Caught by Chromium's MSAN tests:
https://chromium-review.googlesource.com/c/chromium/src/+/1774264/3#message-8031b1ce1959519ccdbfa83113f0d989560148d5

Bug: b/139010488
Bug: chromium:998457
Change-Id: If14f0777155ab892f29eb9b01c0bc6781510381b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/35575Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>