gallivm: add a log function that handles edge cases

Same as log2_safe, which means that it can handle infs, 0s and
nans.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
2 files changed