agx: Mask shifts in the backend
This gives our shifts SM5 behaviour at the cost of a little extra ALU. That way, we match NIR's shifts.
This fixes unsoundness of GLSL expressions like "a << (b & 31)", where the & would mistakenly get optimized away.
Closes: #8181 (closed) Signed-off-by: Alyssa Rosenzweig alyssa@rosenzweig.io Reported-by: Georg Lehmann dadschoorse@gmail.com