cmd/compile: add rules to emit SETBC/R instructions on power10
This CL adds rules that replaces instances of ISEL that produce
a boolean result based on a condition register by SETBC/SETBCR
operations. On Power10 these are convereted to SETBC/SETBCR
instructions that use one register instead of 3 registers
conventionally used by ISEL and hence reduces register pressure.
On loops written specifically to exercise such instances of ISEL
extensively, a performance improvement of 2.5% is seen on Power10.
Also added verification tests to verify correct generation of
SETBC/SETBCR instructions on Power10.
Change-Id: Ib719897f09d893de40324440a43052dca026e8fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/449795
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Archana Ravindar <aravind5@in.ibm.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>