math, math/bits: add intrinsics for wasm

This commit adds compiler intrinsics for the packages math and
math/bits on the wasm architecture for better performance.

benchmark                        old ns/op     new ns/op     delta
BenchmarkCeil                    8.31          3.21          -61.37%
BenchmarkCopysign                5.24          3.88          -25.95%
BenchmarkAbs                     5.42          3.34          -38.38%
BenchmarkFloor                   8.29          3.18          -61.64%
BenchmarkRoundToEven             9.76          3.26          -66.60%
BenchmarkSqrtLatency             8.13          4.88          -39.98%
BenchmarkSqrtPrime               5246          3535          -32.62%
BenchmarkTrunc                   8.29          3.15          -62.00%
BenchmarkLeadingZeros            13.0          4.23          -67.46%
BenchmarkLeadingZeros8           4.65          4.42          -4.95%
BenchmarkLeadingZeros16          7.60          4.38          -42.37%
BenchmarkLeadingZeros32          10.7          4.48          -58.13%
BenchmarkLeadingZeros64          12.9          4.31          -66.59%
BenchmarkTrailingZeros           6.52          4.04          -38.04%
BenchmarkTrailingZeros8          4.57          4.14          -9.41%
BenchmarkTrailingZeros16         6.69          4.16          -37.82%
BenchmarkTrailingZeros32         6.97          4.23          -39.31%
BenchmarkTrailingZeros64         6.59          4.00          -39.30%
BenchmarkOnesCount               7.93          3.30          -58.39%
BenchmarkOnesCount8              3.56          3.19          -10.39%
BenchmarkOnesCount16             4.85          3.19          -34.23%
BenchmarkOnesCount32             7.27          3.19          -56.12%
BenchmarkOnesCount64             8.08          3.28          -59.41%
BenchmarkRotateLeft              4.88          3.80          -22.13%
BenchmarkRotateLeft64            5.03          3.63          -27.83%

Change-Id: Ic1e0c2984878be8defb6eb7eb6ee63765c793222
Reviewed-on: https://go-review.googlesource.com/c/go/+/165177
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/test/codegen/mathbits.go b/test/codegen/mathbits.go
index c77b66c3f7..9a4051a0ce 100644
--- a/test/codegen/mathbits.go
+++ b/test/codegen/mathbits.go
@@ -17,6 +17,7 @@ func LeadingZeros(n uint) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.LeadingZeros(n)
 }
 
@@ -25,6 +26,7 @@ func LeadingZeros64(n uint64) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.LeadingZeros64(n)
 }
 
@@ -33,6 +35,7 @@ func LeadingZeros32(n uint32) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZW"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.LeadingZeros32(n)
 }
 
@@ -41,6 +44,7 @@ func LeadingZeros16(n uint16) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.LeadingZeros16(n)
 }
 
@@ -49,6 +53,7 @@ func LeadingZeros8(n uint8) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.LeadingZeros8(n)
 }
 
@@ -61,6 +66,7 @@ func Len(n uint) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.Len(n)
 }
 
@@ -69,6 +75,7 @@ func Len64(n uint64) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.Len64(n)
 }
 
@@ -77,6 +84,7 @@ func Len32(n uint32) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.Len32(n)
 }
 
@@ -85,6 +93,7 @@ func Len16(n uint16) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.Len16(n)
 }
 
@@ -93,6 +102,7 @@ func Len8(n uint8) int {
 	// s390x:"FLOGR"
 	// arm:"CLZ" arm64:"CLZ"
 	// mips:"CLZ"
+	// wasm:"I64Clz"
 	return bits.Len8(n)
 }
 
@@ -106,6 +116,7 @@ func OnesCount(n uint) int {
 	// s390x:"POPCNT"
 	// ppc64:"POPCNTD"
 	// ppc64le:"POPCNTD"
+	// wasm:"I64Popcnt"
 	return bits.OnesCount(n)
 }
 
@@ -115,6 +126,7 @@ func OnesCount64(n uint64) int {
 	// s390x:"POPCNT"
 	// ppc64:"POPCNTD"
 	// ppc64le:"POPCNTD"
+	// wasm:"I64Popcnt"
 	return bits.OnesCount64(n)
 }
 
@@ -124,6 +136,7 @@ func OnesCount32(n uint32) int {
 	// s390x:"POPCNT"
 	// ppc64:"POPCNTW"
 	// ppc64le:"POPCNTW"
+	// wasm:"I64Popcnt"
 	return bits.OnesCount32(n)
 }
 
@@ -133,6 +146,7 @@ func OnesCount16(n uint16) int {
 	// s390x:"POPCNT"
 	// ppc64:"POPCNTW"
 	// ppc64le:"POPCNTW"
+	// wasm:"I64Popcnt"
 	return bits.OnesCount16(n)
 }
 
@@ -140,6 +154,7 @@ func OnesCount8(n uint8) int {
 	// s390x:"POPCNT"
 	// ppc64:"POPCNTB"
 	// ppc64le:"POPCNTB"
+	// wasm:"I64Popcnt"
 	return bits.OnesCount8(n)
 }
 
@@ -187,6 +202,7 @@ func RotateLeft64(n uint64) uint64 {
 	// ppc64:"ROTL"
 	// ppc64le:"ROTL"
 	// s390x:"RLLG"
+	// wasm:"I64Rotl"
 	return bits.RotateLeft64(n, 37)
 }
 
@@ -246,6 +262,7 @@ func TrailingZeros(n uint) int {
 	// s390x:"FLOGR"
 	// ppc64:"ANDN","POPCNTD"
 	// ppc64le:"ANDN","POPCNTD"
+	// wasm:"I64Ctz"
 	return bits.TrailingZeros(n)
 }
 
@@ -255,6 +272,7 @@ func TrailingZeros64(n uint64) int {
 	// s390x:"FLOGR"
 	// ppc64:"ANDN","POPCNTD"
 	// ppc64le:"ANDN","POPCNTD"
+	// wasm:"I64Ctz"
 	return bits.TrailingZeros64(n)
 }
 
@@ -264,6 +282,7 @@ func TrailingZeros32(n uint32) int {
 	// s390x:"FLOGR","MOVWZ"
 	// ppc64:"ANDN","POPCNTW"
 	// ppc64le:"ANDN","POPCNTW"
+	// wasm:"I64Ctz"
 	return bits.TrailingZeros32(n)
 }
 
@@ -273,6 +292,7 @@ func TrailingZeros16(n uint16) int {
 	// s390x:"FLOGR","OR\t\\$65536"
 	// ppc64:"POPCNTD","OR\\t\\$65536"
 	// ppc64le:"POPCNTD","OR\\t\\$65536"
+	// wasm:"I64Ctz"
 	return bits.TrailingZeros16(n)
 }
 
@@ -280,6 +300,7 @@ func TrailingZeros8(n uint8) int {
 	// amd64:"BSFL","BTSL\\t\\$8"
 	// arm64:"ORR\t\\$256","RBITW","CLZW",-"MOVBU\tR",-"RBIT\t",-"CLZ\t"
 	// s390x:"FLOGR","OR\t\\$256"
+	// wasm:"I64Ctz"
 	return bits.TrailingZeros8(n)
 }