From: Eric Botcazou <ebotcazou@adacore.com>
Date: Sat, 26 Jan 2019 11:36:05 +0000 (+0000)
Subject: decl.c (annotate_value): Use test on the sign bit instead of on the sign of the value.
X-Git-Tag: releases/gcc-7.5.0~640
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=720a687a9b68bfcb600cae58c20fb4d7794b6d15;p=thirdparty%2Fgcc.git

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.
	<BIT_AND_EXPR>: Simplify.

From-SVN: r268288
---

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index ca2802672207..f8f948b8dce5 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+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.
+	<BIT_AND_EXPR>: Simplify.
+
 2018-12-24  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* adaint.c [__APPLE__] (__gnat_lwp_self): Ensure that the system
diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index 5bd76ef54bf6..bf3269af5345 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -8078,8 +8078,9 @@ 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::neg (gnu_size));
 	  return annotate_value (build1 (NEGATE_EXPR, sizetype, t));
@@ -8111,7 +8112,6 @@ annotate_value (tree gnu_size)
 
       /* Now just list the operations we handle.  */
     case COND_EXPR:		tcode = Cond_Expr; break;
-    case PLUS_EXPR:		tcode = Plus_Expr; break;
     case MINUS_EXPR:		tcode = Minus_Expr; break;
     case MULT_EXPR:		tcode = Mult_Expr; break;
     case TRUNC_DIV_EXPR:	tcode = Trunc_Div_Expr; break;
@@ -8138,20 +8138,28 @@ annotate_value (tree gnu_size)
     case EQ_EXPR:		tcode = Eq_Expr; break;
     case NE_EXPR:		tcode = Ne_Expr; break;
 
+    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;
+	  wide_int op1 = wi::neg (TREE_OPERAND (gnu_size, 1));
+	  pre_op1 = annotate_value (wide_int_to_tree (sizetype, op1));
+	}
+      else
+	tcode = Plus_Expr;
+      break;
+
     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 (op1, TYPE_PRECISION (sizetype));
-	  if (wi::neg_p (signed_op1))
-	    {
-	      op1 = wide_int_to_tree (sizetype, wi::neg (signed_op1));
-	      pre_op1 = annotate_value (build1 (NEGATE_EXPR, sizetype, op1));
-	    }
+	  wide_int op1 = wi::sext (TREE_OPERAND (gnu_size, 1),
+				   TYPE_PRECISION (sizetype));
+	  pre_op1 = annotate_value (wide_int_to_tree (sizetype, op1));
 	}
       break;