C Backend's future

Thanks. I've updated the documentation and examples in r119169.

I didn't update the OCaml documentation or examples yet. It looks
like the OCaml bindings don't expose basicaa yet, though it should
be easy to add for someone familiar with the bindings.

Dan

Hi Dan,

The tutorial in r119335 does not build : the basicAA pass creation needs to be declared. This is addressed with the 'missing-include' patch, which updates both source code & documentation.

The second point is that beside basicAA, to get the optimizations as shown in the tutorial, (sin(x)*sin(x) -> sin(x)^2), some attributes need to be set on 'sin'. Patch 'set-attribute' address this. Of course, this is probably not the right way to achieve this in real life with a real programming language / environment, but within the scope of the kaleidoscope, this should be sufficient. This patch updates both the source code & documentation.

Best regards,

kaleidoscope-set-attribute.patch (6.42 KB)

kaleidoscope-missing-include.patch (3.74 KB)

Hi Dan,

The tutorial in r119335 does not build : the basicAA pass creation needs to be declared. This is addressed with the 'missing-include' patch, which updates both source code & documentation.

Applied, thanks.

The second point is that beside basicAA, to get the optimizations as shown in the tutorial, (sin(x)*sin(x) -> sin(x)^2), some attributes need to be set on 'sin'. Patch 'set-attribute' address this. Of course, this is probably not the right way to achieve this in real life with a real programming language / environment, but within the scope of the kaleidoscope, this should be sufficient. This patch updates both the source code & documentation.

Did the code in the tutorial work at some point? Offhand, I wouldn't expect
any of my recent changes to have affected this. I'm reluctant to fix this
without understanding how the original code was intended to work.

Dan

Hi Dan,

Did the code in the tutorial work at some point? Offhand, I wouldn't expect
any of my recent changes to have affected this. I'm reluctant to fix this
without understanding how the original code was intended to work.

The code works, but not as shown in the tutorial. In the tutorial, it shows that multiple calls to pure functions (sin, cos) can be optimized. Without the patch, this does not show up any longer. So we need to update either the tutorial or the code.

I think it is better to tweak the source code, because it is a good demonstration of what llvm can do. The tutorial/Chapter 4 is about JIT & optimizer; 2 optimizations are demonstrated : constant folding and pure functions handling. Only showing constant folding does not seem very appealing for an optimizer :slight_smile:

Best regards,

Please contact the tutorial author.

Thanks,

Dan