From d832d51f9e0bc6da25781fa9c2a73b8218493e4e Mon Sep 17 00:00:00 2001
From: Alan Baker <alanbaker@google.com>
Date: Tue, 11 Aug 2026 21:19:06 -0400
Subject: [PATCH 1/2] Subgroup_size_control enables subgroups

* Update to match spec
---
 .../validation/extension/subgroup_size_control.spec.ts      | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts b/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
index 198811798064..a8da762322f7 100644
--- a/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
+++ b/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
@@ -11,8 +11,8 @@ export const g = makeTestGroup(UniqueFeaturesAndLimitsShaderValidationTest);
 
 g.test('enable_subgroup_size_control_requires_subgroups')
   .desc(
-    `Checks that enabling the WGSL extension subgroup_size_control without also enabling the
-     subgroups extension is a compilation error.`
+    `Checks that enabling the WGSL extension subgroup_size_control also enables the
+     subgroups extension.`
   )
   .params(u => u.combine('enableSubgroups', [false, true] as const))
   .beforeAllSubcases(t => {
@@ -24,7 +24,7 @@ g.test('enable_subgroup_size_control_requires_subgroups')
     const { enableSubgroups } = t.params;
 
     t.expectCompileResult(
-      enableSubgroups,
+      true,
       `
         ${enableSubgroups ? 'enable subgroups;' : ''}
         enable subgroup_size_control;

From 473911b8f844fc78c0859c195ad1af0408e46599 Mon Sep 17 00:00:00 2001
From: Alan Baker <alanbaker@google.com>
Date: Wed, 12 Aug 2026 11:45:04 -0400
Subject: [PATCH 2/2] changes for review

---
 .../validation/extension/subgroup_size_control.spec.ts       | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts b/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
index a8da762322f7..4c7b86b4f42c 100644
--- a/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
+++ b/src/webgpu/shader/validation/extension/subgroup_size_control.spec.ts
@@ -28,8 +28,11 @@ g.test('enable_subgroup_size_control_requires_subgroups')
       `
         ${enableSubgroups ? 'enable subgroups;' : ''}
         enable subgroup_size_control;
+        @group(0) @binding(0) var<storage, read_write> out : u32;
         @compute @workgroup_size(1)
-        fn main() {}
+        fn main(@builtin(subgroup_size) size : u32) {
+          out = size;
+        }
       `
     );
   });