WebGPU f16 support (f16 bounty part 2) (#8653)

* WebGPU f16 support

* Don't enable f16 yet

* dtype tests passing after bitcast fix

* Maybe all WebGPU green?

* Require shader-f16 in examples

* Minor wgsl touchup

* 1 line shorter

* Simpler

* Add transcendetal support

* log2 nan location mismatch on Vulkan

* Nan skips

examples/webgpu/efficientnet/index.html

@@ -49,7 +49,10 @@ canvas {  display: none; }
 	const getDevice = async () => {
 		if (!navigator.gpu) error("WebGPU not supported.");
 		const adapter = await navigator.gpu.requestAdapter();
-		return await adapter.requestDevice();
+		return await adapter.requestDevice({
+			requiredFeatures: ["shader-f16"],
+			powerPreference: "high-performance"
+		});
 	};
 
 	const timer = async (func, label = "") => {

examples/webgpu/stable_diffusion/index.html

@@ -322,7 +322,9 @@
             requiredLimits.maxBufferSize = maxBufferSizeInSDModel;
             
             return await adapter.requestDevice({
-                requiredLimits
+                requiredLimits,
+                requiredFeatures: ["shader-f16"],
+                powerPreference: "high-performance"
             });
         };
 

examples/webgpu/yolov8/index.html

@@ -251,7 +251,10 @@
         const getDevice = async () => {
             if (!navigator.gpu) return false;
             const adapter = await navigator.gpu.requestAdapter();
-            return await adapter.requestDevice();
+            return await adapter.requestDevice({
+                requiredFeatures: ["shader-f16"],
+                powerPreference: "high-performance"
+		    });
         };
         
         function processOutput(output, img_width, img_height) {