tree-ssa-threadedge.c (simplify_control_stmt_condition): Look deeper into the SSA_NAME_VALUE chain.

	tree-optimization/61607
	* tree-ssa-threadedge.c (simplify_control_stmt_condition): Look
	deeper into the SSA_NAME_VALUE chain.

	tree-optimization/61607
	* gcc.dg/tree-ssa/pr61607.c: New test.

From-SVN: r212149

4 files changed, 67 insertions, 10 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 70f8088..61df10d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2014-06-30  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/61607
+	* tree-ssa-threadedge.c (simplify_control_stmt_condition): Look
+	deeper into the SSA_NAME_VALUE chain.
+
 2014-06-30  Marek Polacek  <polacek@redhat.com>
 
 	* convert.c (convert_to_integer): Don't instrument conversions if the
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4191a97..4c4b683 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-06-30  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/61607
+	* gcc.dg/tree-ssa/pr61607.c: New test.
+
 2014-06-30  Marek Polacek  <polacek@redhat.com>
 
 	* c-c++-common/ubsan/attrib-2.c: New test.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr61607.c b/gcc/testsuite/gcc.dg/tree-ssa/pr61607.c
new file mode 100644
index 0000000..924d686
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr61607.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -fno-tree-fre -fdump-tree-dom1" } */
+
+void foo(int *);
+void f2(int dst[3], int R)
+{
+  int i, inter[2];
+  _Bool inter0p = 0;
+  _Bool inter1p = 0;
+  for (i = 1; i < R; i++)
+    {
+      inter0p = 1;
+      inter1p = 1;
+    }
+  if (inter0p)
+    inter[0] = 1;
+  if (inter1p)
+    inter[1] = 1;
+  foo(inter);
+}
+
+
+/* There should be precisely two conditionals.  One for the loop condition
+   and one for the test after the loop.  Previously we failed to eliminate
+   the second conditional after the loop.  */
+/* { dg-final { scan-tree-dump-times "if" 2 "dom1"} } */
+
+/* { dg-final { cleanup-tree-dump "dom1" } } */
+
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index a76a7ce..9807b42 100644
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -542,16 +542,26 @@ simplify_control_stmt_condition (edge e,
       /* Get the current value of both operands.  */
       if (TREE_CODE (op0) == SSA_NAME)
 	{
-          tree tmp = SSA_NAME_VALUE (op0);
-	  if (tmp)
-	    op0 = tmp;
+	  for (int i = 0; i < 2; i++)
+	    {
+	      if (TREE_CODE (op0) == SSA_NAME
+		  && SSA_NAME_VALUE (op0))
+		op0 = SSA_NAME_VALUE (op0);
+	      else
+		break;
+	    }
 	}
 
       if (TREE_CODE (op1) == SSA_NAME)
 	{
-	  tree tmp = SSA_NAME_VALUE (op1);
-	  if (tmp)
-	    op1 = tmp;
+	  for (int i = 0; i < 2; i++)
+	    {
+	      if (TREE_CODE (op1) == SSA_NAME
+		  && SSA_NAME_VALUE (op1))
+		op1 = SSA_NAME_VALUE (op1);
+	      else
+		break;
+	    }
 	}
 
       if (handle_dominating_asserts)
@@ -625,10 +635,17 @@ simplify_control_stmt_condition (edge e,
 	 It is possible to get loops in the SSA_NAME_VALUE chains
 	 (consider threading the backedge of a loop where we have
 	 a loop invariant SSA_NAME used in the condition.  */
-      if (cached_lhs
-	  && TREE_CODE (cached_lhs) == SSA_NAME
-	  && SSA_NAME_VALUE (cached_lhs))
-	cached_lhs = SSA_NAME_VALUE (cached_lhs);
+      if (cached_lhs)
+	{
+	  for (int i = 0; i < 2; i++)
+	    {
+	      if (TREE_CODE (cached_lhs) == SSA_NAME
+		  && SSA_NAME_VALUE (cached_lhs))
+		cached_lhs = SSA_NAME_VALUE (cached_lhs);
+	      else
+		break;
+	    }
+	}
 
       /* If we're dominated by a suitable ASSERT_EXPR, then
 	 update CACHED_LHS appropriately.  */