diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright © 2011, Liyang HU <fast-math@liyang.hu>
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Liyang HU nor the names of other contributors
+      may be used to endorse or promote products derived from this
+      software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Numeric/FastMath.hs b/Numeric/FastMath.hs
new file mode 100644
--- /dev/null
+++ b/Numeric/FastMath.hs
@@ -0,0 +1,25 @@
+-- | Compile-time optimisations for 'Float' and 'Double' that break IEEE-754
+-- compatibility.
+--
+-- Namely, this otherwise empty module contains RULES that rewrite @x-x@,
+-- @x*0@ and @0*x@ to @0@, which is incorrect (according to IEEE-754) when
+-- @x@ is @NaN@.
+--
+-- At the time of writing, @base-4.3.1.0:GHC/Base.lhs@ erroneously includes
+-- these rules for 'Float's, but not for 'Double's. This has been reported
+-- as GHC bug #5178: <http://hackage.haskell.org/trac/ghc/ticket/5178>.
+
+module Numeric.FastMath () where
+
+import GHC.Exts
+
+{-# RULES
+"minusFloat x x"    forall x#. minusFloat#  x#   x#   = 0.0#
+"timesFloat x 0.0"  forall x#. timesFloat#  x#   0.0# = 0.0#
+"timesFloat 0.0 x"  forall x#. timesFloat#  0.0# x#   = 0.0#
+
+"minusDouble x x"    forall x#. (-##) x#    x#    = 0.0##
+"timesDouble 0.0 x"  forall x#. (*##) 0.0## x#    = 0.0##
+"timesDouble x 0.0"  forall x#. (*##) x#    0.0## = 0.0##
+  #-}
+
diff --git a/Numeric/FastMath/Infinitesimal.hs b/Numeric/FastMath/Infinitesimal.hs
new file mode 100644
--- /dev/null
+++ b/Numeric/FastMath/Infinitesimal.hs
@@ -0,0 +1,11 @@
+-- | Also rewrite @0/x@ to @+0@, which should really be @-0@ for negative @x@.
+
+module Numeric.FastMath.Infinitesimal () where
+
+import GHC.Exts
+
+{-# RULES
+"divideFloat 0.0 x" forall x#. divideFloat# 0.0# x#   = 0.0#
+"divideDouble 0.0 x" forall x#. (/##) 0.0## x#    = 0.0##
+  #-}
+
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/fast-math.cabal b/fast-math.cabal
new file mode 100644
--- /dev/null
+++ b/fast-math.cabal
@@ -0,0 +1,34 @@
+name:           fast-math
+version:        0.1
+synopsis:       Non IEEE-754 compliant compile-time floating-point optimisations
+description:
+    The "Numeric.FastMath" module brings into scope RULES for 'Float's and
+    'Double's that rewrite @x-x@, @0*x@ and @x*0@ to @0@. This disagrees
+    with IEEE-754 when @x@ is @NaN@, but is acceptable for most
+    applications.
+    .
+    Importing "Numeric.FastMath.Infinitesimal" also rewrites @0/x@ to @0@.
+    .
+    Optimisation (at least @-O1@) must be enabled for any RULES to take effect.
+license:        BSD3
+license-file:   LICENSE
+author:         Liyang HU
+maintainer:     fast-math@liyang.hu
+copyright:      © 2011, Liyang HU
+category:       Math, Numeric
+build-type:     Simple
+cabal-version:  >= 1.2.3
+
+library
+    build-depends:
+        base >= 3 && < 5
+    exposed-modules:
+        Numeric.FastMath
+        Numeric.FastMath.Infinitesimal
+    extensions:
+        NoImplicitPrelude
+        MagicHash
+    ghc-options: -Wall -fno-warn-orphans
+
+-- vim: et ts=4 sw=4:
+