trans.c (pos_to_constructor): Skip conversions to an unconstrained array type.

	* gcc-interface/trans.c (pos_to_constructor): Skip conversions to an
	unconstrained array type.

From-SVN: r251691

gcc/ada/ChangeLog

+2017-09-05  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/trans.c (pos_to_constructor): Skip conversions to an
+	unconstrained array type.
+
 2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>

gcc/ada/gcc-interface/trans.c

@@ -9826,7 +9826,14 @@ pos_to_constructor (Node_Id gnat_expr, tree gnu_array_type,
 				       gnat_component_type);
       else
 	{
-	  gnu_expr = gnat_to_gnu (gnat_expr);
+	  /* If the expression is a conversion to an unconstrained array type,
+	     skip it to avoid spilling to memory.  */
+	  if (Nkind (gnat_expr) == N_Type_Conversion
+	      && Is_Array_Type (Etype (gnat_expr))
+	      && !Is_Constrained (Etype (gnat_expr)))
+	    gnu_expr = gnat_to_gnu (Expression (gnat_expr));
+	  else
+	    gnu_expr = gnat_to_gnu (gnat_expr);
 
 	  /* Before assigning the element to the array, make sure it is
 	     in range.  */

gcc/testsuite/ChangeLog

+2017-09-05  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* testsuite/gnat.dg/array29.ad[sb]: New test.
+
 2017-09-05  Martin Liska  <mliska@suse.cz>
 
 	PR tree-optimization/82032

gcc/testsuite/gnat.dg/array29.adb

+-- { dg-do compile }
+-- { dg-options "-O" }
+
+package body Array29 is
+
+  procedure Copy (Src : in Matrix; Dst : out Matrix) is
+  begin
+    for I in Src'Range (1) loop
+      for J in Src'Range (2) loop
+        Dst (I, J) := Src (I, J);
+      end loop;
+    end loop;
+  end;
+
+  procedure Proc is
+    N : constant := 2;
+    FM1 : constant Matrix (1 .. N, 1 .. N) := ((1.0, 2.0), (3.0, 4.0));
+    FM2 : constant Matrix (1 .. N, 1 .. N) := ((1.0, 2.0), (3.0, 4.0));
+    A : constant array (1 .. 2) of Matrix (1 .. N, 1 .. N)
+      := (Matrix (FM1), Matrix (FM2));
+    Final : Matrix (1 .. N, 1 .. N);
+  begin
+    Copy (Src => A (1), Dst => Final);
+  end;
+
+end Array29;

gcc/testsuite/gnat.dg/array29.ads

+package Array29 is
+
+  type Matrix is array (Integer range <>, Integer range <>) of Long_Float;
+
+  procedure Proc;
+
+end Array29;