fix alloc for all cases

src/WithAlloc.jl

@@ -13,25 +13,56 @@ end
    map( a -> _bumper_alloc(a)[1], allocinfo )
 end
 
+# macro withalloc(ex)
+#    fncall = esc(ex.args[1])
+#    args = esc.(ex.args[2:end])
+#    quote
+#       # not sure why this isn't working ... 
+#       # whatalloc($fncall, $(args...))
+#       let 
+#          allocinfo = whatalloc($fncall, $(args...), )
+#          storobj = _bumper_alloc(allocinfo)
+#          $(fncall)(storobj..., $(args...), )
+#       end
+#    end
+# end
+
 macro withalloc(ex)
-   fncall = esc(ex.args[1])
-   args = esc.(ex.args[2:end])
+   esc_args = esc.(ex.args)
    quote
-      # not sure why this isn't working ... 
-      # whatalloc($fncall, $(args...))
-      let 
-         allocinfo = whatalloc($fncall, $(args...), )
-         storobj = _bumper_alloc(allocinfo)
-         $(fncall)(storobj..., $(args...), )
-      end
+      withalloc($(esc_args...))
    end
 end
 
 
-@inline function withalloc(fncall, args...) 
-   allocinfo = whatalloc(fncall, args..., )
-   storobj = _bumper_alloc(allocinfo)
-   fncall(storobj..., args..., )
+# For some reason that I don't understand the following implementation is allocating 
+# The @generated implementation below is to get around this. 
+# @inline function withalloc(fncall, args...) 
+#    allocinfo = whatalloc(fncall, args..., )
+#    storobj = _bumper_alloc(allocinfo)
+#    fncall(storobj..., args..., )
+# end 
+
+@inline function withalloc(fncall, args...)
+   allocinfo = whatalloc(fncall, args...)
+   _genwithalloc(allocinfo, fncall, args...) 
+end
+
+@inline @generated function _genwithalloc(allocinfo::TT, fncall, args...)  where {TT <: Tuple}
+   code = Expr[] 
+   LEN = length(TT.types) 
+   if TT.types[1] <: Tuple 
+      for i in 1:LEN
+         push!(code, Meta.parse("tmp$i = _bumper_alloc(allocinfo[$i])[1]"))
+      end
+   else 
+      push!(code, Meta.parse("tmp1 = _bumper_alloc(allocinfo)[1]"))
+      LEN = 1 
+   end
+   push!(code, Meta.parse("fncall($(join(["tmp$i, " for i in 1:LEN])) args...)"))
+   quote
+      $(code...)
+   end
 end 
 
 

test/test1.jl

@@ -109,13 +109,13 @@ nalloc2 = let
    B = randn(5,10); C = randn(10, 3); D = randn(10, 5)
    @allocated alloctest2(B, C, D)
 end
-@show nalloc2  # 64
+@test nalloc2 == 0
 
 nalloc2_nm = let    
    B = randn(5,10); C = randn(10, 3); D = randn(10, 5)
    @allocated alloctest2_nm(B, C, D)
 end
-@show nalloc2_nm  # 64
+@test nalloc2_nm == 0
 
 
 
@@ -164,6 +164,50 @@ nalloc3 = let
    @allocated alloctest2(B, C, D)
 end
 
-@show nalloc3   # 64
+@test nalloc3 == 0
 
 
+
+
+## Reproduce #1 
+
+using WithAlloc, LinearAlgebra, Bumper, BenchmarkTools 
+
+mymul2!(A1, A2, B, C, D) = mul!(A1, B, C), mul!(A2, B, D)
+
+function WithAlloc.whatalloc(::typeof(mymul2!), B, C, D) 
+   T1 = promote_type(eltype(B), eltype(C))
+   T2 = promote_type(eltype(B), eltype(D))
+   return ( (T1, size(B, 1), size(C, 2)), 
+            (T2, size(B, 1), size(D, 2)) )
+end
+
+function alloctest1(B, C, D) 
+   @no_escape begin 
+      a1, a2 = WithAlloc.whatalloc(mymul2!, B, C, D)
+      A1 = @alloc(a1...)
+      A2 = @alloc(a2...)
+      mymul2!(A1, A2, B, C, D) 
+      sum(A1) + sum(A2)
+   end
+end 
+
+function alloctest2(B, C, D) 
+   @no_escape begin 
+      A1, A2 = @withalloc mymul2!(B, C, D) 
+      sum(A1) + sum(A2)
+   end
+end 
+
+function alloctest3(B, C, D) 
+   @no_escape begin 
+      A1, A2 = WithAlloc.withalloc(mymul2!, B, C, D) 
+      sum(A1) + sum(A2)
+   end
+end 
+
+
+B = randn(5,10); C = randn(10, 3); D = randn(10, 5)
+@btime alloctest1($B, $C, $D)
+@btime alloctest2($B, $C, $D)
+@btime alloctest3($B, $C, $D)