple_default_def (cfun, SSA_NAME_VAR (new_tree));
+             if (val == NULL_TREE)
+               {
+                 val = make_ssa_name (SSA_NAME_VAR (new_tree),
+                                      gimple_build_nop ());
+                 set_default_def (SSA_NAME_VAR (new_tree), val);
+               }
+           }
+         else
+           gcc_assert (gimple_assign_copy_p (stmt));
        }
     }
   else