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, 7 insertions, 0 deletions

diff --git a/test/codegen/math.go b/test/codegen/math.go
index aaf6b080ff..597271ce72 100644
--- a/test/codegen/math.go
+++ b/test/codegen/math.go
@@ -15,12 +15,14 @@ func approx(x float64) {
 	// arm64:"FRINTPD"
 	// ppc64:"FRIP"
 	// ppc64le:"FRIP"
+	// wasm:"F64Ceil"
 	sink64[0] = math.Ceil(x)
 
 	// s390x:"FIDBR\t[$]7"
 	// arm64:"FRINTMD"
 	// ppc64:"FRIM"
 	// ppc64le:"FRIM"
+	// wasm:"F64Floor"
 	sink64[1] = math.Floor(x)
 
 	// s390x:"FIDBR\t[$]1"
@@ -33,10 +35,12 @@ func approx(x float64) {
 	// arm64:"FRINTZD"
 	// ppc64:"FRIZ"
 	// ppc64le:"FRIZ"
+	// wasm:"F64Trunc"
 	sink64[3] = math.Trunc(x)
 
 	// s390x:"FIDBR\t[$]4"
 	// arm64:"FRINTND"
+	// wasm:"F64Nearest"
 	sink64[4] = math.RoundToEven(x)
 }
 
@@ -47,6 +51,7 @@ func sqrt(x float64) float64 {
 	// arm/7:"SQRTD"
 	// mips/hardfloat:"SQRTD" mips/softfloat:-"SQRTD"
 	// mips64/hardfloat:"SQRTD" mips64/softfloat:-"SQRTD"
+	// wasm:"F64Sqrt"
 	return math.Sqrt(x)
 }
 
@@ -57,6 +62,7 @@ func abs(x, y float64) {
 	// s390x:"LPDFR\t",-"MOVD\t"     (no integer load/store)
 	// ppc64:"FABS\t"
 	// ppc64le:"FABS\t"
+	// wasm:"F64Abs"
 	sink64[0] = math.Abs(x)
 
 	// amd64:"BTRQ\t[$]63","PXOR"    (TODO: this should be BTSQ)
@@ -78,6 +84,7 @@ func copysign(a, b, c float64) {
 	// s390x:"CPSDR",-"MOVD"         (no integer load/store)
 	// ppc64:"FCPSGN"
 	// ppc64le:"FCPSGN"
+	// wasm:"F64Copysign"
 	sink64[0] = math.Copysign(a, b)
 
 	// amd64:"BTSQ\t[$]63"