cmd/compile: intrinsify TrailingZeros16, OnesCount{8,16} for ppc64x

This change implements TrailingZeros16, OnesCount8 and OnesCount16
as intrinsics for ppc64x.

benchmark                       old ns/op     new ns/op     delta
BenchmarkTrailingZeros16-40     2.16          1.61          -25.46%

benchmark                   old ns/op     new ns/op     delta
BenchmarkOnesCount-40       0.71          0.71          +0.00%
BenchmarkOnesCount8-40      0.93          0.69          -25.81%
BenchmarkOnesCount16-40     1.54          0.75          -51.30%
BenchmarkOnesCount32-40     0.75          0.74          -1.33%
BenchmarkOnesCount64-40     0.71          0.71          +0.00%

Change-Id: I010fa9c0ef596a09362870d81193c633e70da637
Reviewed-on: https://go-review.googlesource.com/c/139137
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

src/cmd/compile/internal/gc/ssa.go

@@ -3236,7 +3236,7 @@ func init() {
 			y := s.newValue2(ssa.OpOr64, types.Types[TUINT64], x, c)
 			return s.newValue1(ssa.OpCtz64, types.Types[TINT], y)
 		},
-		sys.ARM64, sys.S390X)
+		sys.ARM64, sys.S390X, sys.PPC64)
 	addF("math/bits", "TrailingZeros8",
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			x := s.newValue1(ssa.OpZeroExt8to32, types.Types[TUINT32], args[0])
@@ -3427,12 +3427,12 @@ func init() {
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			return s.newValue1(ssa.OpPopCount16, types.Types[TINT], args[0])
 		},
-		sys.ARM64, sys.S390X)
+		sys.ARM64, sys.S390X, sys.PPC64)
 	addF("math/bits", "OnesCount8",
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			return s.newValue1(ssa.OpPopCount8, types.Types[TINT], args[0])
 		},
-		sys.S390X)
+		sys.S390X, sys.PPC64)
 	addF("math/bits", "OnesCount",
 		makeOnesCountAMD64(ssa.OpPopCount64, ssa.OpPopCount32),
 		sys.AMD64)

src/cmd/compile/internal/ssa/gen/PPC64.rules

@@ -297,14 +297,16 @@
 
 (Ctz64 x) -> (POPCNTD (ANDN <typ.Int64> (ADDconst <typ.Int64> [-1] x) x))
 (Ctz32 x) -> (POPCNTW (MOVWZreg (ANDN <typ.Int> (ADDconst <typ.Int> [-1] x) x)))
+(Ctz16 x) -> (POPCNTW (MOVHZreg (ANDN <typ.Int16> (ADDconst <typ.Int16> [-1] x) x)))
+(Ctz8 x) -> (POPCNTB (MOVBZreg (ANDN <typ.UInt8> (ADDconst <typ.UInt8> [-1] x) x)))
 
 (BitLen64 x) -> (SUB (MOVDconst [64]) (CNTLZD <typ.Int> x))
 (BitLen32 x) -> (SUB (MOVDconst [32]) (CNTLZW <typ.Int> x))
 
 (PopCount64 x) -> (POPCNTD x)
 (PopCount32 x) -> (POPCNTW (MOVWZreg x))
 (PopCount16 x) -> (POPCNTW (MOVHZreg x))
-(PopCount8 x) -> (POPCNTB (MOVBreg x))
+(PopCount8 x) -> (POPCNTB (MOVBZreg x))
 
 (And(64|32|16|8) x y) -> (AND x y)
 (Or(64|32|16|8) x y) -> (OR x y)