a couple trait method call optimizations

src/libextra/num/bigint.rs

@@ -115,8 +115,8 @@ impl TotalOrd for BigUint {
         if s_len > o_len { return Greater;  }
 
         for (&self_i, &other_i) in self.data.rev_iter().zip(other.data.rev_iter()) {
-            cond!((self_i < other_i) { return Less; }
-                  (self_i > other_i) { return Greater; })
+            if self_i < other_i { return Less; }
+            if self_i > other_i { return Greater; }
         }
         return Equal;
     }

src/librustc/middle/trans/expr.rs

@@ -313,6 +313,36 @@ pub fn trans_to_datum(bcx: @mut Block, expr: @ast::Expr) -> DatumBlock {
         let target_obj_ty = expr_ty_adjusted(bcx, expr);
         debug!("auto_borrow_obj(target=%s)",
                target_obj_ty.repr(tcx));
+
+        // Extract source store information
+        let (source_store, source_mutbl) = match ty::get(source_datum.ty).sty {
+            ty::ty_trait(_, _, s, m, _) => (s, m),
+            _ => {
+                bcx.sess().span_bug(
+                    expr.span,
+                    fmt!("auto_borrow_trait_obj expected a trait, found %s",
+                         source_datum.ty.repr(bcx.tcx())));
+            }
+        };
+
+        // check if any borrowing is really needed or we could reuse the source_datum instead
+        match ty::get(target_obj_ty).sty {
+            ty::ty_trait(_, _, ty::RegionTraitStore(target_scope), target_mutbl, _) => {
+                if target_mutbl == ast::MutImmutable && target_mutbl == source_mutbl {
+                    match source_store {
+                        ty::RegionTraitStore(source_scope) => {
+                            if tcx.region_maps.is_subregion_of(target_scope, source_scope) {
+                                return DatumBlock { bcx: bcx, datum: source_datum };
+                            }
+                        },
+                        _ => {}
+
+                    };
+                }
+            },
+            _ => {}
+        }
+
         let scratch = scratch_datum(bcx, target_obj_ty,
                                     "__auto_borrow_obj", false);
 
@@ -331,15 +361,6 @@ pub fn trans_to_datum(bcx: @mut Block, expr: @ast::Expr) -> DatumBlock {
         // ~T, or &T, depending on source_obj_ty.
         let source_data_ptr = GEPi(bcx, source_llval, [0u, abi::trt_field_box]);
         let source_data = Load(bcx, source_data_ptr); // always a ptr
-        let (source_store, source_mutbl) = match ty::get(source_datum.ty).sty {
-            ty::ty_trait(_, _, s, m, _) => (s, m),
-            _ => {
-                bcx.sess().span_bug(
-                    expr.span,
-                    fmt!("auto_borrow_trait_obj expected a trait, found %s",
-                         source_datum.ty.repr(bcx.tcx())));
-            }
-        };
         let target_data = match source_store {
             ty::BoxTraitStore(*) => {
                 // For deref of @T or @mut T, create a dummy datum and

src/librustc/middle/trans/meth.rs

@@ -434,13 +434,22 @@ pub fn trans_trait_callee(bcx: @mut Block,
     let _icx = push_ctxt("impl::trans_trait_callee");
     let mut bcx = bcx;
 
+    // make a local copy for trait if needed
     let self_ty = expr_ty_adjusted(bcx, self_expr);
-    let self_scratch = scratch_datum(bcx, self_ty, "__trait_callee", false);
-    bcx = expr::trans_into(bcx, self_expr, expr::SaveIn(self_scratch.val));
+    let self_scratch = match ty::get(self_ty).sty {
+        ty::ty_trait(_, _, ty::RegionTraitStore(*), _, _) => {
+            unpack_datum!(bcx, expr::trans_to_datum(bcx, self_expr))
+        }
+        _ => {
+            let d = scratch_datum(bcx, self_ty, "__trait_callee", false);
+            bcx = expr::trans_into(bcx, self_expr, expr::SaveIn(d.val));
+            // Arrange a temporary cleanup for the object in case something
+            // should go wrong before the method is actually *invoked*.
+            d.add_clean(bcx);
+            d
+        }
+    };
 
