Re: [094/nnn] poly_int: expand_ifn_atomic_compare_exchange_into_call

[Jeff Law]

On 10/23/2017 11:37 AM, Richard Sandiford wrote:
> This patch makes the mode size assumptions in
> expand_ifn_atomic_compare_exchange_into_call a bit more
> explicit, so that a later patch can add a to_constant () call.
> 
> 
> 2017-10-23  Richard Sandiford  
>   Alan Hayward  
>   David Sherwood  
> 
> gcc/
>   * builtins.c (expand_ifn_atomic_compare_exchange_into_call): Assert
>   that the mode size is in the set {1, 2, 4, 8, 16}.
OK.
jeff

[094/nnn] poly_int: expand_ifn_atomic_compare_exchange_into_call

[Richard Sandiford]

This patch makes the mode size assumptions in
expand_ifn_atomic_compare_exchange_into_call a bit more
explicit, so that a later patch can add a to_constant () call.


2017-10-23  Richard Sandiford  
Alan Hayward  
David Sherwood  

gcc/
* builtins.c (expand_ifn_atomic_compare_exchange_into_call): Assert
that the mode size is in the set {1, 2, 4, 8, 16}.

Index: gcc/builtins.c
===
--- gcc/builtins.c  2017-10-23 17:22:18.226824652 +0100
+++ gcc/builtins.c  2017-10-23 17:25:41.647742640 +0100
@@ -5838,9 +5838,12 @@ expand_ifn_atomic_compare_exchange_into_
   /* Skip the boolean weak parameter.  */
   for (z = 4; z < 6; z++)
 vec->quick_push (gimple_call_arg (call, z));
+  /* At present we only have BUILT_IN_ATOMIC_COMPARE_EXCHANGE_{1,2,4,8,16}.  */
+  unsigned int bytes_log2 = exact_log2 (GET_MODE_SIZE (mode));
+  gcc_assert (bytes_log2 < 5);
   built_in_function fncode
 = (built_in_function) ((int) BUILT_IN_ATOMIC_COMPARE_EXCHANGE_1
-  + exact_log2 (GET_MODE_SIZE (mode)));
+  + bytes_log2);
   tree fndecl = builtin_decl_explicit (fncode);
   tree fn = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (fndecl)),
fndecl);