[Migrated] Large array variable initialization (`let arr = [0; 32 * 1024];`) compiles very slowly.

Issue automatically imported from old repo: https://github.com/EmbarkStudios/rust-gpu/issues/1132
Old labels: t: bug
Originally creatd by pyranota on 2024-02-11T13:28:58Z

EDIT(@eddyb): while there are reasons to avoid such arrays, the slowdown is the immediate Rust-GPU bug - I've left unchanged the original text, but used strikethrough for parts that don't apply, IMO.

User should not be able to create large sized arrays in rust-gpu shaders.
Stack is limited, and large sized data-structures should be moved in buffers.
Plus it makes compilation incredibly slow (I assume this syntax [0; SIZE] translates to spirv's [0, 0, 0, 0, 0, ... SIZE])

Expected Behaviour

spirv-builder should throw an error, when user creates large array in stack

Example & Steps To Reproduce

1. Setup basic rust-gpu shader
2. let arr = [0; 32 * 1024];
3. cargo build

System Info

• Rust: rustc 1.75.0 (82e1608df 2023-12-21)
• OS: Pop!_OS
• GPU: nvidia 1060
• SPIR-V: SPIRV-Tools v2022.2-dev unknown hash, 2022-02-16T16:37:15

L’issue ne nomme aucun fichier source ni aucun test ; commencez par le reproducteur minimal de shader rust-gpu utilisant let arr = [0; 32 * 1024];, puis exécutez cargo build et suivez le chemin de compilation responsable du ralentissement. Le travail est considéré comme terminé lorsque cet initialiseur de grand tableau ne rend plus la compilation extrêmement lente, avec un test de régression si l’emplacement du test pertinent peut être identifié.