Backported from mainline

	2016-02-16  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/69802
	* tree-ssa-reassoc.c (update_range_test): If op is
	SSA_NAME_IS_DEFAULT_DEF, give up unless tem is a positive
	op == 1 test of precision 1 integral op, otherwise handle
	that case as op itself.  Fix up formatting.
	(optimize_range_tests_to_bit_test, optimize_range_tests): Fix
	up formatting.

	* gcc.dg/pr69802.c: New test.


git-svn-id: https://gcc.gnu.org/svn/gcc/branches/gcc-5-branch@234550 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 72 insertions, 4 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 87c46fe885f..49077d86010 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,14 @@
 	Backported from mainline
 	2016-02-16  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/69802
+	* tree-ssa-reassoc.c (update_range_test): If op is
+	SSA_NAME_IS_DEFAULT_DEF, give up unless tem is a positive
+	op == 1 test of precision 1 integral op, otherwise handle
+	that case as op itself.  Fix up formatting.
+	(optimize_range_tests_to_bit_test, optimize_range_tests): Fix
+	up formatting.
+
 	PR rtl-optimization/69764
 	PR rtl-optimization/69771
 	* optabs.c (expand_binop): Ensure for shift optabs invalid CONST_INT
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 144d040e4e9..b2f70b9d6d8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2016-03-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-02-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/69802
+	* gcc.dg/pr69802.c: New test.
+
 	2016-02-15  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/69797
diff --git a/gcc/testsuite/gcc.dg/pr69802.c b/gcc/testsuite/gcc.dg/pr69802.c
new file mode 100644
index 00000000000..27ee02f36b5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr69802.c
@@ -0,0 +1,23 @@
+/* PR tree-optimization/69802 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+
+struct S { unsigned f : 1; };
+int a, d;
+
+int
+foo (void)
+{
+  unsigned b = 0;
+  struct S c;
+  d = ((1 && b) < c.f) & c.f;	/* { dg-warning "is used uninitialized" } */
+  return a;
+}
+
+int
+bar (_Bool c)
+{
+  unsigned b = 0;
+  d = ((1 && b) < c) & c;
+  return a;
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 03faec5e4b3..0710bae7de0 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -2134,11 +2134,33 @@ update_range_test (struct range_entry *range, struct range_entry *otherrange,
 				in_p, low, high);
   enum warn_strict_overflow_code wc = WARN_STRICT_OVERFLOW_COMPARISON;
   gimple_stmt_iterator gsi;
-  unsigned int i;
+  unsigned int i, uid;
 
   if (tem == NULL_TREE)
     return false;
 
+  /* If op is default def SSA_NAME, there is no place to insert the
+     new comparison.  Give up, unless we can use OP itself as the
+     range test.  */
+  if (op && SSA_NAME_IS_DEFAULT_DEF (op))
+    {
+      if (op == range->exp
+	  && ((TYPE_PRECISION (optype) == 1 && TYPE_UNSIGNED (optype))
+	      || TREE_CODE (optype) == BOOLEAN_TYPE)
+	  && (op == tem
+	      || (TREE_CODE (tem) == EQ_EXPR
+		  && TREE_OPERAND (tem, 0) == op
+		  && integer_onep (TREE_OPERAND (tem, 1))))
+	  && opcode != BIT_IOR_EXPR
+	  && (opcode != ERROR_MARK || oe->rank != BIT_IOR_EXPR))
+	{
+	  stmt = NULL;
+	  tem = op;
+	}
+      else
+	return false;
+    }
+
   if (strict_overflow_p && issue_strict_overflow_warning (wc))
     warning_at (loc, OPT_Wstrict_overflow,
 		"assuming signed overflow does not occur "
@@ -2176,12 +2198,22 @@ update_range_test (struct range_entry *range, struct range_entry *otherrange,
     tem = invert_truthvalue_loc (loc, tem);
 
   tem = fold_convert_loc (loc, optype, tem);
-  gsi = gsi_for_stmt (stmt);
-  unsigned int uid = gimple_uid (stmt);
+  if (stmt)
+    {
+      gsi = gsi_for_stmt (stmt);
+      uid = gimple_uid (stmt);
+    }
+  else
+    {
+      gsi = gsi_none ();
+      uid = 0;
+    }
+  if (stmt == NULL)
+    gcc_checking_assert (tem == op);
   /* In rare cases range->exp can be equal to lhs of stmt.
      In that case we have to insert after the stmt rather then before
      it.  If stmt is a PHI, insert it at the start of the basic block.  */
-  if (op != range->exp)
+  else if (op != range->exp)
     {
       gsi_insert_seq_before (&gsi, seq, GSI_SAME_STMT);
       tem = force_gimple_operand_gsi (&gsi, tem, true, NULL_TREE, true,