Description
Expected Behaviour
Able to compile a SPIR-V compute shader using the log10 operation.
Example & Steps To Reproduce
Minimal reproducer available at: https://github.com/bspeice/rust-gpu-log10-err/blob/main/crates/shader/src/lib.rs
I hit an error when spirv-builder attempted to run a shader through spirv-val:
#![no_std]
use spirv_std::glam::UVec3;
use spirv_std::num_traits::Float;
use spirv_std::spirv;
#[spirv(compute(threads(1)))]
pub fn render_image_histogram(
#[spirv(global_invocation_id)] _global_id: UVec3,
#[spirv(storage_buffer, descriptor_set = 0, binding = 0)] input: &[f32],
#[spirv(storage_buffer, descriptor_set = 0, binding = 1)] output: &mut [f32],
) {
output[0] = input[0].log10();
} error: Expected int scalar or vector type as Result Type: IMul
|
= note: module `/home/bspeice/Development/log10/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shader.spv`
warning: an unknown error occurred
|
= note: spirv-opt failed, leaving as unoptimized
= note: module `/home/bspeice/Development/log10/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shader.spv`
error: error:0:0 - Expected int scalar or vector type as Result Type: IMul
%35 = OpIMul %float %float_0_434294492 %34
|
= note: spirv-val failed
= note: module `/home/bspeice/Development/log10/target/spirv-builder/spirv-unknown-vulkan1.2/release/deps/shader.spv`
warning: `shader` (lib) generated 1 warning
error: could not compile `shader` (lib) due to 2 previous errors; 1 warning emitted
Error: BuildFailed
If I understand the output correctly, codegen produced a SPIR-V output that included an OpIMul, when it should have been an OpFMul. spirv-opt then failed, and the output was left unoptimized. Afterward, spirv-val failed validation for the same problem that spirv-opt failed on.
It seems like log10 is implemented with a change of base, so I'm a bit confused on why this gets turned into an OpIMul. Writing the operation out as 1.0 / 10.0.ln() * input[0].ln() seems to fix things.
Separately, cargo warns me that the Float trait is unused (but fails to compile without); guessing that's a bug, but not sure if related:
warning: unused import: `spirv_std::num_traits::Float`
--> crates/shader/src/lib.rs:3:5
|
3 | use spirv_std::num_traits::Float;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(unused_imports)]` on by default
System Info
- Rust: rustc 1.84.0-nightly (b19329a37 2024-11-21) (spirv-builder 1d76d59)
- OS: Ubuntu 24.04
- GPU: NVidia RTX 3070
- SPIR-V: SPIRV-Tools v2023.6 unknown hash, 2024-02-07T17:19:14+00:00