diff --git a/Cargo.toml b/Cargo.toml
index 48f6ee0..e086f7c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,13 +1,23 @@
 [package]
 authors = ["Jorge Aparicio <japaricious@gmail.com>"]
+build = "build.rs"
 name = "rustc_builtins"
 version = "0.1.0"
 
 [dependencies]
-rlibc = { git = "https://github.com/alexcrichton/rlibc", optional = true }
+
+[dependencies.rlibc]
+git = "https://github.com/alexcrichton/rlibc"
+optional = true
 
 [dev-dependencies]
 quickcheck = "0.3.1"
+rand = "0.3.14"
+
+[dev-dependencies.gcc_s]
+path = "gcc_s"
 
 [features]
 default = ["rlibc/weak"]
+
+[workspace]
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..298b656
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,7 @@
+use std::env;
+
+fn main() {
+    if env::var("TARGET").unwrap().ends_with("gnueabihf") {
+        println!("cargo:rustc-cfg=gnueabihf")
+    }
+}
diff --git a/gcc_s/Cargo.toml b/gcc_s/Cargo.toml
new file mode 100644
index 0000000..4e3080f
--- /dev/null
+++ b/gcc_s/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+authors = ["Jorge Aparicio <japaricious@gmail.com>"]
+name = "gcc_s"
+version = "0.1.0"
+
+[dependencies]
+libloading = "0.3.0"
diff --git a/gcc_s/src/lib.rs b/gcc_s/src/lib.rs
new file mode 100644
index 0000000..fa034b0
--- /dev/null
+++ b/gcc_s/src/lib.rs
@@ -0,0 +1,68 @@
+#![feature(drop_types_in_const)]
+
+extern crate libloading;
+
+use std::sync::{Once, ONCE_INIT};
+
+use libloading::Library;
+
+static mut GCC_S: Option<Library> = None;
+
+#[cfg(not(windows))]
+fn gcc_s() -> &'static Library {
+    #[cfg(not(target_os = "macos"))]
+    const LIBGCC_S: &'static str = "libgcc_s.so.1";
+
+    #[cfg(target_os = "macos")]
+    const LIBGCC_S: &'static str = "libgcc_s.1.dylib";
+
+    unsafe {
+        static INIT: Once = ONCE_INIT;
+
+        INIT.call_once(|| {
+            GCC_S = Some(Library::new(LIBGCC_S).unwrap());
+        });
+        GCC_S.as_ref().unwrap()
+    }
+}
+
+#[cfg(windows)]
+macro_rules! declare {
+    ($symbol:ident: fn($($i:ty),+) -> $o:ty) => {
+        pub fn $symbol() -> Option<unsafe extern fn($($i),+) -> $o> {
+            None
+        }
+    }
+}
+
+#[cfg(not(windows))]
+macro_rules! declare {
+    ($symbol:ident: fn($($i:ty),+) -> $o:ty) => {
+        pub fn $symbol() -> Option<unsafe extern fn($($i),+) -> $o> {
+            unsafe {
+                gcc_s().get(concat!("__", stringify!($symbol)).as_bytes()).ok().map(|s| *s)
+            }
+        }
+    }
+}
+
+declare!(ashldi3: fn(u64, u32) -> u64);
+declare!(ashrdi3: fn(i64, u32) -> i64);
+declare!(divdi3: fn(i64, i64) -> i64);
+declare!(divmoddi4: fn(i64, i64, &mut i64) -> i64);
+declare!(divmodsi4: fn(i32, i32, &mut i32) -> i32);
+declare!(divsi3: fn(i32, i32) -> i32);
+declare!(lshrdi3: fn(u64, u32) -> u64);
+declare!(moddi3: fn(i64, i64) -> i64);
+declare!(modsi3: fn(i32, i32) -> i32);
+declare!(muldi3: fn(u64, u64) -> u64);
+declare!(mulodi4: fn(i64, i64, &mut i32) -> i64);
+declare!(mulosi4: fn(i32, i32, &mut i32) -> i32);
+declare!(udivdi3: fn(u64, u64) -> u64);
+declare!(udivmoddi4: fn(u64, u64, Option<&mut u64>) -> u64);
+declare!(udivmodsi4: fn(u32, u32, Option<&mut u32>) -> u32);
+declare!(udivsi3: fn(u32, u32) -> u32);
+declare!(umoddi3: fn(u64, u64) -> u64);
+declare!(umodsi3: fn(u32, u32) -> u32);
+declare!(addsf3: fn(f32, f32) -> f32);
+declare!(adddf3: fn(f64, f64) -> f64);
diff --git a/src/float/add.rs b/src/float/add.rs
index 3ebc92b..14ff2f4 100644
--- a/src/float/add.rs
+++ b/src/float/add.rs
@@ -199,8 +199,12 @@ pub extern fn __aeabi_fadd(a: f32, b: f32) -> f32 {
 #[cfg(test)]
 mod tests {
     use core::{f32, f64};
-    use qc::{U32, U64};
+
     use float::Float;
+    use qc::{U32, U64};
+
+    use gcc_s;
+    use rand;
 
