perf: r1cs solver 40% faster by avoiding redudnant check

go.mod

@@ -4,7 +4,7 @@ go 1.17
 
 require (
 	github.com/consensys/bavard v0.1.8-0.20210915155054-088da2f7f54a
-	github.com/consensys/gnark-crypto v0.6.1-0.20220110145513-493bb1c180d9
+	github.com/consensys/gnark-crypto v0.6.1-0.20220201194429-65e05ef70dbb
 	github.com/fxamacker/cbor/v2 v2.2.0
 	github.com/leanovate/gopter v0.2.9
 	github.com/stretchr/testify v1.7.0
@@ -14,6 +14,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/kr/pretty v0.2.0 // indirect
 	github.com/mmcloughlin/addchain v0.4.0 // indirect
+	github.com/pkg/profile v1.6.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2 // indirect

go.sum

@@ -2,6 +2,8 @@ github.com/consensys/bavard v0.1.8-0.20210915155054-088da2f7f54a h1:AEpwbXTjBGKo
 github.com/consensys/bavard v0.1.8-0.20210915155054-088da2f7f54a/go.mod h1:9ItSMtA/dXMAiL7BG6bqW2m3NdSEObYWoH223nGHukI=
 github.com/consensys/gnark-crypto v0.6.1-0.20220110145513-493bb1c180d9 h1:NSmw/VuOS3KCClXAijCQ6dJVtCSMbTwK/M8ulvPCvmY=
 github.com/consensys/gnark-crypto v0.6.1-0.20220110145513-493bb1c180d9/go.mod h1:PicAZJP763+7N9LZFfj+MquTXq98pwjD6l8Ry8WdHSU=
+github.com/consensys/gnark-crypto v0.6.1-0.20220201194429-65e05ef70dbb h1:ymDzdskY9PUfh5eYzKUpttrydLVposO9BpMYAvrFk9E=
+github.com/consensys/gnark-crypto v0.6.1-0.20220201194429-65e05ef70dbb/go.mod h1:PicAZJP763+7N9LZFfj+MquTXq98pwjD6l8Ry8WdHSU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -18,6 +20,8 @@ github.com/leanovate/gopter v0.2.9/go.mod h1:U2L/78B+KVFIx2VmW6onHJQzXtFb+p5y3y2
 github.com/mmcloughlin/addchain v0.4.0 h1:SobOdjm2xLj1KkXN5/n0xTIWyZA2+s99UCY1iPfkHRY=
 github.com/mmcloughlin/addchain v0.4.0/go.mod h1:A86O+tHqZLMNO4w6ZZ4FlVQEadcoqkyU72HC5wJ4RlU=
 github.com/mmcloughlin/profile v0.1.1/go.mod h1:IhHD7q1ooxgwTgjxQYkACGA77oFTDdFVejUS1/tS/qU=
+github.com/pkg/profile v1.6.0 h1:hUDfIISABYI59DyeB3OTay/HxSRwTQ8rB/H83k6r5dM=
+github.com/pkg/profile v1.6.0/go.mod h1:qBsxPvzyUincmltOk6iyRVxHYg4adc0OFOv72ZdLa18=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=