[llvm-dev] Why did "llvm.memcpy" changed when emitting an object file?

Gaier, Bjoern via llvm-dev llvm-dev at lists.llvm.org
Thu May 9 02:02:06 PDT 2019

Sorry, I was not precise enough with my question.

I wanted to ask if I can give the JIT a hint how it should treat those intrinsic functions. Like "always create a function call" or "always use the intrinsic if available". I know that the Clang compiler has such flags but I don't know if the JIT interfaces has those too.

Kind greetings

-----Original Message-----
From: Tim Northover <t.p.northover at gmail.com>
Sent: Donnerstag, 9. Mai 2019 10:46
To: Gaier, Bjoern <Bjoern.Gaier at horiba.com>
Cc: Doerfert, Johannes <jdoerfert at anl.gov>; llvm-dev <llvm-dev at lists.llvm.org>
Subject: Re: [llvm-dev] Why did "llvm.memcpy" changed when emitting an object file?

On Thu, 9 May 2019 at 09:04, Gaier, Bjoern <Bjoern.Gaier at horiba.com> wrote:
> Can I influence if intrinsics are lowered or not?

You can't guarantee memcpy won't be called, if that's what you mean.
If nothing else, most targets simply don't have the code to build a physical loop to do the copy. You have to find a way to provide it in your JIT.


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