diff --git a/pkgs/development/libraries/fftw/default.nix b/pkgs/development/libraries/fftw/default.nix
index 2bcc1cd69a70..dfa4541e34b7 100644
--- a/pkgs/development/libraries/fftw/default.nix
+++ b/pkgs/development/libraries/fftw/default.nix
@@ -20,7 +20,8 @@ stdenv.mkDerivation rec {
     ]
     ++ optional (precision != "double") "--enable-${precision}"
     # all x86_64 have sse2
-    ++ optional stdenv.isx86_64 "--enable-sse2"
+    # however, not all float sizes fit
+    ++ optional (stdenv.isx86_64 && (precision == "single" || precision == "double") )  "--enable-sse2"
     ++ optional stdenv.cc.isGNU "--enable-openmp";
 
   enableParallelBuilding = true;
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index dd7e4691f406..2366ac4a35ec 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -6318,6 +6318,7 @@ let
   fftw = callPackage ../development/libraries/fftw { };
   fftwSinglePrec = fftw.override { precision = "single"; };
   fftwFloat = fftwSinglePrec; # the configure option is just an alias
+  fftwLongDouble = fftw.override { precision = "long-double"; };
 
   filter-audio = callPackage ../development/libraries/filter-audio {};