[dev.ssa] cmd/compile/internal/ssa: add line numbers to Values

Change-Id: I1dfffd75cc1f49307c654f910f7133c03da6c84f
Reviewed-on: https://go-review.googlesource.com/10559
Reviewed-by: Keith Randall <khr@golang.org>

src/cmd/compile/internal/ssa/block.go

@@ -37,6 +37,9 @@ type Block struct {
 
 	// The containing function
 	Func *Func
+
+	// Line number for block's control operation
+	Line int32
 }
 
 //     kind           control    successors