[Ada] Fix ICE in SRA pass at -O

[Ada] Fix ICE in SRA pass at -O

[Eric Botcazou]

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The ICE is a fallout of the changes made to support super-alignment of 
standalone objects, which may break type consistency for constructors, 
uncovered on IRIX(!) albeit generic.  The fix is to work harder when 
converting a constructor to a packable version of its type.  However the 
general fix would be quadratic in the number of elements of the constructor 
and this doesn't seem worthwhile, so the attached fix assumes a simple layout 
for constructors and punts otherwise.


2008-06-27  Eric Botcazou  <ebotcazou@adacore.com>

	* utils.c (convert) <CONSTRUCTOR>: When converting it to a packable
	version of its type, attempt to first convert its elements.


2008-06-27  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/aggr9.ad[sb]: New test.
	* gnat.dg/aggr9_pkg.ads: New helper.


-- 
Eric Botcazou

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Index: utils.c
===================================================================
--- utils.c	(revision 137079)
+++ utils.c	(working copy)
@@ -3579,17 +3579,47 @@ convert (tree type, tree expr)
 
     case CONSTRUCTOR:
       /* If we are converting a CONSTRUCTOR to a mere variant type, just make
-	 a new one in the proper type.  Likewise for a conversion between
-	 original and packable version.  */
-      if (code == ecode
-	  && (gnat_types_compatible_p (type, etype)
-	      || (code == RECORD_TYPE
-		  && TYPE_NAME (type) == TYPE_NAME (etype))))
+	 a new one in the proper type.  */
+      if (code == ecode && gnat_types_compatible_p (type, etype))
 	{
 	  expr = copy_node (expr);
 	  TREE_TYPE (expr) = type;
 	  return expr;
 	}
+
+      /* Likewise for a conversion between original and packable version, but
+	 we have to work harder in order to preserve type consistency.  */
+      if (code == ecode
+	  && code == RECORD_TYPE
+	  && TYPE_NAME (type) == TYPE_NAME (etype))
+	{
+	  VEC(constructor_elt,gc) *e = CONSTRUCTOR_ELTS (expr);
+	  unsigned HOST_WIDE_INT len = VEC_length (constructor_elt, e);
+	  VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, len);
+	  tree efield = TYPE_FIELDS (etype), field = TYPE_FIELDS (type);
+	  unsigned HOST_WIDE_INT idx;
+	  tree index, value;
+
+	  FOR_EACH_CONSTRUCTOR_ELT(e, idx, index, value)
+	    {
+	      constructor_elt *elt = VEC_quick_push (constructor_elt, v, NULL);
+	      /* We expect only simple constructors.  Otherwise, punt.  */
+	      if (!(index == efield || index == DECL_ORIGINAL_FIELD (efield)))
+		break;
+	      elt->index = field;
+	      elt->value = convert (TREE_TYPE (field), value);
+	      efield = TREE_CHAIN (efield);
+	      field = TREE_CHAIN (field);
+	    }
+
+	  if (idx == len)
+	    {
+	      expr = copy_node (expr);
+	      TREE_TYPE (expr) = type;
+	      CONSTRUCTOR_ELTS (expr) = v;
+	      return expr;
+	    }
+	}
       break;
 
     case UNCONSTRAINED_ARRAY_REF:

[-- Attachment #3: aggr9.adb --]
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-- { dg-do compile }
-- { dg-options "-O" }

package body Aggr9 is

  procedure Proc (X : R1) is
    M : R2 := (F => X);
  begin
    Send (M);
  end;

end Aggr9;

[-- Attachment #4: aggr9.ads --]
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with Aggr9_Pkg; use Aggr9_Pkg;

package Aggr9 is

  procedure Proc (X : R1);

end Aggr9;

[-- Attachment #5: aggr9_pkg.ads --]
[-- Type: text/x-adasrc, Size: 231 bytes --]

package Aggr9_Pkg is

  type Byte is range 0 .. 255;

  type R1 is
    record
      A,B : Byte;                    
    end record;

  type R2 is
    record
      F : R1;
    end record;

  procedure Send (M : R2);

end Aggr9_Pkg;

Re: [Ada] Fix ICE in SRA pass at -O

[Eric Botcazou]

> 2008-06-27  Eric Botcazou  <ebotcazou@adacore.com>
>
> 	* utils.c (convert) <CONSTRUCTOR>: When converting it to a packable
> 	version of its type, attempt to first convert its elements.

I forgot "Tested on i586-suse-linux and applied on the mainline."

-- 
Eric Botcazou