Revert "Vulkan: Enforce fixed subgroup size for compute shaders."

This reverts commit 56f1678437.

Reason for revert: crbug.com/1059205
Bug: chromium:1059205

Original change's description:
> Vulkan: Enforce fixed subgroup size for compute shaders.
>
> This CL ensures that, on architectures with a varying subgroup size,
> compute shaders are always compiled with a fixed subgroup size to
> avoid consistency issues when one shader writes data in a subgroup-size
> dependent layout to GPU memory, to be read by another shader in a
> future dispatch.
>
> At the moment, only Intel ICDs are known to implement this [1],
> and the code uses a heuristics to chose the size of 16, which seems to
> be the sweet spot according to Intel engineers.
>
> + Update the PNextChainBuilder class to deal with the fact that
>   VkComputePipelineCreateInfo::pNext is defined as a const void*,
>   which created compiler errors in the previous implementation.
>
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=108875
>
> Change-Id: I332faa53b9f854a8abe43a7271f30d8c5deb2142
> Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/16021
> Commit-Queue: Corentin Wallez <cwallez@chromium.org>
> Reviewed-by: Corentin Wallez <cwallez@chromium.org>

TBR=cwallez@google.com,cwallez@chromium.org,enga@chromium.org,enga@google.com,david.turner.dev@gmail.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I922eccc310505da4b4a9fc853335733ca4900fc8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/16521
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/dawn_native/vulkan/ComputePipelineVk.cpp

@@ -18,7 +18,6 @@
 #include "dawn_native/vulkan/FencedDeleter.h"
 #include "dawn_native/vulkan/PipelineLayoutVk.h"
 #include "dawn_native/vulkan/ShaderModuleVk.h"
-#include "dawn_native/vulkan/UtilsVulkan.h"
 #include "dawn_native/vulkan/VulkanError.h"
 
 namespace dawn_native { namespace vulkan {
@@ -51,18 +50,6 @@ namespace dawn_native { namespace vulkan {
         createInfo.stage.pSpecializationInfo = nullptr;
 
         Device* device = ToBackend(GetDevice());
-
-        PNextChainBuilder extChain(&createInfo);
-
-        VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT subgroupSizeInfo = {};
-        uint32_t computeSubgroupSize = device->GetComputeSubgroupSize();
-        if (computeSubgroupSize != 0u) {
-            extChain.Add(
-                &subgroupSizeInfo,
-                VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_REQUIRED_SUBGROUP_SIZE_CREATE_INFO_EXT);
-            subgroupSizeInfo.requiredSubgroupSize = computeSubgroupSize;
-        }
-
         return CheckVkSuccess(
             device->fn.CreateComputePipelines(device->GetVkDevice(), ::VK_NULL_HANDLE, 1,
                                               &createInfo, nullptr, &*mHandle),

src/dawn_native/vulkan/DeviceVk.cpp

@@ -388,8 +388,6 @@ namespace dawn_native { namespace vulkan {
 
             *dst = mDeviceInfo.featuresExtensions.subgroupSizeControl;
             featuresChain.Add(dst);
-
-            mComputeSubgroupSize = FindComputeSubgroupSize();
         }
 
         // Always require independentBlend because it is a core Dawn feature
@@ -466,33 +464,6 @@ namespace dawn_native { namespace vulkan {
         return usedKnobs;
     }
 
-    uint32_t Device::FindComputeSubgroupSize() const {
-        if (!mDeviceInfo.subgroupSizeControl) {
-            return 0;
-        }
-
-        const VkPhysicalDeviceSubgroupSizeControlPropertiesEXT& ext =
-            mDeviceInfo.propertiesExtensions.subgroupSizeControl;
-
-        if (ext.minSubgroupSize == ext.maxSubgroupSize) {
-            return 0;
-        }
-
-        // At the moment, only Intel devices support varying subgroup sizes
-        // and 16, which is the next value after the minimum of 8, is the sweet
-        // spot according to [1]. Hence the following heuristics, which may
-        // need to be adjusted in the future for other architectures, or if
-        // a specific API is added to let client code select the size..
-        //
-        // [1] https://bugs.freedesktop.org/show_bug.cgi?id=108875
-        uint32_t subgroupSize = ext.minSubgroupSize * 2;
-        if (subgroupSize <= ext.maxSubgroupSize) {
-            return subgroupSize;
-        } else {
-            return ext.minSubgroupSize;
-        }
-    }
-
     void Device::GatherQueueFromDevice() {
         fn.GetDeviceQueue(mVkDevice, mQueueFamily, 0, &mQueue);
     }

src/dawn_native/vulkan/DeviceVk.h

@@ -100,12 +100,6 @@ namespace dawn_native { namespace vulkan {
 
         ResourceMemoryAllocator* GetResourceMemoryAllocatorForTesting() const;
 
-        // Return the fixed subgroup size to use for compute shaders on this device,
-        // or 0 if none needs to be set.
-        uint32_t GetComputeSubgroupSize() const {
-            return mComputeSubgroupSize;
-        }
-
       private:
         ResultOrError<BindGroupBase*> CreateBindGroupImpl(
             const BindGroupDescriptor* descriptor) override;
@@ -136,7 +130,6 @@ namespace dawn_native { namespace vulkan {
         ResultOrError<VulkanDeviceKnobs> CreateDevice(VkPhysicalDevice physicalDevice);
         void GatherQueueFromDevice();
 
-        uint32_t FindComputeSubgroupSize() const;
         void InitTogglesFromDriver();
         void ApplyDepth24PlusS8Toggle();
 
@@ -151,7 +144,6 @@ namespace dawn_native { namespace vulkan {
         VkDevice mVkDevice = VK_NULL_HANDLE;
         uint32_t mQueueFamily = 0;
         VkQueue mQueue = VK_NULL_HANDLE;
-        uint32_t mComputeSubgroupSize = 0;
 
         std::unique_ptr<DescriptorSetService> mDescriptorSetService;
         std::unique_ptr<FencedDeleter> mDeleter;