This way, the names of the tablegen defs match the names of the associated ISD nodes.
Hal, I saw you named frnd this way intentionally, because fround was already taken. Do you think renaming fround to fpround will cause more trouble than it's worth?
This will break out-of-tree backends, but it should not break them silently - the type constraints on the old fround and new fround are different, so patterns using the old fround will not compile with the new one.
Note that the confusion is not theoretical. :-) jlebar and I spent some time staring at a broken pattern until we had the "oh, this should be an *frnd*" realization.