small optimizer improvements to tupleref_elim_pass and effect_free

improved versions of some tuple functions

Author: JeffBezanson

base/inference.jl

@@ -1851,7 +1851,7 @@ end
 # cannot be affected by previous calls, except assignment nodes
 function effect_free(e::ANY, sv, allow_volatile::Bool)
     if isa(e,Symbol) || isa(e,SymbolNode) || isa(e,Number) || isa(e,String) ||
-        isa(e,TopNode) || isa(e,QuoteNode) || isa(e,Type)
+        isa(e,TopNode) || isa(e,QuoteNode) || isa(e,Type) || isa(e,Tuple)
         return true
     end
     if isa(e,Expr)
@@ -2642,20 +2642,24 @@ function tupleref_elim_pass(e::Expr, sv)
         if isa(ei,Expr)
             tupleref_elim_pass(ei, sv)
             if is_known_call(ei, tupleref, sv) && length(ei.args)==3 &&
-                isa(ei.args[2],Expr) && isa(ei.args[3],Int)
+                isa(ei.args[3],Int)
                 e1 = ei.args[2]
                 j = ei.args[3]
-                if is_known_call(e1, tuple, sv) && (1 <= j < length(e1.args))
-                    ok = true
-                    for k = 2:length(e1.args)
-                        k == j+1 && continue
-                        if !effect_free(e1.args[k], sv, true)
-                            ok = false; break
+                if isa(e1,Expr)
+                    if is_known_call(e1, tuple, sv) && (1 <= j < length(e1.args))
+                        ok = true
+                        for k = 2:length(e1.args)
+                            k == j+1 && continue
+                            if !effect_free(e1.args[k], sv, true)
+                                ok = false; break
+                            end
+                        end
+                        if ok
+                            e.args[i] = e1.args[j+1]
                         end
                     end
-                    if ok
-                        e.args[i] = e1.args[j+1]
-                    end
+                elseif isa(e1,Tuple) && (1 <= j <= length(e1))
+                    e.args[i] = e1[j]
                 end
             end
         end

base/tuple.jl

@@ -36,6 +36,9 @@ ntuple(f::Function, n::Integer) =
     n==5 ? (f(1),f(2),f(3),f(4),f(5),) :
     tuple(ntuple(n-2,f)..., f(n-1), f(n))
 
+argtail(x, rest...) = rest
+tail(x::Tuple) = argtail(x...)
+
 # 0 argument function
 map(f::Callable) = f()
 # 1 argument function
@@ -44,7 +47,7 @@ map(f::Callable, t::(Any,))               = (f(t[1]),)
 map(f::Callable, t::(Any, Any))           = (f(t[1]), f(t[2]))
 map(f::Callable, t::(Any, Any, Any))      = (f(t[1]), f(t[2]), f(t[3]))
 map(f::Callable, t::(Any, Any, Any, Any)) = (f(t[1]), f(t[2]), f(t[3]), f(t[4]))
-map(f::Callable, t::Tuple)                = tuple([f(ti) for ti in t]...)
+map(f::Callable, t::Tuple)                = tuple(f(t[1]), map(f,tail(t))...)
 # 2 argument function
 map(f::Callable, t::(),        s::())        = ()
 map(f::Callable, t::(Any,),    s::(Any,))    = (f(t[1],s[1]),)
@@ -108,7 +111,10 @@ end
 isempty(x::()) = true
 isempty(x::Tuple) = false
 
-reverse(x::Tuple) = (n=length(x); tuple([x[n-k+1] for k=1:n]...))
+revargs() = ()
+revargs(x, r...) = tuple(revargs(r...)..., x)
+
+reverse(t::Tuple) = revargs(t...)
 
 ## specialized reduction ##