Rollup merge of rust-lang#110714 - cjgillot:reveal-consts, r=oli-obk

Normalize types and consts in MIR opts.

Some passes were using a non-RevealAll param_env, which is needlessly restrictive in mir-opts.

As a drive-by, we normalize all constants, since just normalizing their types is not enough.

Author: matthiaskrgr

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -323,7 +323,7 @@ impl<'tcx> std::fmt::Debug for ScalarTy<'tcx> {
 
 impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
     pub fn new(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, map: Map) -> Self {
-        let param_env = tcx.param_env(body.source.def_id());
+        let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         Self {
             map,
             tcx,

compiler/rustc_mir_transform/src/large_enums.rs

@@ -120,7 +120,7 @@ impl EnumSizeOpt {
     fn optim<'tcx>(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let mut alloc_cache = FxHashMap::default();
         let body_did = body.source.def_id();
-        let param_env = tcx.param_env(body_did);
+        let param_env = tcx.param_env_reveal_all_normalized(body_did);
 
         let blocks = body.basic_blocks.as_mut();
         let local_decls = &mut body.local_decls;

compiler/rustc_mir_transform/src/match_branches.rs

@@ -46,7 +46,7 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let def_id = body.source.def_id();
-        let param_env = tcx.param_env(def_id);
+        let param_env = tcx.param_env_reveal_all_normalized(def_id);
 
         let bbs = body.basic_blocks.as_mut();
         let mut should_cleanup = false;

compiler/rustc_mir_transform/src/reveal_all.rs

@@ -34,11 +34,23 @@ impl<'tcx> MutVisitor<'tcx> for RevealAllVisitor<'tcx> {
         self.tcx
     }
 
+    #[inline]
+    fn visit_constant(&mut self, constant: &mut Constant<'tcx>, _: Location) {
+        // We have to use `try_normalize_erasing_regions` here, since it's
+        // possible that we visit impossible-to-satisfy where clauses here,
+        // see #91745
+        if let Ok(c) = self.tcx.try_normalize_erasing_regions(self.param_env, constant.literal) {
+            constant.literal = c;
+        }
+    }
+
     #[inline]
     fn visit_ty(&mut self, ty: &mut Ty<'tcx>, _: TyContext) {
         // We have to use `try_normalize_erasing_regions` here, since it's
         // possible that we visit impossible-to-satisfy where clauses here,
         // see #91745
-        *ty = self.tcx.try_normalize_erasing_regions(self.param_env, *ty).unwrap_or(*ty);
+        if let Ok(t) = self.tcx.try_normalize_erasing_regions(self.param_env, *ty) {
+            *ty = t;
+        }
     }
 }

compiler/rustc_mir_transform/src/shim.rs

@@ -355,7 +355,7 @@ fn build_thread_local_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'t
 fn build_clone_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, self_ty: Ty<'tcx>) -> Body<'tcx> {
     debug!("build_clone_shim(def_id={:?})", def_id);
 
-    let param_env = tcx.param_env(def_id);
+    let param_env = tcx.param_env_reveal_all_normalized(def_id);
 
     let mut builder = CloneShimBuilder::new(tcx, def_id, self_ty);
     let is_copy = self_ty.is_copy_modulo_regions(tcx, param_env);
@@ -836,7 +836,7 @@ fn build_call_shim<'tcx>(
 pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
     debug_assert!(tcx.is_constructor(ctor_id));
 
-    let param_env = tcx.param_env(ctor_id);
+    let param_env = tcx.param_env_reveal_all_normalized(ctor_id);
 
     // Normalize the sig.
     let sig = tcx

compiler/rustc_mir_transform/src/simplify_branches.rs

@@ -16,7 +16,7 @@ impl<'tcx> MirPass<'tcx> for SimplifyConstCondition {
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let param_env = tcx.param_env(body.source.def_id());
+        let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         for block in body.basic_blocks_mut() {
             let terminator = block.terminator_mut();
             terminator.kind = match terminator.kind {

compiler/rustc_mir_transform/src/simplify_comparison_integral.rs

@@ -37,7 +37,7 @@ impl<'tcx> MirPass<'tcx> for SimplifyComparisonIntegral {
         let opts = helper.find_optimizations();
         let mut storage_deads_to_insert = vec![];
         let mut storage_deads_to_remove: Vec<(usize, BasicBlock)> = vec![];
-        let param_env = tcx.param_env(body.source.def_id());
+        let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         for opt in opts {
             trace!("SUCCESS: Applying {:?}", opt);
             // replace terminator with a switchInt that switches on the integer directly

compiler/rustc_mir_transform/src/uninhabited_enum_branching.rs

@@ -109,7 +109,9 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching {
                 continue;
             };
 
-            let layout = tcx.layout_of(tcx.param_env(body.source.def_id()).and(discriminant_ty));
+            let layout = tcx.layout_of(
+                tcx.param_env_reveal_all_normalized(body.source.def_id()).and(discriminant_ty),
+            );
 
             let allowed_variants = if let Ok(layout) = layout {
                 variant_discriminants(&layout, discriminant_ty, tcx)