cmd/compile: add math benchmarks

This adds benchmarks for division and modulus of 64 bit signed and unsigned
integers.

Updates #59089

Change-Id: Ie757c6d74a1f355873e79619eae26ece21a8f23e
Reviewed-on: https://go-review.googlesource.com/c/go/+/482656
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>

src/cmd/compile/internal/test/math_test.go

@@ -0,0 +1,167 @@
+package test
+
+import (
+	"testing"
+)
+
+var Output int
+
+func BenchmarkDiv64UnsignedSmall(b *testing.B) {
+	q := uint64(1)
+	for i := 1; i <= b.N; i++ {
+		q = (q + uint64(i)) / uint64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64Small(b *testing.B) {
+	q := int64(1)
+	for i := 1; i <= b.N; i++ {
+		q = (q + int64(i)) / int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64SmallNegDivisor(b *testing.B) {
+	q := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		q = (int64(i) - q) / -int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64SmallNegDividend(b *testing.B) {
+	q := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		q = -(int64(i) - q) / int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64SmallNegBoth(b *testing.B) {
+	q := int64(1)
+	for i := 1; i <= b.N; i++ {
+		q = -(int64(i) + q) / -int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64Unsigned(b *testing.B) {
+	q := uint64(1)
+	for i := 1; i <= b.N; i++ {
+		q = (uint64(0x7fffffffffffffff) - uint64(i) - (q & 1)) / uint64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64(b *testing.B) {
+	q := int64(1)
+	for i := 1; i <= b.N; i++ {
+		q = (int64(0x7fffffffffffffff) - int64(i) - (q & 1)) / int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64NegDivisor(b *testing.B) {
+	q := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		q = (int64(0x7fffffffffffffff) - int64(i) - (q & 1)) / -int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64NegDividend(b *testing.B) {
+	q := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		q = -(int64(0x7fffffffffffffff) - int64(i) - (q & 1)) / int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkDiv64NegBoth(b *testing.B) {
+	q := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		q = -(int64(0x7fffffffffffffff) - int64(i) - (q & 1)) / -int64(i)
+	}
+	Output = int(q)
+}
+
+func BenchmarkMod64UnsignedSmall(b *testing.B) {
+	r := uint64(1)
+	for i := 1; i <= b.N; i++ {
+		r = (uint64(i) + r) % uint64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64Small(b *testing.B) {
+	r := int64(1)
+	for i := 1; i <= b.N; i++ {
+		r = (int64(i) + r) % int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64SmallNegDivisor(b *testing.B) {
+	r := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		r = (int64(i) - r) % -int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64SmallNegDividend(b *testing.B) {
+	r := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		r = -(int64(i) - r) % int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64SmallNegBoth(b *testing.B) {
+	r := int64(1)
+	for i := 1; i <= b.N; i++ {
+		r = -(int64(i) + r) % -int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64Unsigned(b *testing.B) {
+	r := uint64(1)
+	for i := 1; i <= b.N; i++ {
+		r = (uint64(0x7fffffffffffffff) - uint64(i) - (r & 1)) % uint64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64(b *testing.B) {
+	r := int64(1)
+	for i := 1; i <= b.N; i++ {
+		r = (int64(0x7fffffffffffffff) - int64(i) - (r & 1)) % int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64NegDivisor(b *testing.B) {
+	r := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		r = (int64(0x7fffffffffffffff) - int64(i) - (r & 1)) % -int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64NegDividend(b *testing.B) {
+	r := int64(-1)
+	for i := 1; i <= b.N; i++ {
+		r = -(int64(0x7fffffffffffffff) - int64(i) - (r & 1)) % int64(i)
+	}
+	Output = int(r)
+}
+
+func BenchmarkMod64NegBoth(b *testing.B) {
+	r := int64(1)
+	for i := 1; i <= b.N; i++ {
+		r = -(int64(0x7fffffffffffffff) - int64(i) - (r & 1)) % -int64(i)
+	}
+	Output = int(r)
+}