Auto merge of rust-lang#131650 - saethlin:post-mono-mir-opts, r=<try>

Add post-mono MIR passes to make mono-reachable analysis more accurate

r? ghost

Author: bors

compiler/rustc_codegen_cranelift/src/base.rs

@@ -41,7 +41,7 @@ pub(crate) fn codegen_fn<'tcx>(
     let symbol_name = tcx.symbol_name(instance).name.to_string();
     let _timer = tcx.prof.generic_activity_with_arg("codegen fn", &*symbol_name);
 
-    let mir = tcx.instance_mir(instance.def);
+    let mir = tcx.build_codegen_mir(instance);
     let _mir_guard = crate::PrintOnPanic(|| {
         let mut buf = Vec::new();
         with_no_trimmed_paths!({

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -167,7 +167,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     let llfn = cx.get_fn(instance);
 
-    let mir = cx.tcx().instance_mir(instance.def);
+    let mir = cx.tcx().build_codegen_mir(instance);
 
     let fn_abi = cx.fn_abi_of_instance(instance, ty::List::empty());
     debug!("fn_abi: {:?}", fn_abi);

compiler/rustc_middle/src/mir/mod.rs

@@ -159,6 +159,7 @@ impl RuntimePhase {
             "initial" => Self::Initial,
             "post_cleanup" | "post-cleanup" | "postcleanup" => Self::PostCleanup,
             "optimized" => Self::Optimized,
+            "codegen" => Self::Codegen,
             _ => bug!("Unknown runtime phase: '{}'", phase),
         }
     }

compiler/rustc_middle/src/mir/mono.rs

@@ -73,7 +73,7 @@ impl<'tcx> MonoItem<'tcx> {
                     InstanceKind::Item(..)
                     | InstanceKind::DropGlue(..)
                     | InstanceKind::AsyncDropGlueCtorShim(..) => {
-                        let mir = tcx.instance_mir(instance.def);
+                        let mir = tcx.build_codegen_mir(instance);
                         mir.basic_blocks.iter().map(|bb| bb.statements.len() + 1).sum()
                     }
                     // Other compiler-generated shims size estimate: 1