[dev.ssa] cmd/compile/internal/ssa: Phi inputs from dead blocks are not live
[dev.ssa] cmd/compile/internal/ssa: Phi inputs from dead blocks are not live

Fixes #11676

Change-Id: I941f951633c89bb1454ce6d1d1b4124d46a7d9dd
Reviewed-on: https://go-review.googlesource.com/12091
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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