-    // Arrange a temporary cleanup for the object in case something
-    // should go wrong before the method is actually *invoked*.
-    self_scratch.add_clean(bcx);
 
     let callee_ty = node_id_type(bcx, callee_id);
     trans_trait_callee_from_llval(bcx,

src/librustc/middle/trans/type_.rs

@@ -278,23 +278,12 @@ impl Type {
 
     pub fn opaque_trait(ctx: &CrateContext, store: ty::TraitStore) -> Type {
         let tydesc_ptr = ctx.tydesc_type.ptr_to();
-        match store {
-            ty::BoxTraitStore => {
-                Type::struct_(
-                    [ tydesc_ptr, Type::opaque_box(ctx).ptr_to() ],
-                false)
-            }
-            ty::UniqTraitStore => {
-                Type::struct_(
-                    [ tydesc_ptr, Type::unique(ctx, &Type::i8()).ptr_to()],
-                false)
-            }
-            ty::RegionTraitStore(*) => {
-                Type::struct_(
-                    [ tydesc_ptr, Type::i8().ptr_to() ],
-                false)
-            }
-        }
+        let box_ty = match store {
+            ty::BoxTraitStore => Type::opaque_box(ctx),
+            ty::UniqTraitStore => Type::unique(ctx, &Type::i8()),
+            ty::RegionTraitStore(*) => Type::i8()
+        };
+        Type::struct_([tydesc_ptr, box_ty.ptr_to()], false)
     }
 
     pub fn kind(&self) -> TypeKind {

src/libstd/borrow.rs

@@ -22,7 +22,7 @@ pub fn to_uint<T>(thing: &T) -> uint {
 /// Determine if two borrowed pointers point to the same thing.
 #[inline]
 pub fn ref_eq<'a, 'b, T>(thing: &'a T, other: &'b T) -> bool {
-    to_uint(thing) == to_uint(other)
+    (thing as *T) == (other as *T)
 }
 
 // Equality for region pointers
@@ -70,3 +70,17 @@ impl<'self, T: TotalEq> TotalEq for &'self T {
     #[inline]
     fn equals(&self, other: & &'self T) -> bool { (**self).equals(*other) }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::ref_eq;
+
+    #[test]
+    fn test_ref_eq() {
+        let x = 1;
+        let y = 1;
+
+        assert!(ref_eq(&x, &x));
+        assert!(!ref_eq(&x, &y));
+    }
+}

src/libstd/char.rs

@@ -281,11 +281,11 @@ pub fn escape_unicode(c: char, f: &fn(char)) {
     // avoid calling str::to_str_radix because we don't really need to allocate
     // here.
     f('\\');
-    let pad = cond!(
-        (c <= '\xff')   { f('x'); 2 }
-        (c <= '\uffff') { f('u'); 4 }
-        _               { f('U'); 8 }
-    );
+    let pad = match () {
+        _ if c <= '\xff'    => { f('x'); 2 }
+        _ if c <= '\uffff'  => { f('u'); 4 }
+        _                   => { f('U'); 8 }
+    };
     for offset in range_step::<i32>(4 * (pad - 1), -1, -4) {
         unsafe {
             match ((c as i32) >> offset) & 0xf {
@@ -329,13 +329,13 @@ pub fn len_utf8_bytes(c: char) -> uint {
     static MAX_FOUR_B:  uint = 2097152u;
 
     let code = c as uint;
-    cond!(
-        (code < MAX_ONE_B)   { 1u }
-        (code < MAX_TWO_B)   { 2u }
-        (code < MAX_THREE_B) { 3u }
-        (code < MAX_FOUR_B)  { 4u }
-        _ { fail!("invalid character!") }
-    )
+    match () {
+        _ if code < MAX_ONE_B   => 1u,
+        _ if code < MAX_TWO_B   => 2u,
+        _ if code < MAX_THREE_B => 3u,
+        _ if code < MAX_FOUR_B  => 4u,
+        _                       => fail!("invalid character!"),
+    }
 }
 
 impl ToStr for char {

src/libstd/num/f32.rs

@@ -206,35 +206,35 @@ impl Orderable for f32 {
     /// Returns `NaN` if either of the numbers are `NaN`.
     #[inline]
     fn min(&self, other: &f32) -> f32 {
-        cond!(
-            (self.is_NaN())  { *self  }
-            (other.is_NaN()) { *other }
-            (*self < *other) { *self  }
-            _                { *other }
-        )
+        match () {
+            _ if self.is_NaN()  => *self,
+            _ if other.is_NaN() => *other,
+            _ if *self < *other => *self,
+            _                   => *other,
+        }
     }
 
