diff --git a/src/webgpu/shader/execution/expression/call/builtin/extractBits.spec.ts b/src/webgpu/shader/execution/expression/call/builtin/extractBits.spec.ts
index dcc3cfd1d4f7..701709e9fc92 100644
--- a/src/webgpu/shader/execution/expression/call/builtin/extractBits.spec.ts
+++ b/src/webgpu/shader/execution/expression/call/builtin/extractBits.spec.ts
@@ -179,6 +179,11 @@ g.test('u32')
               0b00000000000000000000000010101010
             ),
           },
+          // Difficult edge case involving a MAX_UINT 'count'.
+          {
+            input: [V(5), u32(1), u32(4294967295)],
+            expected: V(2),
+          },
         ]
       );
     }
@@ -319,6 +324,11 @@ g.test('i32')
               0b00000000000000000000000010101010
             ),
           },
+          // Difficult edge case involving a MAX_UINT 'count'.
+          {
+            input: [V(5), u32(1), u32(4294967295)],
+            expected: V(2),
+          },
         ]
       );
     }
diff --git a/src/webgpu/shader/execution/expression/call/builtin/insertBits.spec.ts b/src/webgpu/shader/execution/expression/call/builtin/insertBits.spec.ts
index 7619bed8f8c1..71cd35f37858 100644
--- a/src/webgpu/shader/execution/expression/call/builtin/insertBits.spec.ts
+++ b/src/webgpu/shader/execution/expression/call/builtin/insertBits.spec.ts
@@ -337,7 +337,6 @@ g.test('integer')
           0b01010101010101010101010101010101
         ),
       },
-
       // Zero count
       { input: [pattern, all_1, u32(0), u32(0)], expected: pattern },
       { input: [pattern, all_1, u32(1), u32(0)], expected: pattern },
@@ -368,6 +367,11 @@ g.test('integer')
               0b01010101010101010101010101010101
             ),
           },
+          // Difficult edge case involving a MAX_UINT 'count'.
+          {
+            input: [V(5), V(1), u32(1), u32(4294967295)],
+            expected: V(3),
+          },
         ]
       );
     }