rustc: Remove f{32,64} % from the language

This commit removes the compiler support for floating point modulus operations,
as well as from the language. An implementation for this operator is now
required to be provided by libraries.

Floating point modulus is rarely used, doesn't exist in C, and is always lowered
to an fmod library call by LLVM, and LLVM is considering removing support
entirely.

Closes #12278

diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index a250c6c298ba526808551260075eba516a568034..fb48fded2a56536d1bcc94c798fea26405b6d49c 100644 (file)
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -4125,6 +4125,7 @@ pub fn is_binopable(cx: &ctxt, ty: t, op: ast::BinOp) -> bool {
     static opcat_eq: int = 5;
     static opcat_bit: int = 6;
     static opcat_logic: int = 7;
+    static opcat_mod: int = 8;
 
     fn opcat(op: ast::BinOp) -> int {
         match op {
@@ -4132,7 +4133,7 @@ fn opcat(op: ast::BinOp) -> int {
           ast::BiSub => opcat_sub,
           ast::BiMul => opcat_mult,
           ast::BiDiv => opcat_mult,
-          ast::BiRem => opcat_mult,
+          ast::BiRem => opcat_mod,
           ast::BiAnd => opcat_logic,
           ast::BiOr => opcat_logic,
           ast::BiBitXor => opcat_bit,
@@ -4168,14 +4169,14 @@ fn tycat(cx: &ctxt, ty: t) -> int {
     static f: bool = false;
 
     let tbl = [
-    //           +, -, *, shift, rel, ==, bit, logic
-    /*other*/   [f, f, f, f,     f,   f,  f,   f],
-    /*bool*/    [f, f, f, f,     t,   t,  t,   t],
-    /*char*/    [f, f, f, f,     t,   t,  f,   f],
-    /*int*/     [t, t, t, t,     t,   t,  t,   f],
-    /*float*/   [t, t, t, f,     t,   t,  f,   f],
-    /*bot*/     [t, t, t, t,     t,   t,  t,   t],
-    /*raw ptr*/ [f, f, f, f,     t,   t,  f,   f]];
+    //           +, -, *, shift, rel, ==, bit, logic, mod
+    /*other*/   [f, f, f, f,     f,   f,  f,   f,     f],
+    /*bool*/    [f, f, f, f,     t,   t,  t,   t,     f],
+    /*char*/    [f, f, f, f,     t,   t,  f,   f,     f],
+    /*int*/     [t, t, t, t,     t,   t,  t,   f,     t],
+    /*float*/   [t, t, t, f,     t,   t,  f,   f,     f],
+    /*bot*/     [t, t, t, t,     t,   t,  t,   t,     t],
+    /*raw ptr*/ [f, f, f, f,     t,   t,  f,   f,     f]];
 
     return tbl[tycat(cx, ty) as uint ][opcat(op) as uint];
 }

diff --git a/src/libstd/num/f32.rs b/src/libstd/num/f32.rs
index 7c5fe4ff274842c22687c30d22f4a4dcd9cdaffd..cf457763513c23de3b5b36e12437fc4090cbf3da 100644 (file)
--- a/src/libstd/num/f32.rs
+++ b/src/libstd/num/f32.rs
@@ -41,6 +41,7 @@ mod cmath {
         pub fn frexpf(n: c_float, value: &mut c_int) -> c_float;
         pub fn fmaxf(a: c_float, b: c_float) -> c_float;
         pub fn fminf(a: c_float, b: c_float) -> c_float;
+        pub fn fmodf(a: c_float, b: c_float) -> c_float;
         pub fn nextafterf(x: c_float, y: c_float) -> c_float;
         pub fn hypotf(x: c_float, y: c_float) -> c_float;
         pub fn ldexpf(x: c_float, n: c_int) -> c_float;
@@ -201,7 +202,9 @@ fn div(&self, other: &f32) -> f32 { *self / *other }
 #[cfg(not(test))]
 impl Rem<f32,f32> for f32 {
     #[inline]
-    fn rem(&self, other: &f32) -> f32 { *self % *other }
+    fn rem(&self, other: &f32) -> f32 {
+        unsafe { cmath::fmodf(*self, *other) }
+    }
 }
 
 #[cfg(not(test))]

diff --git a/src/libstd/num/f64.rs b/src/libstd/num/f64.rs
index 69328a5ecdc111f6d9417f55db533514eb609379..4a751988d3655ec48ecfc24a40e9bb48450b330a 100644 (file)
--- a/src/libstd/num/f64.rs
+++ b/src/libstd/num/f64.rs
@@ -40,6 +40,7 @@ mod cmath {
         pub fn fdim(a: c_double, b: c_double) -> c_double;
         pub fn fmax(a: c_double, b: c_double) -> c_double;
         pub fn fmin(a: c_double, b: c_double) -> c_double;
+        pub fn fmod(a: c_double, b: c_double) -> c_double;
         pub fn nextafter(x: c_double, y: c_double) -> c_double;
         pub fn frexp(n: c_double, value: &mut c_int) -> c_double;
         pub fn hypot(x: c_double, y: c_double) -> c_double;
@@ -210,7 +211,9 @@ fn div(&self, other: &f64) -> f64 { *self / *other }
 #[cfg(not(test))]
 impl Rem<f64,f64> for f64 {
     #[inline]
-    fn rem(&self, other: &f64) -> f64 { *self % *other }
+    fn rem(&self, other: &f64) -> f64 {
+        unsafe { cmath::fmod(*self, *other) }
+    }
 }
 #[cfg(not(test))]
 impl Neg<f64> for f64 {