     // NOTE The tests below have special handing for NaN values.
     // Because NaN != NaN, the floating-point representations must be used
@@ -213,15 +217,30 @@ mod tests {
         fn addsf3(a: U32, b: U32) -> bool {
             let (a, b) = (f32::from_repr(a.0), f32::from_repr(b.0));
             let x = super::__addsf3(a, b);
-            let y = a + b;
-            x.eq_repr(y)
+
+            match gcc_s::addsf3() {
+                // NOTE(cfg) for some reason, on hard float targets, our implementation doesn't
+                // match the output of its gcc_s counterpart. Until we investigate further, we'll
+                // just avoid testing against gcc_s on those targets. Do note that our
+                // implementation matches the output of the FPU instruction on *hard* float targets
+                // and matches its gcc_s counterpart on *soft* float targets.
+                #[cfg(not(gnueabihf))]
+                Some(addsf3) if rand::random() => x.eq_repr(unsafe { addsf3(a, b) }),
+                _ => x.eq_repr(a + b),
+            }
         }
 
         fn adddf3(a: U64, b: U64) -> bool {
             let (a, b) = (f64::from_repr(a.0), f64::from_repr(b.0));
             let x = super::__adddf3(a, b);
-            let y = a + b;
-            x.eq_repr(y)
+
+            match gcc_s::adddf3() {
+                // NOTE(cfg) See NOTE above
+                #[cfg(not(gnueabihf))]
+                Some(adddf3) if rand::random() => x.eq_repr(unsafe { adddf3(a, b) }),
+                _ => x.eq_repr(a + b),
+
+            }
         }
     }
     
diff --git a/src/int/mul.rs b/src/int/mul.rs
index 3d68444..dea3499 100644
--- a/src/int/mul.rs
+++ b/src/int/mul.rs
@@ -74,11 +74,18 @@ mulo!(__mulodi4: i64);
 mod tests {
     use qc::{I32, I64, U64};
 
+    use gcc_s;
+    use rand;
+
     quickcheck! {
         fn muldi(a: U64, b: U64) -> bool {
             let (a, b) = (a.0, b.0);
             let r = super::__muldi3(a, b);
-            r == a.wrapping_mul(b)
+
+            match gcc_s::muldi3() {
+                Some(muldi3) if rand::random() => r == unsafe { muldi3(a, b) },
+                _ => r == a.wrapping_mul(b),
+            }
         }
 
         fn mulosi(a: I32, b: I32) -> bool {
@@ -88,7 +95,18 @@ mod tests {
             if overflow != 0 && overflow != 1 {
                 return false;
             }
-            (r, overflow != 0) == a.overflowing_mul(b)
+
+            match gcc_s::mulosi4() {
+                Some(mulosi4) if rand::random() => {
+                    let mut gcc_s_overflow = 2;
+                    let gcc_s_r = unsafe {
+                        mulosi4(a, b, &mut gcc_s_overflow)
+                    };
+
+                    (r, overflow) == (gcc_s_r, gcc_s_overflow)
+                },
+                _ => (r, overflow != 0) == a.overflowing_mul(b),
+            }
         }
 
         fn mulodi(a: I64, b: I64) -> bool {
@@ -98,7 +116,18 @@ mod tests {
             if overflow != 0 && overflow != 1 {
                 return false;
             }
-            (r, overflow != 0) == a.overflowing_mul(b)
+
+            match gcc_s::mulodi4() {
+                Some(mulodi4) if rand::random() => {
+                    let mut gcc_s_overflow = 2;
+                    let gcc_s_r = unsafe {
+                        mulodi4(a, b, &mut gcc_s_overflow)
+                    };
+
+                    (r, overflow) == (gcc_s_r, gcc_s_overflow)
+                },
+                _ => (r, overflow != 0) == a.overflowing_mul(b),
+            }
         }
     }
 }
diff --git a/src/int/sdiv.rs b/src/int/sdiv.rs
index 72ddbca..fcb9ed9 100644
--- a/src/int/sdiv.rs
+++ b/src/int/sdiv.rs
@@ -52,9 +52,12 @@ divmod!(__divmoddi4, __divdi3: i64);
 
