math: add benchmark for float32/float64 conversions

This CL adds benchmarks for float32/float64 conversions
for following functions:

- Abs
- Sqrt
- Round
- RoundToEven
- Floor
- Ceil
- Trunc

Update #75463

Change-Id: Idb57e2e28a0fb59321e480cd676115c6e540cf4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/734680
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: David Chase <drchase@google.com>

src/math/all_test.go

@@ -3336,9 +3336,10 @@ func TestFloat32Sqrt(t *testing.T) {
 // Storing the results in these variables prevents the compiler
 // from completely optimizing the benchmarked functions away.
 var (
-	GlobalI int
-	GlobalB bool
-	GlobalF float64
+	GlobalI   int
+	GlobalB   bool
+	GlobalF   float64
+	GlobalF32 float32
 )
 
 func BenchmarkAcos(b *testing.B) {
@@ -3413,6 +3414,14 @@ func BenchmarkCeil(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkCeil32(b *testing.B) {
+	var x, src float32 = 0.0, 0.5
+	for i := 0; i < b.N; i++ {
+		x = float32(Ceil(float64(src)))
+	}
+	GlobalF32 = x
+}
+
 var copysignNeg = -1.0
 
 func BenchmarkCopysign(b *testing.B) {
@@ -3512,6 +3521,7 @@ func BenchmarkExp2Go(b *testing.B) {
 }
 
 var absPos = .5
+var absPos32 float32 = .5
 
 func BenchmarkAbs(b *testing.B) {
 	x := 0.0
@@ -3522,6 +3532,15 @@ func BenchmarkAbs(b *testing.B) {
 
 }
 
+func BenchmarkAbs32(b *testing.B) {
+	var x float32 = 0.0
+	for i := 0; i < b.N; i++ {
+		x = float32(Abs(float64(absPos32)))
+	}
+	GlobalF32 = x
+
+}
+
 func BenchmarkDim(b *testing.B) {
 	x := 0.0
 	for i := 0; i < b.N; i++ {
@@ -3538,6 +3557,14 @@ func BenchmarkFloor(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkFloor32(b *testing.B) {
+	var x, src float32 = 0.0, .5
+	for i := 0; i < b.N; i++ {
+		x = float32(Floor(float64(src)))
+	}
+	GlobalF32 = x
+}
+
 func BenchmarkMax(b *testing.B) {
 	x := 0.0
 	for i := 0; i < b.N; i++ {
@@ -3749,6 +3776,7 @@ func BenchmarkPow10Neg(b *testing.B) {
 }
 
 var roundNeg = float64(-2.5)
+var roundNeg32 float32 = -2.5
 
 func BenchmarkRound(b *testing.B) {
 	x := 0.0
@@ -3758,6 +3786,14 @@ func BenchmarkRound(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkRound32(b *testing.B) {
+	var x float32 = 0.0
+	for i := 0; i < b.N; i++ {
+		x = float32(Round(float64(roundNeg32)))
+	}
+	GlobalF32 = x
+}
+
 func BenchmarkRoundToEven(b *testing.B) {
 	x := 0.0
 	for i := 0; i < b.N; i++ {
@@ -3766,6 +3802,14 @@ func BenchmarkRoundToEven(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkRoundToEven32(b *testing.B) {
+	var x float32 = 0.0
+	for i := 0; i < b.N; i++ {
+		x = float32(RoundToEven(float64(roundNeg32)))
+	}
+	GlobalF32 = x
+}
+
 func BenchmarkRemainder(b *testing.B) {
 	x := 0.0
 	for i := 0; i < b.N; i++ {
@@ -3827,6 +3871,14 @@ func BenchmarkSqrtLatency(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkSqrt32Latency(b *testing.B) {
+	var x float32 = 10.0
+	for i := 0; i < b.N; i++ {
+		x = float32(Sqrt(float64(x)))
+	}
+	GlobalF32 = x
+}
+
 func BenchmarkSqrtIndirectLatency(b *testing.B) {
 	x := 10.0
 	f := Sqrt
@@ -3889,6 +3941,14 @@ func BenchmarkTrunc(b *testing.B) {
 	GlobalF = x
 }
 
+func BenchmarkTrunc32(b *testing.B) {
+	var x, src float32 = 0.0, .5
+	for i := 0; i < b.N; i++ {
+		x = float32(Trunc(float64(src)))
+	}
+	GlobalF32 = x
+}
+
 func BenchmarkY0(b *testing.B) {
 	x := 0.0
 	for i := 0; i < b.N; i++ {