[dev.ssa] cmd/compile: MOVBconst might also clobber flags
[dev.ssa] cmd/compile: MOVBconst might also clobber flags

It gets rewritten to an xor by the linker also.

Change-Id: Iae35130325d41bd1a09b7e971190cae6f4e17fac
Reviewed-on: https://go-review.googlesource.com/20058
Reviewed-by: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
Run-TryBot: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

momchil-velikov/go,Cofyc/go,4ad/go,derekmarcotte/go,derekmarcotte/go,miolini/go,suncycheng/go,vsekhar/elastic-go,derekmarcotte/go,codestation/go,miolini/go,4ad/go,goodlang/good,nawawi/go,4ad/go,ImJasonH/go,polyverse-security/go,miolini/go,linux-on-ibm-z/go,theif519/go,nawawi/go,cloudflare/go,polyverse-security/go,nawawi/go,suncycheng/go,golang/go,mwhudson/go,vanloswang/go,akutz/go,vsekhar/elastic-go,vsekhar/elastic-go,derekmarcotte/go,derekmarcotte/go,cloudflare/go,4ad/go,polyverse-security/go,ganboing/go-esx,Samurais/go,vanloswang/go,golang/go,goodlang/good,josharian/go,josharian/go,Samurais/go,miolini/go,miolini/go,CAFxX/go,golang/go,theif519/go,golang/go,binarycrusader/go,theif519/go,linux-on-ibm-z/go,CAFxX/go,binarycrusader/go,akutz/go,akutz/go,binarycrusader/go,vsekhar/elastic-go,Samurais/go,akutz/go,goodlang/good,momchil-velikov/go,mwhudson/go,polyverse-security/go,momchil-velikov/go,miolini/go,ganboing/go-esx,theif519/go,linux-on-ibm-z/go,golang/go,ganboing/go-esx,vanloswang/go,momchil-velikov/go,Cofyc/go,vanloswang/go,CAFxX/go,ImJasonH/go,4ad/go,linux-on-ibm-z/go,goodlang/good,golang/go,ganboing/go-esx,Samurais/go,akutz/go,Cofyc/go,derekmarcotte/go,mwhudson/go,binarycrusader/go,nawawi/go,josharian/go,polyverse-security/go,binarycrusader/go,CAFxX/go,nawawi/go,codestation/go,codestation/go,goodlang/good,suncycheng/go,codestation/go,suncycheng/go,linux-on-ibm-z/go,polyverse-security/go,golang/go,momchil-velikov/go,akutz/go,akutz/go,codestation/go,vanloswang/go,Cofyc/go,nawawi/go,ganboing/go-esx,codestation/go,cloudflare/go,josharian/go,ganboing/go-esx,mwhudson/go,codestation/go,Cofyc/go,suncycheng/go,Samurais/go,CAFxX/go,goodlang/good,Cofyc/go,mwhudson/go,christopher-henderson/Go,vanloswang/go,momchil-velikov/go,momchil-velikov/go,CAFxX/go,cloudflare/go,vsekhar/elastic-go,theif519/go,josharian/go,theif519/go,4ad/go,josharian/go,suncycheng/go,theif519/go,ganboing/go-esx,goodlang/good,4ad/go,binarycrusader/go,binarycrusader/go,ImJasonH/go,ImJasonH/go,derekmarcotte/go,binarycrusader/go,miolini/go,derekmarcotte/go,polyverse-security/go,suncycheng/go,Samurais/go,ImJasonH/go,cloudflare/go,Cofyc/go,codestation/go,ImJasonH/go,linux-on-ibm-z/go,josharian/go,vanloswang/go,mwhudson/go,goodlang/good,ImJasonH/go,Samurais/go,suncycheng/go,nawawi/go,ganboing/go-esx,mwhudson/go,theif519/go,vsekhar/elastic-go,linux-on-ibm-z/go,polyverse-security/go,josharian/go,Cofyc/go,nawawi/go,Samurais/go,vanloswang/go,miolini/go,vsekhar/elastic-go,momchil-velikov/go,cloudflare/go,CAFxX/go,4ad/go,cloudflare/go,CAFxX/go,akutz/go,golang/go,cloudflare/go,ImJasonH/go,mwhudson/go,linux-on-ibm-z/go,vsekhar/elastic-go