i965/fs: don't propagate 64-bit immediates

They can only be used with 1-src instructions, which practically (since
we should've constant-propagated away all 1-src instructions with 64-bit
immediates in NIR) means that they must be kept in separate MOV's and
can't be propagated.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
1 file changed