opt77.adb: New test.

	* gnat.dg/opt77.adb: New test.
	* gnat.dg/opt77_pkg.ad[sb]: New helper.

From-SVN: r269208

1 files changed, 24 insertions, 6 deletions

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 12647e7..4f4b7db 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -170,11 +170,10 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
   gimple *def_stmt = SSA_NAME_DEF_STMT (name);
   if (is_gimple_assign (def_stmt))
     {
-      /* We know the result of DEF_STMT was zero.  See if that allows
-	 us to deduce anything about the SSA_NAMEs used on the RHS.  */
       enum tree_code code = gimple_assign_rhs_code (def_stmt);
       switch (code)
 	{
+	/* If the result of an OR is zero, then its operands are, too.  */
 	case BIT_IOR_EXPR:
 	  if (integer_zerop (value))
 	    {
@@ -188,8 +187,7 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
 	    }
 	  break;
 
-      /* We know the result of DEF_STMT was one.  See if that allows
-	 us to deduce anything about the SSA_NAMEs used on the RHS.  */
+	/* If the result of an AND is nonzero, then its operands are, too.  */
 	case BIT_AND_EXPR:
 	  if (!integer_zerop (value))
 	    {
@@ -296,7 +294,6 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
 	    break;
 	  }
 
-
 	case EQ_EXPR:
 	case NE_EXPR:
 	  {
@@ -336,7 +333,28 @@ edge_info::derive_equivalences (tree name, tree value, int recursion_limit)
 	case NEGATE_EXPR:
 	  {
 	    tree rhs = gimple_assign_rhs1 (def_stmt);
-	    tree res = fold_build1 (code, TREE_TYPE (rhs), value);
+	    tree res;
+	    /* If this is a NOT and the operand has a boolean range, then we
+	       know its value must be zero or one.  We are not supposed to
+	       have a BIT_NOT_EXPR for boolean types with precision > 1 in
+	       the general case, see e.g. the handling of TRUTH_NOT_EXPR in
+	       the gimplifier, but it can be generated by match.pd out of
+	       a BIT_XOR_EXPR wrapped in a BIT_AND_EXPR.  Now the handling
+	       of BIT_AND_EXPR above already forces a specific semantics for
+	       boolean types with precision > 1 so we must do the same here,
+	       otherwise we could change the semantics of TRUTH_NOT_EXPR for
+	       boolean types with precision > 1.  */
+	    if (code == BIT_NOT_EXPR
+		&& TREE_CODE (rhs) == SSA_NAME
+		&& ssa_name_has_boolean_range (rhs))
+	      {
+		if (integer_zerop (value))
+		  res = build_one_cst (TREE_TYPE (rhs));
+		else
+		  res = build_zero_cst (TREE_TYPE (rhs));
+	      }
+	    else
+	      res = fold_build1 (code, TREE_TYPE (rhs), value);
 	    derive_equivalences (rhs, res, recursion_limit - 1);
 	    break;
 	  }