Simplify control flow for CFGs generated by eggcc. (#610)

Add a new branch simplification pass to reduce overhead introduced by RVSDGs

dag_in_context/Cargo.toml

@@ -12,7 +12,7 @@ strum_macros = "0.25"
 main_error = "0.1.2"
 thiserror = "1.0"
 egraph-serialize = "0.1.0"
-bril-rs = { git = "https://github.com/uwplse/bril", rev = "78881c45aa53231915f333d1d6dcc26cedc63b57" }
+bril-rs = { git = "https://github.com/uwplse/bril", rev = "e2be3f5" }
 indexmap = "2.0.0"
 rustc-hash = "1.1.0"
 ordered-float = "3"

dag_in_context/rust-toolchain

@@ -1 +1 @@
-1.74.0
+1.78.0

dag_in_context/src/typechecker.rs

@@ -62,8 +62,8 @@ impl Expr {
         );
         new_expr
     }
-
     /// Adds argument types to the expression.
+    #[allow(dead_code)]
     pub(crate) fn add_arg_type(self: RcExpr, input_ty: Type) -> RcExpr {
         // we need a dummy program, since there are no calls in self
         let prog = program!(function("dummy", tuplet!(), tuplet!(), empty()),);
@@ -73,6 +73,7 @@ impl Expr {
         new_expr
     }
 
+    #[allow(dead_code)]
     pub(crate) fn func_with_arg_types(self: RcExpr) -> RcExpr {
         match self.as_ref() {
             Expr::Function(name, in_ty, out_ty, body) => RcExpr::new(Expr::Function(

rust-toolchain

@@ -1 +1 @@
-1.74.0
+1.78.0

src/rvsdg/mod.rs

@@ -34,6 +34,7 @@ pub(crate) mod live_variables;
 pub(crate) mod optimize_direct_jumps;
 pub(crate) mod restructure;
 pub(crate) mod rvsdg2svg;
+pub(crate) mod simplify_branches;
 pub(crate) mod to_cfg;
 mod to_dag;
 

src/rvsdg/optimize_direct_jumps.rs

@@ -168,7 +168,16 @@ impl SimpleCfgFunction {
 impl SimpleCfgProgram {
     pub fn optimize_jumps(&self) -> Self {
         SimpleCfgProgram {
-            functions: self.functions.iter().map(|f| f.optimize_jumps()).collect(),
+            functions: self
+                .functions
+                .iter()
+                .map(|f| {
+                    // NB: We could avoid this copy by having `optimize_jumps` take `self` by value.
+                    let mut res = f.optimize_jumps();
+                    res.simplify_branches();
+                    res
+                })
+                .collect(),
         }
     }
 }