test/codegen: port math/bits.OnesCount tests to codegen

And remove them from ssa_test.

Change-Id: I3efac5fea529bb0efa2dae32124530482ba5058e
Reviewed-on: https://go-review.googlesource.com/98815
Reviewed-by: Keith Randall <khr@golang.org>

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

@@ -547,34 +547,6 @@ var linuxAMD64Tests = []*asmTest{
 		`,
 		pos: []string{"\tROLW\t\\$8,"},
 	},
-	{
-		fn: `
-		func pop1(x uint64) int {
-			return bits.OnesCount64(x)
-		}`,
-		pos: []string{"\tPOPCNTQ\t", "support_popcnt"},
-	},
-	{
-		fn: `
-		func pop2(x uint32) int {
-			return bits.OnesCount32(x)
-		}`,
-		pos: []string{"\tPOPCNTL\t", "support_popcnt"},
-	},
-	{
-		fn: `
-		func pop3(x uint16) int {
-			return bits.OnesCount16(x)
-		}`,
-		pos: []string{"\tPOPCNTL\t", "support_popcnt"},
-	},
-	{
-		fn: `
-		func pop4(x uint) int {
-			return bits.OnesCount(x)
-		}`,
-		pos: []string{"\tPOPCNTQ\t", "support_popcnt"},
-	},
 	// multiplication merging tests
 	{
 		fn: `
@@ -1492,30 +1464,6 @@ var linuxARM64Tests = []*asmTest{
 		`,
 		pos: []string{"TBZ"},
 	},
-	{
-		fn: `
-		func $(x uint64) int {
-			return bits.OnesCount64(x)
-		}
-		`,
-		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
-	},
-	{
-		fn: `
-		func $(x uint32) int {
-			return bits.OnesCount32(x)
-		}
-		`,
-		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
-	},
-	{
-		fn: `
-		func $(x uint16) int {
-			return bits.OnesCount16(x)
-		}
-		`,
-		pos: []string{"\tVCNT\t", "\tVUADDLV\t"},
-	},
 	// Load-combining tests.
 	{
 		fn: `

test/codegen/mathbits.go

@@ -96,6 +96,34 @@ func Len8(n uint8) int {
 	return bits.Len8(n)
 }
 
+// -------------------- //
+//    bits.OnesCount    //
+// -------------------- //
+
+func OnesCount(n uint) int {
+	//amd64:"POPCNTQ",".*support_popcnt"
+	//arm64:"VCNT","VUADDLV"
+	return bits.OnesCount(n)
+}
+
+func OnesCount64(n uint64) int {
+	//amd64:"POPCNTQ",".*support_popcnt"
+	//arm64:"VCNT","VUADDLV"
+	return bits.OnesCount64(n)
+}
+
+func OnesCount32(n uint32) int {
+	//amd64:"POPCNTL",".*support_popcnt"
+	//arm64:"VCNT","VUADDLV"
+	return bits.OnesCount32(n)
+}
+
+func OnesCount16(n uint16) int {
+	//amd64:"POPCNTL",".*support_popcnt"
+	//arm64:"VCNT","VUADDLV"
+	return bits.OnesCount16(n)
+}
+
 // ------------------------ //
 //    bits.TrailingZeros    //
 // ------------------------ //