cmd/8g: extend elimination of temporaries to SSE2 code.
Before:
(erf.go:188) TEXT Erf+0(SB),$220
(erf.go:265) TEXT Erfc+0(SB),$204
(lgamma.go:174) TEXT Lgamma+0(SB),$948
After:
(erf.go:188) TEXT Erf+0(SB),$84
(erf.go:265) TEXT Erfc+0(SB),$84
(lgamma.go:174) TEXT Lgamma+0(SB),$44
SSE before vs. SSE after:
benchmark old ns/op new ns/op delta
BenchmarkAcosh 81 49 -39.14%
BenchmarkAsinh 109 109 +0.00%
BenchmarkAtanh 73 74 +0.68%
BenchmarkLgamma 138 42 -69.20%
BenchmarkModf 24 15 -36.95%
BenchmarkSqrtGo 565 556 -1.59%
R=rsc
CC=golang-dev
https://golang.org/cl/
7028048