Enable egraph-based optimization by default.

cranelift/codegen/meta/src/shared/settings.rs

@@ -58,10 +58,12 @@ pub(crate) fn define() -> SettingGroup {
         "Enable egraph-based optimization.",
         r#"
             This enables an optimization phase that converts CLIF to an egraph (equivalence graph)
-            representation, performs various rewrites, and then converts it back. This can result in
-            better optimization, but is currently considered experimental.
+            representation, performs various rewrites, and then converts it back. This should result in
+            better optimization, but the traditional optimization pass structure is also still
+            available by setting this to `false`. The `false` setting will eventually be
+            deprecated and removed.
         "#,
-        false,
+        true,
     );
 
     settings.add_bool(

cranelift/codegen/src/context.rs

@@ -185,18 +185,20 @@ impl Context {
         self.compute_domtree();
         self.eliminate_unreachable_code(isa)?;
 
-        if isa.flags().use_egraphs() || opt_level != OptLevel::None {
+        if opt_level != OptLevel::None {
             self.dce(isa)?;
         }
 
         self.remove_constant_phis(isa)?;
 
-        if isa.flags().use_egraphs() {
-            self.egraph_pass()?;
-        } else if opt_level != OptLevel::None && isa.flags().enable_alias_analysis() {
-            for _ in 0..2 {
-                self.replace_redundant_loads()?;
-                self.simple_gvn(isa)?;
+        if opt_level != OptLevel::None {
+            if isa.flags().use_egraphs() {
+                self.egraph_pass()?;
+            } else if isa.flags().enable_alias_analysis() {
+                for _ in 0..2 {
+                    self.replace_redundant_loads()?;
+                    self.simple_gvn(isa)?;
+                }
             }
         }
 

cranelift/codegen/src/machinst/isle.rs

@@ -16,7 +16,7 @@ pub use crate::machinst::{
     ABIArg, ABIArgSlot, InputSourceInst, Lower, LowerBackend, RealReg, Reg, RelocDistance, Sig,
     VCodeInst, Writable,
 };
-pub use crate::settings::TlsModel;
+pub use crate::settings::{OptLevel, TlsModel};
 
 pub type Unit = ();
 pub type ValueSlice = (ValueList, usize);
@@ -131,7 +131,9 @@ macro_rules! isle_lower_prelude_methods {
             // use. This lowers register pressure. (Only do this if we are
             // not using egraph-based compilation; the egraph framework
             // more efficiently rematerializes constants where needed.)
-            if !self.backend.flags().use_egraphs() {
+            if !(self.backend.flags().use_egraphs()
+                && self.backend.flags().opt_level() != OptLevel::None)
+            {
                 let inputs = self.lower_ctx.get_value_as_source_or_const(val);
                 if inputs.constant.is_some() {
                     let insn = match inputs.inst {

cranelift/codegen/src/settings.rs

@@ -528,7 +528,7 @@ probestack_strategy = "outline"
 regalloc_checker = false
 regalloc_verbose_logs = false
 enable_alias_analysis = true
-use_egraphs = false
+use_egraphs = true
 enable_verifier = true
 is_pic = false
 use_colocated_libcalls = false

cranelift/filetests/filetests/egraph/algebraic.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/alias_analysis.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/basic-gvn.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/cprop.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/i128-opts.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=speed_and_size
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/isplit.clif

@@ -1,6 +1,6 @@
 test interpret
 test run
-set opt_level=speed_and_size
+set opt_level=speed
 set use_egraphs=true
 set enable_llvm_abi_extensions=true
 target x86_64

cranelift/filetests/filetests/egraph/issue-5405.clif

@@ -1,6 +1,6 @@
 test interpret
 test run
-set opt_level=speed_and_size
+set opt_level=speed
 set use_egraphs=true
 target aarch64
 

cranelift/filetests/filetests/egraph/issue-5437.clif

@@ -1,4 +1,5 @@
 test compile
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 target aarch64

cranelift/filetests/filetests/egraph/licm.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/misc.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/multivalue.clif

@@ -1,4 +1,5 @@
 test compile precise-output
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/not_a_load.clif

@@ -1,4 +1,5 @@
 test compile precise-output
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/egraph/remat.clif

@@ -1,5 +1,5 @@
 test optimize
-set opt_level=none
+set opt_level=speed
 set use_egraphs=true
 target x86_64
 

cranelift/filetests/filetests/wasm/duplicate-loads-dynamic-memory.wat

@@ -4,7 +4,8 @@
 ;;!
 ;;! settings = [
 ;;!   "enable_heap_access_spectre_mitigation=true",
-;;!   "opt_level=speed_and_size"
+;;!   "opt_level=speed_and_size",
+;;!   "use_egraphs=false"
 ;;! ]
 ;;!
 ;;! [globals.vmctx]
@@ -112,4 +113,4 @@
 ;;
 ;;                                 block1:
 ;; @006e                               return v14, v14
-;; }
+;; }

cranelift/filetests/filetests/wasm/duplicate-loads-static-memory.wat

@@ -4,7 +4,8 @@
 ;;!
 ;;! settings = [
 ;;!   "enable_heap_access_spectre_mitigation=true",
-;;!   "opt_level=speed_and_size"
+;;!   "opt_level=speed_and_size",
+;;!   "use_egraphs=false"
 ;;! ]
 ;;!
 ;;! [globals.vmctx]

crates/wasmtime/src/config.rs

@@ -832,14 +832,13 @@ impl Config {
     /// Configures the Cranelift code generator to use its
     /// "egraph"-based mid-end optimizer.
     ///
-    /// This optimizer is intended to replace the compiler's more
-    /// traditional pipeline of optimization passes with a unified
-    /// code-rewriting system. It is not yet on by default, but it is
-    /// intended to become the default in a future version. It may
-    /// result in faster code, at the cost of slightly more
-    /// compilation-time work.
-    ///
-    /// The default value for this is `false`.
+    /// This optimizer has replaced the compiler's more traditional
+    /// pipeline of optimization passes with a unified code-rewriting
+    /// system. It is on by default, but the traditional optimization
+    /// pass structure is still available for now (it is deprecrated and
+    /// will be removed in a future version).
+    ///
+    /// The default value for this is `true`.
     #[cfg(compiler)]
     #[cfg_attr(nightlydoc, doc(cfg(feature = "cranelift")))] // see build.rs
     pub fn cranelift_use_egraphs(&mut self, enable: bool) -> &mut Self {