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What version of Go are you using (go version)?

go version devel +9fcbde7 Wed Sep 14 10:07:17 2016 -0500 linux/ppc64le

What operating system and processor architecture are you using (go env)?

Ubuntu 16.04 ppc64le

What did you do?

Built the test from the math package, then inspected the objdump.

What did you expect to see?

Looking for opportunities for improvement.

What did you see instead?

In main.main, this code is generated:
111c8: 1f 00 e0 3f lis r31,31
111cc: 98 29 9f e8 ld r4,10648(r31)
111d0: 1f 00 e0 3f lis r31,31
111d4: 90 29 bf e8 ld r5,10640(r31)
111d8: 1f 00 e0 3f lis r31,31
111dc: e0 29 df e8 ld r6,10720(r31)
111e0: 1f 00 e0 3f lis r31,31
111e4: d8 29 ff e8 ld r7,10712(r31)
111e8: 1f 00 e0 3f lis r31,31
111ec: d0 29 1f e9 ld r8,10704(r31)
111f0: 1f 00 e0 3f lis r31,31
111f4: a0 29 3f e9 ld r9,10656(r31)
111f8: 1f 00 e0 3f lis r31,31
111fc: b0 29 5f e9 ld r10,10672(r31)
11200: 1f 00 e0 3f lis r31,31
11204: b8 29 7f e9 ld r11,10680(r31)
11208: 1f 00 e0 3f lis r31,31
1120c: c0 29 9f e9 ld r12,10688(r31)

r31 is reloaded each time with the same value. I believe this happens because this is a MOVD based on SB which implicitly generates two instructions, and uses r31 for the temp register and possibly that is not visible to the register allocator.