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LFortran compiles PRIMA

lfortran.org

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Re: LFortran compiles PRIMA

#24

Post by quanto »

> It utilizes a range of Modern Fortran features, including extensive use of optional variables, function pointer passing, and a randomized test driver, among others. Successfully compiling PRIMA requires a compiler with a robust and mature backend, as well as well-developed intermediate passes and a capable parser.

I am not getting a full picture here. What's challenging about PRIMA code base? Does it use some advanced features that are difficult for a compiler to support? Are the mentioned features in the 2008 standard?

What's actually impressive is that LFortran in alpha stage is only 2x slower than GFortran, which goes back decades.

Re: LFortran compiles PRIMA

#26

Post by jamesfinlayson »

rbanffy wrote: post #10
pjmlp wrote: post #5

Earlier quoted context omitted.

I am fully aware of it, however most recent revisions tend not to be adopted by all compilers, and honestly the large majority only cares about keeping existing code running. A bit like C23 and C++23 are here, and the large majority is a mix of C89, C99, C++11, and C++17, as what folks in the trenches care about. Or Java 8 versus Java 24, and so on. Fortran is in a similar position.

How many different platforms out there run Fortran code these days? I’m aware of it being very important in scientific computing (and compiling existing code is critical) but I don’t know many other use cases and different platforms requiring different compilers.

At a previous job there were two fairly old Fortran code bases running on emulated hardware. I think one was using an old proprietary compiler (I want to say from IBM) while the other was almost certainly using some ancient compiler given the emulated hardware that it was running on.

Re: LFortran compiles PRIMA

#27

Post by genewitch »

I'll have to benchmark a library-less Matmul with LFortran, to compare against flang, C, and python versions.

Roughly: 8, 12, 18 units of time, respectively. Python only being twice as slow for the simplest matmul - how much of that is merely the interpreter startup time?

Re: LFortran compiles PRIMA

#28

Post by certik »

quanto wrote: post #24

> It utilizes a range of Modern Fortran features, including extensive use of optional variables, function pointer passing, and a randomized test driver, among others. Successfully compiling PRIMA requires a compiler with a robust and mature backend, as well as well-developed intermediate passes and a capable parser. I am not getting a full picture here. What's challenging about PRIMA code base? Does it use some advan…

It was a lot of corner cases that we had to get right, it's the most advanced code that LFortran can compile. I think none of the features individually is difficult to support, but there were a lot of them.

Re: LFortran compiles PRIMA

#29

Post by pklausler »

pjmlp wrote: post #11
rbanffy wrote: post #10

Earlier quoted context omitted.

How many different platforms out there run Fortran code these days? I’m aware of it being very important in scientific computing (and compiling existing code is critical) but I don’t know many other use cases and different platforms requiring different compilers.

In many HPC cases you are using the platform tools, not gfortran. Also we have one use case that is responsible for OpenCL losing mindshare for scientific community, running Fortran on GPU. Thus I bet at least Intel, NVidia, AMD, Cray, IBM, being relevant ones. Yes, some of them are planning to eventually adopt LFortran to replace their own, like they did with clang, or at least are using LLVM nowadays.

I think that you're conflating LFortran with LLVM Flang.
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