Messages in this thread | | | Date | Wed, 29 Sep 2021 12:41:46 -0500 | From | Segher Boessenkool <> | Subject | Re: [RFC PATCH] LKMM: Add ctrl_dep() macro for control dependency |
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Hi!
On Wed, Sep 29, 2021 at 02:28:37PM +0200, Florian Weimer wrote: > If you need a specific instruction emitted, you need a compiler > intrinsic or inline assembly.
Not an intrinsic. Builtins (like almost all other code) do not say "generate this particular machine code", they say "generate code that does <this>". That is one reason why builtins are more powerful than inline assembler (another related reason is that they tell the compiler exactly what behaviour is expected).
> I don't think it's possible to piggy-back this on something else.
Unless we get a description of what this does in term of language semantics (instead of generated machine code), there is no hope, even.
Segher
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