On 8/12/20 8:00 PM, Segher Boessenkool wrote:
> On Wed, Aug 12, 2020 at 03:32:18PM -0500, Peter Bergner wrote:
>> --- a/gcc/config/rs6000/rs6000-call.c
>> +++ b/gcc/config/rs6000/rs6000-call.c
>> @@ -6444,8 +6444,26 @@ machine_mode
>> rs6000_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
>> machine_mode mode,
>> int *punsignedp ATTRIBUTE_UNUSED,
>> - const_tree, int)
>> + const_tree, int for_return)
>> {
>> + /* Warning: this is a static local variable and not always NULL! */
>> + static struct function *fn = NULL;
>
> It may be just me that always misses "static" on locals, heh. But
> please comment what this is *for*: to warn only once per function. You
> could choose a better variable name to say that, too.
Ok, how about this comment then?
@@ -6444,8 +6444,30 @@ machine_mode
rs6000_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
machine_mode mode,
int *punsignedp ATTRIBUTE_UNUSED,
- const_tree, int)
+ const_tree, int for_return)
{
+ /* Warning: this is a static local variable and not always NULL!
+ This function is called multiple times for the same function
+ and return value. PREV_FUNC is used to keep track of the
+ first time we encounter a function's return value in order
+ to not report an error with that return value multiple times. */
+ static struct function *prev_func = NULL;
+
+ /* We do not allow MMA types being used as return values. Only report
+ the invalid return value usage the first time we encounter it. */
+ if (for_return
+ && prev_func != cfun
+ && (mode == POImode || mode == PXImode))
+ {
+ /* Record we have now handled function CFUN, so the next time we
+ are called, we do not re-report the same error. */
+ prev_func = cfun;
+ if (TYPE_CANONICAL (type) != NULL_TREE)
+ type = TYPE_CANONICAL (type);
+ error ("invalid use of MMA type %qs as a function return value",
+ IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
+ }
+
PROMOTE_MODE (mode, *punsignedp, type);
return mode;
Peter
