[cfe-dev] Fixed Point Arithmetic Proposal
cfe-dev at lists.llvm.org
Wed Apr 25 09:33:50 PDT 2018
> The C extensions to support embedded processors defined in chapter 4 of
> ISO/IEC TR 18037  defines support for fixed-point arithmetic and fixed
> point data types in C.
Just curious, do you know the state of fixed-point arithmetic in C++? I
recall a talk at CPPcon some while ago, but I don't know that it has made
> All changes will also be made to Clang only. Expanding this into LLVM will
> be considered down the road.
"Expanding this into LLVM [later]" implies two things to me. Might mean
more things to somebody else.
First, in the short term the front-end will emit all the scaling operations
explicitly. Does "expanding this into LLVM" include making LLVM understand
scaled types natively? That sounds like a big project.
Second, in the short term the front-end will describe everything in terms of
the same-size same-signedness integer types. I assume you will eventually
teach the debug-info metadata to describe scaled types? DWARF has supported
scaled types since v3, I don't know whether CodeView does also. Adding this
to LLVM should be relatively straightforward.
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