[spirv] Stop naga causing undefined behavior in `rayQueryGet*Intersec…

…tion` (#6752)

Co-authored-by: Connor Fitzgerald <[email protected]>

CHANGELOG.md

@@ -40,6 +40,12 @@ Bottom level categories:
 
 ## Unreleased
 
+### Bug Fixes
+
+#### Vulkan
+
+- Stop naga causing undefined behavior when a ray query misses. By @Vecvec in [#6752](https://github.com/gfx-rs/wgpu/pull/6752).
+
 ### Changes
 
 #### Refactored internal trace path parameter

naga/src/back/spv/block.rs

@@ -1736,7 +1736,20 @@ impl BlockContext<'_> {
             }
             crate::Expression::ArrayLength(expr) => self.write_runtime_array_length(expr, block)?,
             crate::Expression::RayQueryGetIntersection { query, committed } => {
-                self.write_ray_query_get_intersection(query, block, committed)
+                let query_id = self.cached[query];
+                let func_id = self
+                    .writer
+                    .write_ray_query_get_intersection_function(committed, self.ir_module);
+                let ray_intersection = self.ir_module.special_types.ray_intersection.unwrap();
+                let intersection_type_id = self.get_type_id(LookupType::Handle(ray_intersection));
+                let id = self.gen_id();
+                block.body.push(Instruction::function_call(
+                    intersection_type_id,
+                    id,
+                    func_id,
+                    &[query_id],
+                ));
+                id
             }
         };
 

naga/src/back/spv/mod.rs

@@ -766,6 +766,8 @@ pub struct Writer {
 
     // Just a temporary list of SPIR-V ids
     temp_list: Vec<Word>,
+
+    ray_get_intersection_function: Option<Word>,
 }
 
 bitflags::bitflags! {