Disable old @fastmath macro; implement new one that rewrites expressi…

…ons instead

base/base.jl

@@ -237,20 +237,38 @@ macro inbounds(blk)
     :(@boundscheck false $(esc(blk)))
 end
 
-macro fastmathmode(yesno,blk)
-    # hack: use this syntax since it avoids introducing line numbers
-    :($(Expr(:fastmath,yesno));
-      r = $(esc(blk));
-      $(Expr(:fastmath,:pop));
-      r)
-end
-
-macro fastmath(blk)
-    :(@fastmathmode true $(esc(blk)))
+# macro fastmathmode(yesno,blk)
+#     # hack: use this syntax since it avoids introducing line numbers
+#     :($(Expr(:fastmath,yesno));
+#       r = $(esc(blk));
+#       $(Expr(:fastmath,:pop));
+#       r)
+# end
+# 
+# macro fastmath(blk)
+#     :(@fastmathmode true $(esc(blk)))
+# end
+# 
+# macro ieeemath(blk)
+#     :(@fastmathmode false $(esc(blk)))
+# end
+
+function make_fastmath(expr)
+    if isa(expr, Expr)
+        Expr(make_fastmath(expr.head), map(make_fastmath, expr.args)...)
+    elseif expr==:+; :add_fast
+    elseif expr==:-; :sub_fast
+    elseif expr==:*; :mul_fast
+    elseif expr==:/; :div_fast
+    elseif expr==:rem; :rem_fast
+    elseif expr==:mod; :mod_fast
+    elseif expr==:cmp; :cmp_fast
+    else expr
+    end
 end
 
-macro ieeemath(blk)
-    :(@fastmathmode false $(esc(blk)))
+macro fastmath(expr)
+    make_fastmath(esc(expr))
 end
 
 macro label(name::Symbol)

base/exports.jl

@@ -464,6 +464,15 @@ export
     √,
     ∛,
 
+# fast math
+    add_fast,
+    sub_fast,
+    mul_fast,
+    div_fast,
+    rem_fast,
+    mod_fast,
+    cmp_fast,
+
 # specfun
     airy,
     airyai,
@@ -1409,9 +1418,9 @@ export
     @deprecate,
     @boundscheck,
     @inbounds,
-    @fastmathmode,
+    # @fastmathmode,
     @fastmath,
-    @ieeemath,
+    # @ieeemath,
     @simd,
     @label,
     @goto,

base/float.jl

@@ -208,22 +208,33 @@ rem(x::Float32, y::Float32) = box(Float32,rem_float(unbox(Float32,x),unbox(Float
 rem(x::Float64, y::Float64) = box(Float64,rem_float(unbox(Float64,x),unbox(Float64,y)))
 
 # fast versions that may violate strict IEEE semantics
+# TODO: isnan_fast and friends
+for (op_fast, op) in ((:add_fast, :+), (:sub_fast, :-),
+                      (:mul_fast, :*), (:div_fast, :/),
+                      (:rem_fast, :rem), (:mod_fast, :mod),
+                      (:cmp_fast, :cmp))
+    @eval begin
+        # fall-back implementation for non-numeric types
+        ($op_fast)(xs...) = ($op)(xs...)
+        # type promotion
+        ($op_fast)(x::Number, y::Number, zs::Number...) =
+            ($op_fast)(promote(x,y,zs...)...)
+        # fall-back implementation that applies after promotion
+        ($op_fast){T<:Number}(x::T,ys::T...) = ($op)(x,ys...)
+    end
+end
 for T in (Float32, Float64)
     @eval begin
-        neg_fast(x::$T) = box($T,neg_float_fast(unbox($T,x)))
+        sub_fast(x::$T) = box($T,neg_float_fast(unbox($T,x)))
         add_fast(x::$T, y::$T) = box($T,add_float_fast(unbox($T,x),unbox($T,y)))
         sub_fast(x::$T, y::$T) = box($T,sub_float_fast(unbox($T,x),unbox($T,y)))
         mul_fast(x::$T, y::$T) = box($T,mul_float_fast(unbox($T,x),unbox($T,y)))
         div_fast(x::$T, y::$T) = box($T,div_float_fast(unbox($T,x),unbox($T,y)))
         rem_fast(x::$T, y::$T) = box($T,rem_float_fast(unbox($T,x),unbox($T,y)))
+        add_fast(x::$T, y::$T, zs::$T...) = add_fast(add_fast(x, y), zs...)
+        mul_fast(x::$T, y::$T, zs::$T...) = mul_fast(mul_fast(x, y), zs...)
     end
 end
-neg_fast(x) = -x
-add_fast(x,y) = x+y
-sub_fast(x,y) = x-y
-mul_fast(x,y) = x*y
-div_fast(x,y) = x/y
-rem_fast(x,y) = rem(x,y)
 
 cld{T<:FloatingPoint}(x::T, y::T) = -fld(-x,y)
 
@@ -238,6 +249,17 @@ function mod{T<:FloatingPoint}(x::T, y::T)
     end
 end
 
+function mod_fast{T<:FloatingPoint}(x::T, y::T)
+    r = rem_fast(x,y)
+    if r == 0
+        copysign(r,y)
+    elseif (r > 0) $ (y > 0)
+        r+y
+    else
+        r
+    end
+end
+
 
 ## floating point comparisons ##
 ==(x::Float32, y::Float32) = eq_float(unbox(Float32,x),unbox(Float32,y))
@@ -269,6 +291,9 @@ function cmp(x::FloatingPoint, y::Real)
     ifelse(x<y, -1, ifelse(x>y, 1, 0))
 end
 
+cmp_fast(x::Float32, y::Float32) = ifelse(x<y, -1, ifelse(x>y, 1, 0))
+cmp_fast(x::Float64, y::Float64) = ifelse(x<y, -1, ifelse(x>y, 1, 0))
+
 for Ti in (Int64,UInt64,Int128,UInt128)
     for Tf in (Float32,Float64)
         @eval begin