decl.c (annotate_value): Use test on the sign bit instead of on the sign of the value.

	* gcc-interface/decl.c (annotate_value) <INTEGER_CST>: Use test on
	the sign bit instead of on the sign of the value.
	<PLUS_EXPR>: Turn addition of negative constant into subtraction.
	<MULT_EXPR>: Add test for degenerate case.
	<BIT_AND_EXPR>: Simplify.

From-SVN: r268286

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index d992dc147cf9cad4013f2206cf07c0342852750b..83e651f72688b27b3ee14153ff18e9e6db9608b8 100644 (file)
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,11 @@
+2019-01-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * gcc-interface/decl.c (annotate_value) <INTEGER_CST>: Use test on
+       the sign bit instead of on the sign of the value.
+       <PLUS_EXPR>: Turn addition of negative constant into subtraction.
+       <MULT_EXPR>: Add test for degenerate case.
+       <BIT_AND_EXPR>: Simplify.
+
 2019-01-18  Sebastian Huber  <sebastian.huber@embedded-brains.de>
 
        * s-oscons-tmplt.c (AF_INET6): Do not undefine for RTEMS.

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index 9f2364156892b782d2acb240285126b364c26c78..4a2f6a6177a9a57f889f4bb9f2e9e7cb9afab73a 100644 (file)
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -8250,8 +8250,9 @@ annotate_value (tree gnu_size)
     {
     case INTEGER_CST:
       /* For negative values, build NEGATE_EXPR of the opposite.  Such values
-        can appear for discriminants in expressions for variants.  */
-      if (tree_int_cst_sgn (gnu_size) < 0)
+        can appear for discriminants in expressions for variants.  Note that,
+        sizetype being unsigned, we don't directly use tree_int_cst_sgn.  */
+      if (tree_int_cst_sign_bit (gnu_size))
        {
          tree t = wide_int_to_tree (sizetype, -wi::to_wide (gnu_size));
          tcode = Negate_Expr;
@@ -8323,8 +8324,21 @@ annotate_value (tree gnu_size)
     case EQ_EXPR:              tcode = Eq_Expr; break;
     case NE_EXPR:              tcode = Ne_Expr; break;
 
-    case MULT_EXPR:
     case PLUS_EXPR:
+      /* Turn addition of negative constant into subtraction.  */
+      if (TREE_CODE (TREE_OPERAND (gnu_size, 1)) == INTEGER_CST
+         && tree_int_cst_sign_bit (TREE_OPERAND (gnu_size, 1)))
+       {
+         tcode = Minus_Expr;
+         ops[0] = annotate_value (TREE_OPERAND (gnu_size, 0));
+         wide_int op1 = -wi::to_wide (TREE_OPERAND (gnu_size, 1));
+         ops[1] = annotate_value (wide_int_to_tree (sizetype, op1));
+         break;
+       }
+
+      /* ... fall through ... */
+
+    case MULT_EXPR:
       tcode = (TREE_CODE (gnu_size) == MULT_EXPR ? Mult_Expr : Plus_Expr);
       /* Fold conversions from bytes to bits into inner operations.  */
       if (TREE_CODE (TREE_OPERAND (gnu_size, 1)) == INTEGER_CST
@@ -8334,6 +8348,7 @@ annotate_value (tree gnu_size)
          if (TREE_CODE (inner_op) == TREE_CODE (gnu_size)
              && TREE_CODE (TREE_OPERAND (inner_op, 1)) == INTEGER_CST)
            {
+             ops[0] = annotate_value (TREE_OPERAND (inner_op, 0));
              tree inner_op_op1 = TREE_OPERAND (inner_op, 1);
              tree gnu_size_op1 = TREE_OPERAND (gnu_size, 1);
              widest_int op1;
@@ -8341,10 +8356,13 @@ annotate_value (tree gnu_size)
                op1 = (wi::to_widest (inner_op_op1)
                       * wi::to_widest (gnu_size_op1));
              else
-               op1 = (wi::to_widest (inner_op_op1)
-                      + wi::to_widest (gnu_size_op1));
-             ops[1] = UI_From_gnu (wide_int_to_tree (sizetype, op1));
-             ops[0] = annotate_value (TREE_OPERAND (inner_op, 0));
+               {
+                 op1 = (wi::to_widest (inner_op_op1)
+                        + wi::to_widest (gnu_size_op1));
+                 if (wi::zext (op1, TYPE_PRECISION (sizetype)) == 0)
+                   return ops[0];
+               }
+             ops[1] = annotate_value (wide_int_to_tree (sizetype, op1));
            }
        }
       break;
@@ -8352,18 +8370,12 @@ annotate_value (tree gnu_size)
     case BIT_AND_EXPR:
       tcode = Bit_And_Expr;
       /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
-        Such values appear in expressions with aligning patterns.  Note that,
-        since sizetype is unsigned, we have to jump through some hoops.   */
+        Such values can appear in expressions with aligning patterns.  */
       if (TREE_CODE (TREE_OPERAND (gnu_size, 1)) == INTEGER_CST)
        {
-         tree op1 = TREE_OPERAND (gnu_size, 1);
-         wide_int signed_op1 = wi::sext (wi::to_wide (op1),
-                                         TYPE_PRECISION (sizetype));
-         if (wi::neg_p (signed_op1))
-           {
-             op1 = wide_int_to_tree (sizetype, wi::neg (signed_op1));
-             ops[1] = annotate_value (build1 (NEGATE_EXPR, sizetype, op1));
-           }
+         wide_int op1 = wi::sext (wi::to_wide (TREE_OPERAND (gnu_size, 1)),
+                                  TYPE_PRECISION (sizetype));
+         ops[1] = annotate_value (wide_int_to_tree (sizetype, op1));
        }
       break;