math: support to handle huge arguments in tan function on s390x

Currently on s390x, tan assembly implementation is not handling huge arguments at all. This change is to check for large arguments and revert back to native go implantation from assembly code in case of huge arguments.

The changes are implemented in assembly code to get better performance over native go implementation.

Benchmark details of tan function with table driven inputs are updated as part of the issue link.

Fixes #37854

Change-Id: I4e5321e65c27b7ce8c497fc9d3991ca8604753d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/470595
Reviewed-by: Keith Randall <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Run-TryBot: Keith Randall <[email protected]>

Author: Vishwanatha-HD

src/math/tan_s390x.s

@@ -49,10 +49,9 @@ TEXT	·tanAsm(SB), NOSPLIT, $0-16
 	FMOVD	F0, F2
 L2:
 	MOVD	$·tanxlim<>+0(SB), R1
-	WORD	$0xED201000	//cdb	%f2,0(%r1)
-	BYTE	$0x00
-	BYTE	$0x19
-	BGE	L11
+	FMOVD	0(R1), F1
+	FCMPU	F2, F1
+	BGT	L9
 	BVS	L11
 	MOVD	$·tanxadd<>+0(SB), R1
 	FMOVD	88(R5), F6
@@ -105,6 +104,8 @@ L11:
 L10:
 	WORD	$0xB3130020	//lcdbr	%f2,%f0
 	BR	L2
+L9:
+	BR	·tan(SB)
 atanIsZero:
 	FMOVD	F0, ret+8(FP)
 	RET