[PATCH] D46915: [Fixed Point Arithmetic] Fixed Point Precision Bits and Fixed Point Literals

[Leonard Chan via Phabricator via cfe-commits]

leonardchan added a comment.

In https://reviews.llvm.org/D46915#1162038, @erichkeane wrote:

> See this bug here: https://bugs.llvm.org/show_bug.cgi?id=38161
>
> This patch doesn't seem to properly consider integers, and ignores octals, which I suspect shouldn't be the case.


I just requested an account on bugs.llvm.org and will respond here for now until I can comment on the thread there.

So the syntax for fixed point literals should be the same as that for floating point constants according to clause 6.4.4.2a in the embedded C spec (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf). Integers and octal literals should not be supported since floating point literals can only be declared in decimal or hexadecimal notation.

I can see how the error messages don't seem clear and portray this, and should eventually change it so if the user does provide an integer/octal literal an error along the lines of `"fixed point literals cannot be declared as integers"` should be thrown instead.

The assertion is also something that I will address since this should not be thrown.

To sidetrack a bit also, we are limiting fixed point types to just C for now (https://reviews.llvm.org/D46084) so using `auto` to complete the type is not supported. This is until we come up with an itanium mangling for fixed point types (https://github.com/itanium-cxx-abi/cxx-abi/issues/56).


Repository:
  rC Clang

https://reviews.llvm.org/D46915