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Fix minor bug in VIEW_CONVERT_EXPR expander


There is a minor bug in the VIEW_CONVERT_EXPR expander in the 4.x series of 
compilers, visible mostly on big-endian platforms:

      /* If both modes are integral, then we can convert from one to the
	 other.  */
      else if (SCALAR_INT_MODE_P (GET_MODE (op0)) && SCALAR_INT_MODE_P (mode))
	op0 = convert_modes (mode, GET_MODE (op0), op0,
			     TYPE_UNSIGNED (TREE_TYPE (treeop0)));

Integral mode doesn't imply integral type, the type can be a small record or 
array, in which case the TYPE_UNSIGNED test doesn't make sense and the result 
is wrong on big-endian platforms.

Fixed thusly, tested on x86_64-suse-linux and SPARC/Solaris, applied on the 
mainline as obvious.


2010-04-23  Eric Botcazou  <ebotcazou@adacore.com>

	* expr.c (expand_expr_real_1) <VIEW_CONVERT_EXPR>: Only use conversion
	between modes if both types are integral.


2010-04-23  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/unchecked_convert5.adb: New test.


-- 
Eric Botcazou
Index: expr.c
===================================================================
--- expr.c	(revision 158539)
+++ expr.c	(working copy)
@@ -9353,9 +9353,8 @@ expand_expr_real_1 (tree exp, rtx target
 	    op0 = force_reg (GET_MODE (op0), op0);
 	  op0 = gen_lowpart (mode, op0);
 	}
-      /* If both modes are integral, then we can convert from one to the
-	 other.  */
-      else if (SCALAR_INT_MODE_P (GET_MODE (op0)) && SCALAR_INT_MODE_P (mode))
+      /* If both types are integral, convert from one mode to the other.  */
+      else if (INTEGRAL_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (treeop0)))
 	op0 = convert_modes (mode, GET_MODE (op0), op0,
 			     TYPE_UNSIGNED (TREE_TYPE (treeop0)));
       /* As a last resort, spill op0 to memory, and reload it in a
-- { dg-do run { target hppa*-*-* sparc*-*-* powerpc*-*-* } }

with Unchecked_Conversion;

procedure Unchecked_Convert5 is

  subtype c_1 is string(1..1);

  function int2c1 is  -- { dg-warning "different sizes" }
    new unchecked_conversion (source => integer, target => c_1);

  c1 : c_1;

begin

  c1 := int2c1(16#12#);

  if c1 (1) /= ASCII.Nul then
    raise Program_Error;
  end if;

end;

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