| 20 Oct 2021 |
 jimb | Loads are special in that it matters when they're evaluated. We have special logic to bake them. | 18:23:55 |
| jimb | It might be a pain for front ends... | 18:24:57 |
 kvark | Interesting thought! | 18:25:29 |
| jimb | My secret agenda is that bake_ref_count is deceptively critical to Naga's correctness, and if I had 72 hours in the day I would want to make things that are that important at least look important | 18:27:09 |
| jimb | but we've discussed that before | 18:27:26 |
| kvark | Actually, Load isn't the only exception here. There is also ImageLoad | 18:28:41 |
| jimb | Right, and for the same reason | 18:29:42 |
| jimb | and ImageSample | 18:29:53 |
| kvark | No, imagesample is not in this category | 18:32:01 |
| kvark | It's pure | 18:32:10 |
| kvark | And ImageLoad is a concern only for storage images, not regular ones | 18:33:11 |
| kvark | So if we make it a statement, it would be awkward to justify for regular textures | 18:33:42 |
| jimb | Oh, I see. Because they're accessing read-only resources, they're not sensitive to side-effects | 18:55:10 |
| jimb | * Oh, I see. Because they're accessing read-only resources, they're not sensitive to side-effects | 18:55:22 |
| kvark | right | 19:31:38 |
| jimb | In reply to @kvark:matrix.org
I don't see the concern yet. The backend decides which expressions are baked and which aren't. It could easily check if an expression is used to index and force baking it. Yes, this should work. | 20:28:00 |
| jimb | In reply to @jcapucho:matrix.org
Couldn't you make it an IR transformation and let the reference count do it's job? Yes, if we did it in the IR, then everything would Just Work. But our IR isn't easy to manipulate; it's not designed for that. kvark and I decided at the outset that we'd try just handling bounds checks in the back ends, and see how it turns out. | 20:29:31 |
| jimb | If ultimately I'm able to put most of the logic in a processor, and just give the back ends a plan they can follow blindly, then I think things should be fine. | 20:30:08 |
 cwfitzgerald | on the note of IR stuff, I was thinking a way of making "optimization not naga's problem" would be letting (through unsafe) shaders opt out of bounds checks on an access by access basis, then an optimizer which was generating wgsl could do the optimization and omit the bounds checks it knew to be redundant | 20:50:08 |
| cwfitzgerald | it wouldn't help web elide bounds checks, but it would help native | 20:50:53 |
| cwfitzgerald | * on the note of IR stuff, I was thinking a way of making "optimization not naga's problem" would be letting (through unsafe) shaders opt out of bounds checks on an access by access basis, then an optimizer which was generating wgsl could do the optimization and omit the bounds checks it knew to be redundant | 20:51:28 |
| kvark | when would native need a bounds check? if you need a check, just do it yourself :) | 20:52:21 |
| cwfitzgerald | yeah I mean fair :D | 20:52:48 |
| cwfitzgerald | in all seriousness though that's a good point, we already have a "turn off all bounds checks" mode, and a wgsl optimizer that wanted to present safety could just add them itself | 20:54:22 |
| cwfitzgerald | * in all seriousness though that's a good point, we already have a "turn off all bounds checks" mode, and a wgsl optimizer that wanted to present safety could just add them itself | 20:54:28 |
| cwfitzgerald | I don't think wgpu/naga is privileged for writing bounds checks, except maybe with descriptor indexing needing to side channel the array lengths in | 20:55:41 |
| cwfitzgerald | * I don't think wgpu/naga is privileged for writing bounds checks, except maybe with descriptor indexing needing to side channel the array lengths in | 20:55:49 |
| 21 Oct 2021 |
| jimb | Rust 1.56 lets you specify MSRV in Cargo.toml | 18:24:33 |
 jcapucho | Now that you speak about MSRV, 1.46 is now the default for Ubuntu so we should consider upgrading (speaking about Ubuntu since that was the one with oldest toolchain) | 18:27:52 |
| 22 Oct 2021 |
| cwfitzgerald | In reply to @jimb:mozilla.org
Rust 1.56 lets you specify MSRV in Cargo.toml Ironically having an msrv to have an msrv | 00:29:46 |
