Rollup merge of #82736 - spastorino:mir-opt-level-perf-changes, r=oli-obk

Bump optimization from mir_opt_level 2 to 3 and 3 to 4 and make "release" be level 2 by default

r? `@oli-obk`

Author: GuillaumeGomez

compiler/rustc_interface/src/tests.rs

@@ -566,7 +566,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(link_only, true);
     tracked!(merge_functions, Some(MergeFunctions::Disabled));
     tracked!(mir_emit_retag, true);
-    tracked!(mir_opt_level, 3);
+    tracked!(mir_opt_level, Some(4));
     tracked!(mutable_noalias, true);
     tracked!(new_llvm_pass_manager, true);
     tracked!(no_codegen, true);

compiler/rustc_mir/src/transform/const_goto.rs

@@ -28,7 +28,7 @@ pub struct ConstGoto;
 
 impl<'tcx> MirPass<'tcx> for ConstGoto {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
+        if tcx.sess.mir_opt_level() < 4 {
             return;
         }
         trace!("Running ConstGoto on {:?}", body.source);

compiler/rustc_mir/src/transform/const_prop.rs

@@ -725,7 +725,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 3 {
+        if self.tcx.sess.mir_opt_level() >= 4 {
             self.eval_rvalue_with_identities(rvalue, place)
         } else {
             self.use_ecx(|this| this.ecx.eval_rvalue_into_place(rvalue, place))
@@ -903,7 +903,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
 
     /// Returns `true` if and only if this `op` should be const-propagated into.
     fn should_const_prop(&mut self, op: &OpTy<'tcx>) -> bool {
-        let mir_opt_level = self.tcx.sess.opts.debugging_opts.mir_opt_level;
+        let mir_opt_level = self.tcx.sess.mir_opt_level();
 
         if mir_opt_level == 0 {
             return false;
@@ -1071,9 +1071,9 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
     fn visit_operand(&mut self, operand: &mut Operand<'tcx>, location: Location) {
         self.super_operand(operand, location);
 
-        // Only const prop copies and moves on `mir_opt_level=2` as doing so
+        // Only const prop copies and moves on `mir_opt_level=3` as doing so
         // currently slightly increases compile time in some cases.
-        if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 2 {
+        if self.tcx.sess.mir_opt_level() >= 3 {
             self.propagate_operand(operand)
         }
     }
@@ -1253,7 +1253,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
             TerminatorKind::SwitchInt { ref mut discr, .. } => {
                 // FIXME: This is currently redundant with `visit_operand`, but sadly
                 // always visiting operands currently causes a perf regression in LLVM codegen, so
-                // `visit_operand` currently only runs for propagates places for `mir_opt_level=3`.
+                // `visit_operand` currently only runs for propagates places for `mir_opt_level=4`.
                 self.propagate_operand(discr)
             }
             // None of these have Operands to const-propagate.
@@ -1272,7 +1272,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
             // Every argument in our function calls have already been propagated in `visit_operand`.
             //
             // NOTE: because LLVM codegen gives slight performance regressions with it, so this is
-            // gated on `mir_opt_level=2`.
+            // gated on `mir_opt_level=3`.
             TerminatorKind::Call { .. } => {}
         }
 

compiler/rustc_mir/src/transform/deduplicate_blocks.rs

@@ -16,7 +16,7 @@ pub struct DeduplicateBlocks;
 
 impl<'tcx> MirPass<'tcx> for DeduplicateBlocks {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
+        if tcx.sess.mir_opt_level() < 4 {
             return;
         }
         debug!("Running DeduplicateBlocks on `{:?}`", body.source);

compiler/rustc_mir/src/transform/dest_prop.rs

@@ -127,9 +127,9 @@ pub struct DestinationPropagation;
 
 impl<'tcx> MirPass<'tcx> for DestinationPropagation {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        // Only run at mir-opt-level=2 or higher for now (we don't fix up debuginfo and remove
+        // Only run at mir-opt-level=3 or higher for now (we don't fix up debuginfo and remove
         // storage statements at the moment).
-        if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
+        if tcx.sess.mir_opt_level() < 3 {
             return;
         }
 

compiler/rustc_mir/src/transform/early_otherwise_branch.rs

@@ -26,7 +26,7 @@ pub struct EarlyOtherwiseBranch;
 
 impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
+        if tcx.sess.mir_opt_level() < 3 {
             return;
         }
         trace!("running EarlyOtherwiseBranch on {:?}", body.source);

compiler/rustc_mir/src/transform/inline.rs

@@ -52,7 +52,7 @@ crate fn is_enabled(tcx: TyCtxt<'_>) -> bool {
         return enabled;
     }
 
-    tcx.sess.opts.debugging_opts.mir_opt_level >= 2
+    tcx.sess.mir_opt_level() >= 3
 }
 
 impl<'tcx> MirPass<'tcx> for Inline {

compiler/rustc_mir/src/transform/match_branches.rs

@@ -40,7 +40,7 @@ pub struct MatchBranchSimplification;
 
 impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
+        if tcx.sess.mir_opt_level() < 3 {
             return;
         }
 

compiler/rustc_mir/src/transform/mod.rs

@@ -475,7 +475,7 @@ fn run_post_borrowck_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tc
 }
 
 fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-    let mir_opt_level = tcx.sess.opts.debugging_opts.mir_opt_level;
+    let mir_opt_level = tcx.sess.mir_opt_level();
 
     // Lowering generator control-flow and variables has to happen before we do anything else
     // to them. We run some optimizations before that, because they may be harder to do on the state

compiler/rustc_mir/src/transform/multiple_return_terminators.rs

@@ -10,7 +10,7 @@ pub struct MultipleReturnTerminators;
 
 impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
+        if tcx.sess.mir_opt_level() < 4 {
             return;
         }