opt77.adb: New test.

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

From-SVN: r269208

gcc/ChangeLog

+2019-02-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* tree-ssa-dom.c (edge_info::derive_equivalences) <BIT_IOR_EXPR>: Fix
+	and move around comment.
+	<BIT_AND_EXPR>: Likewise.
+	<BIT_NOT_EXPR>: Add specific handling for boolean types.
+
 2019-02-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/89474

gcc/testsuite/ChangeLog

+2019-02-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/opt77.adb: New test.
+	* gnat.dg/opt77_pkg.ad[sb]: New helper.
+
 2019-02-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/89474

gcc/testsuite/gnat.dg/opt77.adb

+-- { dg-do run }
+-- { dg-options "-O -fno-inline" }
+
+with Opt77_Pkg; use Opt77_Pkg;
+
+procedure Opt77 is
+  N : Natural := 0;
+  To_Add : Boolean;
+begin
+  Proc ("One", N, To_Add);
+  if To_Add then
+    raise Program_Error;
+  end if;
+end;

gcc/testsuite/gnat.dg/opt77_pkg.adb

+package body Opt77_Pkg is
+
+  function Compare (S : String) return Boolean is
+  begin
+    return S = "Two";
+  end;
+
+  procedure Proc (S : String; N : in out Natural; To_Add : out Boolean) is
+    To_Take : Boolean := False;
+    To_Read : Boolean := False;
+  begin
+    To_Add := False;
+
+    if S = "One" then
+      To_Read := True;
+      To_Take := Compare (S);
+    end if;
+
+    if To_Read and not To_Take then
+      N := N + 1;
+    end if;
+
+    if To_Take then
+      To_Add := True;
+    end if;
+  end;
+
+end Opt77_Pkg;

gcc/testsuite/gnat.dg/opt77_pkg.ads

+package Opt77_Pkg is
+
+  procedure Proc (S : String; N : in out Natural; To_Add : out Boolean);
+
+end Opt77_Pkg;

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;
 	  }