 #[cfg(test)]
 mod tests {
-    use quickcheck::TestResult;
     use qc::{U32, U64};
 
+    use gcc_s;
+    use quickcheck::TestResult;
+    use rand;
+
     quickcheck!{
         fn divdi3(n: U64, d: U64) -> TestResult {
             let (n, d) = (n.0 as i64, d.0 as i64);
@@ -62,7 +65,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let q = super::__divdi3(n, d);
-                TestResult::from_bool(q == n / d)
+
+                match gcc_s::divdi3() {
+                    Some(divdi3) if rand::random() => {
+                        TestResult::from_bool(q == unsafe { divdi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(q == n / d),
+                }
             }
         }
 
@@ -72,7 +81,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__moddi3(n, d);
-                TestResult::from_bool(r == n % d)
+
+                match gcc_s::moddi3() {
+                    Some(moddi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { moddi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(r == n % d),
+                }
             }
         }
 
@@ -83,7 +98,18 @@ mod tests {
             } else {
                 let mut r = 0;
                 let q = super::__divmoddi4(n, d, &mut r);
-                TestResult::from_bool(q == n / d && r == n % d)
+
+                match gcc_s::divmoddi4() {
+                    Some(divmoddi4) if rand::random() => {
+                        let mut gcc_s_r = 0;
+                        let gcc_s_q = unsafe {
+                            divmoddi4(n, d, &mut gcc_s_r)
+                        };
+
+                        TestResult::from_bool(q == gcc_s_q && r == gcc_s_r)
+                    },
+                    _ => TestResult::from_bool(q == n / d && r == n % d),
+                }
             }
         }
 
@@ -93,7 +119,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let q = super::__divsi3(n, d);
-                TestResult::from_bool(q == n / d)
+
+                match gcc_s::divsi3() {
+                    Some(divsi3) if rand::random() => {
+                        TestResult::from_bool(q == unsafe { divsi3(n, d)})
+                    },
+                    _ => TestResult::from_bool(q == n / d),
+                }
             }
         }
 
@@ -103,7 +135,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__modsi3(n, d);
-                TestResult::from_bool(r == n % d)
+
+                match gcc_s::modsi3() {
+                    Some(modsi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { modsi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(r == n % d),
+                }
             }
         }
 
@@ -114,7 +152,18 @@ mod tests {
             } else {
                 let mut r = 0;
                 let q = super::__divmodsi4(n, d, &mut r);
-                TestResult::from_bool(q == n / d && r == n % d)
+
+                match gcc_s::divmodsi4() {
+                    Some(divmodsi4) if rand::random() => {
+                        let mut gcc_s_r = 0;
+                        let gcc_s_q = unsafe {
+                            divmodsi4(n, d, &mut gcc_s_r)
+                        };
+
+                        TestResult::from_bool(q == gcc_s_q && r == gcc_s_r)
+                    },
+                    _ => TestResult::from_bool(q == n / d && r == n % d),
+                }
             }
         }
     }
diff --git a/src/int/shift.rs b/src/int/shift.rs
index 96ae6db..bafc9db 100644
--- a/src/int/shift.rs
+++ b/src/int/shift.rs
@@ -60,9 +60,12 @@ lshr!(__lshrdi3: u64);
 
 #[cfg(test)]
 mod tests {
-    use quickcheck::TestResult;
     use qc::{I64, U64};
 
+    use gcc_s;
+    use quickcheck::TestResult;
+    use rand;
+
     // NOTE We purposefully stick to `u32` for `b` here because we want "small" values (b < 64)
     quickcheck! {
         fn ashldi(a: U64, b: u32) -> TestResult {
@@ -71,7 +74,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__ashldi3(a, b);
-                TestResult::from_bool(r == a << b)
+
+                match gcc_s::ashldi3() {
+                    Some(ashldi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { ashldi3(a, b) })
+                    },
+                    _ => TestResult::from_bool(r == a << b),
+                }
             }
         }
 
