Fixed exposure instability for a few seconds after initialization on iOS Metal, and cleared out a shader compiler warning at run-time.

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Runtime/AsrContext.cs

@@ -167,7 +167,7 @@ namespace ArmASR
                 
                 // Auto exposure always used to track luma changes in locking logic
                 commandBuffer.SetRenderTarget(_resources.AutoExposure[frameIndex ^ 1]);
-                commandBuffer.ClearRenderTarget(false, true, new Color(-1f, 1e8f, 0f, 0f));
+                commandBuffer.ClearRenderTarget(false, true, new Color(0f, 1e8f, 0f, 0f));
                 
                 // Reset atomic counter to 0
                 commandBuffer.SetRenderTarget(_resources.SpdAtomicCounter);

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Shaders/shaders/fsr2/ffxm_fsr2_compute_luminance_pyramid.h

@@ -19,7 +19,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-FFXM_GROUPSHARED FfxUInt32 spdCounter;
+FFXM_GROUPSHARED FfxUInt32 spdCounter = 0u;
 
 void SpdIncreaseAtomicCounter(FfxUInt32 slice)
 {