Correct swizzle assignment on pointer tests (#4682)

The swizzle assignment spec was updated so that creating a SwizzleView
from pointer requires support for pointer_composite_access, so CTS tests
here are updated to correctly handle the interaction between
swizzle_assignment and pointer_composite_access. Execution tests for
swizzle assignment via pointer are now skipped if the
pointer_composite_access language feature is not available, and
validation tests are added to validate both cases.

Bug: crbug.com/534329233

Author: sudonatalie

src/webgpu/shader/execution/statement/swizzle_assignment.spec.ts

@@ -265,6 +265,9 @@ g.test('swizzle_assignment_vars')
       kSwizzleAssignmentCases[t.params.case];
 
     t.skipIf(t.params.address_space === 'storage' && elemType === 'bool');
+    if (t.params.memory_view === 'ptr') {
+      t.skipIfLanguageFeatureNotSupported('pointer_composite_access');
+    }
 
     const vecType = `vec${vecSize}<${elemType}>`;
     const initialValues =
@@ -282,6 +285,7 @@ g.test('swizzle_assignment_vars')
 
     const wgsl = `
 requires swizzle_assignment;
+${t.params.memory_view === 'ptr' ? 'requires pointer_composite_access;' : ''}
 ${elemType === 'f16' ? 'enable f16;' : ''}
 
 struct Outputs {
@@ -380,6 +384,10 @@ g.test('swizzle_compound_assignment')
     const { elemType, vecSize, initial, swizzle, op, rhs, expected } =
       kSwizzleCompoundAssignmentCases[t.params.case];
 
+    if (t.params.memory_view === 'ptr') {
+      t.skipIfLanguageFeatureNotSupported('pointer_composite_access');
+    }
+
     const vecType = `vec${vecSize}<${elemType}>`;
     const initialValues = initial.join(', ');
 
@@ -392,6 +400,7 @@ g.test('swizzle_compound_assignment')
 
     const wgsl = `
 requires swizzle_assignment;
+${t.params.memory_view === 'ptr' ? 'requires pointer_composite_access;' : ''}
 ${elemType === 'f16' ? 'enable f16;' : ''}
 
 struct Outputs {

src/webgpu/shader/validation/statement/swizzle_assignment.spec.ts

@@ -144,3 +144,38 @@ fn main() {
 `;
     t.expectCompileResult(false, code);
   });
+
+g.test('pointer_swizzle_assignment')
+  .desc('Validate swizzle assignments on pointers')
+  .params(u =>
+    u
+      .combine('use_pointer', [true, false] as const)
+      .combine('requires_pointer_composite_access', [true, false] as const)
+      .combine('use_compound', [true, false] as const)
+  )
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const { use_pointer, requires_pointer_composite_access, use_compound } = t.params;
+
+    const requires_directive = requires_pointer_composite_access
+      ? 'requires pointer_composite_access;'
+      : '';
+
+    const lhs = use_pointer ? 'p.xy' : '(*p).xy';
+    const op = use_compound ? '+=' : '=';
+
+    const code = `
+${requires_directive}
+@fragment
+fn main() {
+  var v = vec4f();
+  let p = &v;
+  ${lhs} ${op} vec2f(1.0);
+}
+`;
+
+    const has_feature = t.hasLanguageFeature('pointer_composite_access');
+    const expected = !use_pointer || has_feature;
+
+    t.expectCompileResult(expected, code);
+  });