@@ -81,7 +90,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__ashrdi3(a, b);
-                TestResult::from_bool(r == a >> b)
+
+                match gcc_s::ashrdi3() {
+                    Some(ashrdi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { ashrdi3(a, b) })
+                    },
+                    _ => TestResult::from_bool(r == a >> b),
+                }
             }
         }
 
@@ -91,7 +106,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__lshrdi3(a, b);
-                TestResult::from_bool(r == a >> b)
+
+                match gcc_s::lshrdi3() {
+                    Some(lshrdi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { lshrdi3(a, b) })
+                    },
+                    _ => TestResult::from_bool(r == a >> b),
+                }
             }
         }
     }
diff --git a/src/int/udiv.rs b/src/int/udiv.rs
index f3ec720..89793c8 100644
--- a/src/int/udiv.rs
+++ b/src/int/udiv.rs
@@ -228,9 +228,12 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
 
 #[cfg(test)]
 mod tests {
-    use quickcheck::TestResult;
     use qc::{U32, U64};
 
+    use gcc_s;
+    use quickcheck::TestResult;
+    use rand;
+
     quickcheck!{
         fn udivdi3(n: U64, d: U64) -> TestResult {
             let (n, d) = (n.0, d.0);
@@ -238,7 +241,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let q = super::__udivdi3(n, d);
-                TestResult::from_bool(q == n / d)
+
+                match gcc_s::udivdi3() {
+                    Some(udivdi3) if rand::random() => {
+                        TestResult::from_bool(q == unsafe { udivdi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(q == n / d),
+                }
             }
         }
 
@@ -248,7 +257,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__umoddi3(n, d);
-                TestResult::from_bool(r == n % d)
+
+                match gcc_s::umoddi3() {
+                    Some(umoddi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { umoddi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(r == n % d),
+                }
             }
         }
 
@@ -259,7 +274,18 @@ mod tests {
             } else {
                 let mut r = 0;
                 let q = super::__udivmoddi4(n, d, Some(&mut r));
-                TestResult::from_bool(q == n / d && r == n % d)
+
+                match gcc_s::udivmoddi4() {
+                    Some(udivmoddi4) if rand::random() => {
+                        let mut gcc_s_r = 0;
+                        let gcc_s_q = unsafe {
+                            udivmoddi4(n, d, Some(&mut gcc_s_r))
+                        };
+
+                        TestResult::from_bool(q == gcc_s_q && r == gcc_s_r)
+                    },
+                    _ => TestResult::from_bool(q == n / d && r == n % d),
+                }
             }
         }
 
@@ -269,7 +295,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let q = super::__udivsi3(n, d);
-                TestResult::from_bool(q == n / d)
+
+                match gcc_s::udivsi3() {
+                    Some(udivsi3) if rand::random() => {
+                        TestResult::from_bool(q == unsafe { udivsi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(q == n / d),
+                }
             }
         }
 
@@ -279,7 +311,13 @@ mod tests {
                 TestResult::discard()
             } else {
                 let r = super::__umodsi3(n, d);
-                TestResult::from_bool(r == n % d)
+
+                match gcc_s::umodsi3() {
+                    Some(umodsi3) if rand::random() => {
+                        TestResult::from_bool(r == unsafe { umodsi3(n, d) })
+                    },
+                    _ => TestResult::from_bool(r == n % d),
+                }
             }
         }
 
@@ -290,7 +328,18 @@ mod tests {
             } else {
                 let mut r = 0;
                 let q = super::__udivmodsi4(n, d, Some(&mut r));
-                TestResult::from_bool(q == n / d && r == n % d)
+
+                match gcc_s::udivmodsi4() {
+                    Some(udivmodsi4) if rand::random() => {
+                        let mut gcc_s_r = 0;
+                        let gcc_s_q = unsafe {
+                            udivmodsi4(n, d, Some(&mut gcc_s_r))
+                        };
+
+                        TestResult::from_bool(q == gcc_s_q && r == gcc_s_r)
+                    },
+                    _ => TestResult::from_bool(q == n / d && r == n % d),
+                }
             }
         }
     }
diff --git a/src/lib.rs b/src/lib.rs
index 9efebcd..88bbbec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,6 +17,12 @@ extern crate quickcheck;
 #[cfg(test)]
 extern crate core;
 
+#[cfg(test)]
+extern crate gcc_s;
+
+#[cfg(test)]
+extern crate rand;
+
 #[cfg(all(not(windows), not(target_os = "macos")))]
 extern crate rlibc;