[LLVMdev] RFC: Tail call optimization X86

[Chris Lattner]

On Fri, 5 Oct 2007, Arnold Schwaighofer wrote:
>> to me like llvm-gcc honors that.  Certainly it should.
>
> This would imply one fastcc abi (callee pops args on return) to rule
> them all?
> That is only if fastcall translates to llvm fastcc  of course.

fastcall != fastcc.  fastcall is a well defined convention on x86 that has 
very specific ABI requirements.  fastcc, on the other hand, is an LLVM 
thing, and LLVM is allowed to "innovate" on the abi where it wants to.

There is no requirement for LLVM to handle fastcc and fastcall the same.

-Chris

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