cmd/compile: ignore dead phis in fuse
cmd/compile: ignore dead phis in fuse

Happens occasionally for boolean phis was used as a control.

Change-Id: Ie0f2483e9004c1706751d8dfb25ee2e5106d917e
Reviewed-on: https://go-review.googlesource.com/21310
Run-TryBot: Alexandru Moșoi <2d2dfcfad7b9832058fd41884a8955d042a85275@mosoi.ro>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@golang.org>

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