[MIR] Implement move up propagation without post dominators

src/librustc/mir/repr.rs

@@ -180,6 +180,27 @@ impl<'tcx> Mir<'tcx> {
         Some(Local::new(idx))
     }
 
+    pub fn from_local_index_to_temp(&self, local: Local) -> Option<Temp> {
+        let num_args_and_vars = self.arg_decls.len() + self.var_decls.len();
+        if local.index() < num_args_and_vars {
+            None
+        } else if local.index() >= num_args_and_vars + self.temp_decls.len() {
+            None
+        } else {
+            Some(Temp::new(local.index() - num_args_and_vars))
+        }
+    }
+    pub fn from_local_index_to_var(&self, local: Local) -> Option<Var> {
+        let num_args = self.arg_decls.len();
+        if local.index() < num_args {
+            None
+        } else if local.index() >= num_args + self.var_decls.len() {
+            None
+        } else {
+            Some(Var::new(local.index() - num_args))
+        }
+    }
+
     /// Counts the number of locals, such that that local_index
     /// will always return an index smaller than this count.
     pub fn count_locals(&self) -> usize {
@@ -710,7 +731,7 @@ newtype_index!(Local, "local");
 
 /// A path to a value; something that can be evaluated without
 /// changing or disturbing program state.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Eq, Hash)]
 pub enum Lvalue<'tcx> {
     /// local variable declared by the user
     Var(Var),
@@ -868,7 +889,7 @@ pub struct VisibilityScopeData {
 /// These are values that can appear inside an rvalue (or an index
 /// lvalue). They are intentionally limited to prevent rvalues from
 /// being nested in one another.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Eq, Hash)]
 pub enum Operand<'tcx> {
     Consume(Lvalue<'tcx>),
     Constant(Constant<'tcx>),

src/librustc_driver/driver.rs

@@ -998,6 +998,7 @@ pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         passes.push_pass(box mir::transform::deaggregator::Deaggregator);
 
         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
+        passes.push_pass(box mir::transform::move_up_propagation::MoveUpPropagation);
         passes.push_pass(box mir::transform::dump_mir::Marker("PreTrans"));
 
         passes.run_passes(tcx, &mut mir_map);

src/librustc_mir/transform/dump_mir.rs

@@ -34,6 +34,15 @@ pub struct Disambiguator<'a> {
     is_after: bool
 }
 
+impl<'a> Disambiguator<'a> {
+    pub fn new(pass: &'a Pass, is_after: bool) -> Self {
+        Disambiguator {
+            pass: pass,
+            is_after : is_after
+        }
+    }
+}
+
 impl<'a> fmt::Display for Disambiguator<'a> {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         let title = if self.is_after { "after" } else { "before" };

src/librustc_mir/transform/mod.rs

@@ -18,3 +18,5 @@ pub mod promote_consts;
 pub mod qualify_consts;
 pub mod dump_mir;
 pub mod deaggregator;
+pub mod move_up_propagation;
+