[PATCH] D50004: [PowerPC] Emit xscpsgndp instead of xxlor when copying floating point scalar registers

[Hiroshi Inoue via Phabricator via llvm-commits]

inouehrs added a comment.

XSCPSGNDP has longer latency (6 cycles) than XXLOR (2 cycles) on POWER8 while it has higher throughput with the same latency on POWER9. So XXLOR is preferable for pre-P9.

Also, the two instructions have different behavior for a denormal input value in my understanding; XSCPSGNDP does normalization but XXLOR does not. Does this difference matter?


https://reviews.llvm.org/D50004