[Bug c/85997] Bogus -Wvla warning from function array argument with size expression

[kari.nurmela at iki dot fi]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85997

--- Comment #4 from Kari Nurmela <kari.nurmela at iki dot fi> ---
Yeah, well, I'm not claiming that there is anything wrong with the code
generation (especially argument passing) here, this is just a really minor
issue about the conformance of -Wvla with its documentation, and about its
general usefulness with C99.

* gcc info says about -Wvla: "Warn if variable length array is used in the
  code." This seems to indicate that the -Wvla alone should mean the "other
  uses of -Wvla" mentioned in Comment #1.

* the example program doesn't use any variable length arrays (how can you use
  one without it existing somewhere?), so triggering the warning "if variable
  length array is used in the code" doesn't seem right. (The actual warning
  message is of course patently true :)

With -std=c90 shouldn't this ideally give a separate error/warning about the 
violation of the constraint on the content of []? Like the one triggered by the
"static" with -pedantic -std=c90: "ISO C90 does not support "static" or type
qualifiers in parameter array declarators [-Wpedantic])".