From: Eric Botcazou <ebotcazou@adacore.com>
Date: Fri, 10 Nov 2017 08:24:40 +0000 (+0000)
Subject: utils.c (convert): Add comment and do not fall through to the next case.
X-Git-Tag: releases/gcc-6.5.0~689
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2da244eb81a9ec693788fa70831a8d59d7b48f61;p=thirdparty%2Fgcc.git

utils.c (convert): Add comment and do not fall through to the next case.

	* gcc-interface/utils.c (convert) <RECORD_TYPE>: Add comment and do
	not fall through to the next case.
	<ARRAY_TYPE>: Deal specially with a dereference from another array
	type with the same element type.

From-SVN: r254620
---

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index e41237114c12..17b72d620ea6 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+2017-11-10  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/utils.c (convert) <RECORD_TYPE>: Add comment and do
+	not fall through to the next case.
+	<ARRAY_TYPE>: Deal specially with a dereference from another array
+	type with the same element type.
+
 2017-09-15  Martin Liska  <mliska@suse.cz>
 
 	Backport from mainline
diff --git a/gcc/ada/gcc-interface/utils.c b/gcc/ada/gcc-interface/utils.c
index d1c6da4e30cd..3543567b3657 100644
--- a/gcc/ada/gcc-interface/utils.c
+++ b/gcc/ada/gcc-interface/utils.c
@@ -4642,6 +4642,7 @@ convert (tree type, tree expr)
       return fold (convert_to_real (type, expr));
 
     case RECORD_TYPE:
+      /* Do a normal conversion between scalar and justified modular type.  */
       if (TYPE_JUSTIFIED_MODULAR_P (type) && !AGGREGATE_TYPE_P (etype))
 	{
 	  vec<constructor_elt, va_gc> *v;
@@ -4653,9 +4654,27 @@ convert (tree type, tree expr)
 	  return gnat_build_constructor (type, v);
 	}
 
-      /* ... fall through ... */
+      /* In these cases, assume the front-end has validated the conversion.
+	 If the conversion is valid, it will be a bit-wise conversion, so
+	 it can be viewed as an unchecked conversion.  */
+      return unchecked_convert (type, expr, false);
 
     case ARRAY_TYPE:
+      /* Do a normal conversion between unconstrained and constrained array
+	 type, assuming the latter is a constrained version of the former.  */
+      if (TREE_CODE (expr) == INDIRECT_REF
+	  && ecode == ARRAY_TYPE
+	  && TREE_TYPE (etype) == TREE_TYPE (type))
+	{
+	  tree ptr_type = build_pointer_type (type);
+	  tree t = build_unary_op (INDIRECT_REF, NULL_TREE,
+				   fold_convert (ptr_type,
+						 TREE_OPERAND (expr, 0)));
+	  TREE_READONLY (t) = TREE_READONLY (expr);
+	  TREE_THIS_NOTRAP (t) = TREE_THIS_NOTRAP (expr);
+	  return t;
+	}
+
       /* In these cases, assume the front-end has validated the conversion.
 	 If the conversion is valid, it will be a bit-wise conversion, so
 	 it can be viewed as an unchecked conversion.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e41932554cda..4584af5a152c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2017-11-10  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/opt69.adb: New test.
+
 2017-11-06  Paul Thomas  <pault@gcc.gnu.org>
 
 	Backported from trunk
diff --git a/gcc/testsuite/gnat.dg/opt69.adb b/gcc/testsuite/gnat.dg/opt69.adb
new file mode 100644
index 000000000000..e8c94dae2dc8
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt69.adb
@@ -0,0 +1,28 @@
+-- { dg-do compile }
+-- { dg-options "-O" }
+
+with Ada.Text_IO;
+
+procedure Opt69 is
+
+   procedure Inner
+     (A : String := (1 .. 15 => ASCII.NUL);
+      B : String := (1 .. 5 => ASCII.NUL);
+      C : String := (1 .. 5 => ASCII.NUL))
+   is
+      Aa : String (1 .. 15);
+      Bb : String (1 .. 5);
+      Cc : String (1 .. 5);
+   begin
+      Aa := A;
+      Bb := B;
+      Cc := C;
+
+      Ada.Text_IO.Put_Line (Aa);
+      Ada.Text_IO.Put_Line (Bb);
+      Ada.Text_IO.Put_Line (Cc);
+   end;
+
+begin
+   Inner;
+end;