     /// Returns `NaN` if either of the numbers are `NaN`.
     #[inline]
     fn max(&self, other: &f32) -> f32 {
-        cond!(
-            (self.is_NaN())  { *self  }
-            (other.is_NaN()) { *other }
-            (*self > *other) { *self  }
-            _                { *other }
-        )
+        match () {
+            _ if self.is_NaN()  => *self,
+            _ if other.is_NaN() => *other,
+            _ if *self > *other => *self,
+            _                   => *other,
+        }
     }
 
     /// Returns the number constrained within the range `mn <= self <= mx`.
     /// If any of the numbers are `NaN` then `NaN` is returned.
     #[inline]
     fn clamp(&self, mn: &f32, mx: &f32) -> f32 {
-        cond!(
-            (self.is_NaN())   { *self }
-            (!(*self <= *mx)) { *mx   }
-            (!(*self >= *mn)) { *mn   }
-            _                 { *self }
-        )
+        match () {
+            _ if self.is_NaN()   => *self,
+            _ if !(*self <= *mx) => *mx,
+            _ if !(*self >= *mn) => *mn,
+            _                    => *self,
+        }
     }
 }
 

src/libstd/num/f64.rs

@@ -229,35 +229,35 @@ impl Orderable for f64 {
     /// Returns `NaN` if either of the numbers are `NaN`.
     #[inline]
     fn min(&self, other: &f64) -> f64 {
-        cond!(
-            (self.is_NaN())  { *self  }
-            (other.is_NaN()) { *other }
-            (*self < *other) { *self  }
-            _                { *other }
-        )
+        match () {
+            _ if self.is_NaN()  => *self,
+            _ if other.is_NaN() => *other,
+            _ if *self < *other => *self,
+            _                   => *other,
+        }
     }
 
     /// Returns `NaN` if either of the numbers are `NaN`.
     #[inline]
     fn max(&self, other: &f64) -> f64 {
-        cond!(
-            (self.is_NaN())  { *self  }
-            (other.is_NaN()) { *other }
-            (*self > *other) { *self  }
-            _                { *other }
-        )
+        match () {
+            _ if self.is_NaN()  => *self,
+            _ if other.is_NaN() => *other,
+            _ if *self > *other => *self,
+            _                   => *other,
+        }
     }
 
     /// Returns the number constrained within the range `mn <= self <= mx`.
     /// If any of the numbers are `NaN` then `NaN` is returned.
     #[inline]
     fn clamp(&self, mn: &f64, mx: &f64) -> f64 {
-        cond!(
-            (self.is_NaN())   { *self }
-            (!(*self <= *mx)) { *mx   }
-            (!(*self >= *mn)) { *mn   }
-            _                 { *self }
-        )
+        match () {
+            _ if self.is_NaN()   => *self,
+            _ if !(*self <= *mx) => *mx,
+            _ if !(*self >= *mn) => *mn,
+            _                    => *self,
+        }
     }
 }
 

src/libstd/num/uint_macros.rs

@@ -70,11 +70,11 @@ impl Orderable for $T {
     /// Returns the number constrained within the range `mn <= self <= mx`.
     #[inline]
     fn clamp(&self, mn: &$T, mx: &$T) -> $T {
-        cond!(
-            (*self > *mx) { *mx   }
-            (*self < *mn) { *mn   }
-            _             { *self }
-        )
+        match () {
+            _ if (*self > *mx) => *mx,
+            _ if (*self < *mn) => *mn,
+            _                  => *self,
+        }
     }
 }
 

src/libsyntax/ext/expand.rs

@@ -894,42 +894,6 @@ pub fn std_macros() -> @str {
         }
     )
 
-    //
-    // A scheme-style conditional that helps to improve code clarity in some instances when
-    // the `if`, `else if`, and `else` keywords obscure predicates undesirably.
-    //
-    // # Example
-    //
-    // ~~~
-    // let clamped =
-    //     if x > mx { mx }
-    //     else if x < mn { mn }
-    //     else { x };
-    // ~~~
-    //
-    // Using `cond!`, the above could be written as:
-    //
-    // ~~~
-    // let clamped = cond!(
-    //     (x > mx) { mx }
-    //     (x < mn) { mn }
-    //     _        { x  }
-    // );
-    // ~~~
-    //
-    // The optional default case is denoted by `_`.
-    //
-    macro_rules! cond (
-        ( $(($pred:expr) $body:block)+ _ $default:block ) => (
-            $(if $pred $body else)+
-            $default
-        );
-        // for if the default case was ommitted
-        ( $(($pred:expr) $body:block)+ ) => (
-            $(if $pred $body)else+
-        );
-    )
-
     // NOTE(acrichto): start removing this after the next snapshot
     macro_rules! printf (
         ($arg:expr) => (