Re: [088/nnn] poly_int: expand_expr_real_2

[Jeff Law]

On 10/23/2017 11:35 AM, Richard Sandiford wrote:
> This patch makes expand_expr_real_2 cope with polynomial mode sizes
> when handling conversions involving a union type.
> 
> 
> 2017-10-23  Richard Sandiford  
>   Alan Hayward  
>   David Sherwood  
> 
> gcc/
>   * expr.c (expand_expr_real_2): When handling conversions involving
>   unions, apply tree_to_poly_uint64 to the TYPE_SIZE rather than
>   multiplying int_size_in_bytes by BITS_PER_UNIT.  Treat GET_MODE_BISIZE
>   as a poly_uint64 too.
OK.
jeff

[088/nnn] poly_int: expand_expr_real_2

[Richard Sandiford]

This patch makes expand_expr_real_2 cope with polynomial mode sizes
when handling conversions involving a union type.


2017-10-23  Richard Sandiford  
Alan Hayward  
David Sherwood  

gcc/
* expr.c (expand_expr_real_2): When handling conversions involving
unions, apply tree_to_poly_uint64 to the TYPE_SIZE rather than
multiplying int_size_in_bytes by BITS_PER_UNIT.  Treat GET_MODE_BISIZE
as a poly_uint64 too.

Index: gcc/expr.c
===
--- gcc/expr.c  2017-10-23 17:25:30.704136008 +0100
+++ gcc/expr.c  2017-10-23 17:25:34.105013764 +0100
@@ -8354,11 +8354,14 @@ #define REDUCE_BIT_FIELD(expr)  (reduce_b
  && !TYPE_REVERSE_STORAGE_ORDER (type));
 
  /* Store this field into a union of the proper type.  */
+ poly_uint64 op0_size
+   = tree_to_poly_uint64 (TYPE_SIZE (TREE_TYPE (treeop0)));
+ poly_uint64 union_size = GET_MODE_BITSIZE (mode);
  store_field (target,
-  MIN ((int_size_in_bytes (TREE_TYPE
-   (treeop0))
-* BITS_PER_UNIT),
-   (HOST_WIDE_INT) GET_MODE_BITSIZE (mode)),
+  /* The conversion must be constructed so that
+ we know at compile time how many bits
+ to preserve.  */
+  ordered_min (op0_size, union_size),
   0, 0, 0, TYPE_MODE (valtype), treeop0, 0,
   false, false);
}