Allow wgpu-core to use new naga optimizations for dot4{I, U}8Packed (#7595)

* [wgpu-hal] Use highest available SPIR-V version

* [wgpu-hal] Expose capabilities `DotProductInput*`

* Introduce `{PhysicalDeviceFeatures, PrivateCapabilities}::shader_integer_dot_product`

Author: robamler

CHANGELOG.md

@@ -85,6 +85,10 @@ Naga now infers the correct binding layout when a resource appears only in an as
 
 - Remove the need for dxil.dll. By @teoxoy in [#7566](https://github.com/gfx-rs/wgpu/pull/7566)
 
+#### Vulkan
+
+- Use highest SPIR-V version supported by Vulkan API version. By @robamler in [#7595](https://github.com/gfx-rs/wgpu/pull/7595)
+
 ### Bug Fixes
 
 #### Naga

wgpu-hal/src/vulkan/adapter.rs

@@ -123,6 +123,10 @@ pub struct PhysicalDeviceFeatures {
 
     /// Features proved by `VK_EXT_mesh_shader`
     mesh_shader: Option<vk::PhysicalDeviceMeshShaderFeaturesEXT<'static>>,
+
+    /// Features provided by `VK_KHR_shader_integer_dot_product`, promoted to Vulkan 1.3.
+    shader_integer_dot_product:
+        Option<vk::PhysicalDeviceShaderIntegerDotProductFeaturesKHR<'static>>,
 }
 
 impl PhysicalDeviceFeatures {
@@ -187,6 +191,9 @@ impl PhysicalDeviceFeatures {
         if let Some(ref mut feature) = self.mesh_shader {
             info = info.push_next(feature);
         }
+        if let Some(ref mut feature) = self.shader_integer_dot_product {
+            info = info.push_next(feature);
+        }
         info
     }
 
@@ -499,6 +506,16 @@ impl PhysicalDeviceFeatures {
             } else {
                 None
             },
+            shader_integer_dot_product: if device_api_version >= vk::API_VERSION_1_3
+                || enabled_extensions.contains(&khr::shader_integer_dot_product::NAME)
+            {
+                Some(
+                    vk::PhysicalDeviceShaderIntegerDotProductFeaturesKHR::default()
+                        .shader_integer_dot_product(private_caps.shader_integer_dot_product),
+                )
+            } else {
+                None
+            },
         }
     }
 
@@ -1006,6 +1023,11 @@ impl PhysicalDeviceProperties {
             if requested_features.intersects(wgt::Features::EXPERIMENTAL_MESH_SHADER) {
                 extensions.push(khr::maintenance4::NAME);
             }
+
+            // Optional `VK_KHR_shader_integer_dot_product`
+            if self.supports_extension(khr::shader_integer_dot_product::NAME) {
+                extensions.push(khr::shader_integer_dot_product::NAME);
+            }
         }
 
         // Optional `VK_KHR_swapchain_mutable_format`
@@ -1496,6 +1518,16 @@ impl super::InstanceShared {
                 features2 = features2.push_next(next);
             }
 
+            // `VK_KHR_shader_integer_dot_product` is promoted to 1.3
+            if capabilities.device_api_version >= vk::API_VERSION_1_3
+                || capabilities.supports_extension(khr::shader_integer_dot_product::NAME)
+            {
+                let next = features
+                    .shader_integer_dot_product
+                    .insert(vk::PhysicalDeviceShaderIntegerDotProductFeatures::default());
+                features2 = features2.push_next(next);
+            }
+
             unsafe { get_device_properties.get_physical_device_features2(phd, &mut features2) };
             features2.features
         } else {
@@ -1679,6 +1711,9 @@ impl super::Instance {
                 .properties
                 .limits
                 .max_sampler_allocation_count,
+            shader_integer_dot_product: phd_features
+                .shader_integer_dot_product
+                .is_some_and(|ext| ext.shader_integer_dot_product != 0),
         };
         let capabilities = crate::Capabilities {
             limits: phd_capabilities.to_wgpu_limits(),
@@ -1971,13 +2006,24 @@ impl super::Adapter {
             if features.contains(wgt::Features::EXPERIMENTAL_RAY_HIT_VERTEX_RETURN) {
                 capabilities.push(spv::Capability::RayQueryPositionFetchKHR)
             }
+            if self.private_caps.shader_integer_dot_product {
+                // See <https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_shader_integer_dot_product.html#_new_spir_v_capabilities>.
+                capabilities.extend(&[
+                    spv::Capability::DotProductInputAllKHR,
+                    spv::Capability::DotProductInput4x8BitKHR,
+                    spv::Capability::DotProductInput4x8BitPackedKHR,
+                    spv::Capability::DotProductKHR,
+                ]);
+            }
             spv::Options {
-                lang_version: if features
-                    .intersects(wgt::Features::SUBGROUP | wgt::Features::SUBGROUP_VERTEX)
-                {
-                    (1, 3)
-                } else {
-                    (1, 0)
+                lang_version: match self.phd_capabilities.device_api_version {
+                    // Use maximum supported SPIR-V version according to
+                    // <https://github.com/KhronosGroup/Vulkan-Docs/blob/19b7651/appendices/spirvenv.adoc?plain=1#L21-L40>.
+                    vk::API_VERSION_1_0..vk::API_VERSION_1_1 => (1, 0),
+                    vk::API_VERSION_1_1..vk::API_VERSION_1_2 => (1, 3),
+                    vk::API_VERSION_1_2..vk::API_VERSION_1_3 => (1, 5),
+                    vk::API_VERSION_1_3.. => (1, 6),
+                    _ => unreachable!(),
                 },
                 flags,
                 capabilities: Some(capabilities.iter().cloned().collect()),

wgpu-hal/src/vulkan/mod.rs

@@ -528,6 +528,14 @@ struct PrivateCapabilities {
     zero_initialize_workgroup_memory: bool,
     image_format_list: bool,
     maximum_samplers: u32,
+
+    /// True if this adapter supports the [`VK_KHR_shader_integer_dot_product`] extension
+    /// (promoted to Vulkan 1.3).
+    ///
+    /// This is used to generate optimized code for WGSL's `dot4{I, U}8Packed`.
+    ///
+    /// [`VK_KHR_shader_integer_dot_product`]: https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_shader_integer_dot_product.html
+    shader_integer_dot_product: bool,
 }
 
 bitflags::bitflags!(