cmd/compile: support float min/max instructions on PPC64

This enables efficient use of the builtin min/max function
for float64 and float32 types on GOPPC64 >= power9.

Extend the assembler to support xsminjdp/xsmaxjdp and use
them to implement float min/max.

Simplify the VSX xx3 opcode rules to allow FPR arguments,
if all arguments are an FPR.

Change-Id: I15882a4ce5dc46eba71d683cf1d184dc4236a328
Reviewed-on: https://go-review.googlesource.com/c/go/+/574535
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Than McIntosh <thanm@google.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/test/codegen/floats.go b/test/codegen/floats.go
index 54dc87ecfd..d5c5475567 100644
--- a/test/codegen/floats.go
+++ b/test/codegen/floats.go
@@ -165,6 +165,8 @@ func Float64Min(a, b float64) float64 {
 	// amd64:"MINSD"
 	// arm64:"FMIND"
 	// riscv64:"FMIN"
+	// ppc64/power9:"XSMINJDP"
+	// ppc64/power10:"XSMINJDP"
 	return min(a, b)
 }
 
@@ -172,6 +174,8 @@ func Float64Max(a, b float64) float64 {
 	// amd64:"MINSD"
 	// arm64:"FMAXD"
 	// riscv64:"FMAX"
+	// ppc64/power9:"XSMAXJDP"
+	// ppc64/power10:"XSMAXJDP"
 	return max(a, b)
 }
 
@@ -179,6 +183,8 @@ func Float32Min(a, b float32) float32 {
 	// amd64:"MINSS"
 	// arm64:"FMINS"
 	// riscv64:"FMINS"
+	// ppc64/power9:"XSMINJDP"
+	// ppc64/power10:"XSMINJDP"
 	return min(a, b)
 }
 
@@ -186,5 +192,7 @@ func Float32Max(a, b float32) float32 {
 	// amd64:"MINSS"
 	// arm64:"FMAXS"
 	// riscv64:"FMAXS"
+	// ppc64/power9:"XSMAXJDP"
+	// ppc64/power10:"XSMAXJDP"
 	return max(a, b)
 }