Auto merge of #75566 - alasher:master, r=oli-obk

Suppress verbose MIR comments for trivial types

Addresses #74508

This is my first contribution to the Rust project! Please let me know if anything needs revising, I'm happy to make changes.

Author: bors

src/librustc_mir/util/pretty.rs

@@ -387,20 +387,30 @@ impl Visitor<'tcx> for ExtraComments<'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
         self.super_constant(constant, location);
         let Constant { span, user_ty, literal } = constant;
-        self.push("mir::Constant");
-        self.push(&format!("+ span: {}", self.tcx.sess.source_map().span_to_string(*span)));
-        if let Some(user_ty) = user_ty {
-            self.push(&format!("+ user_ty: {:?}", user_ty));
+        match literal.ty.kind {
+            ty::Int(_) | ty::Uint(_) | ty::Bool | ty::Char => {}
+            _ => {
+                self.push("mir::Constant");
+                self.push(&format!("+ span: {}", self.tcx.sess.source_map().span_to_string(*span)));
+                if let Some(user_ty) = user_ty {
+                    self.push(&format!("+ user_ty: {:?}", user_ty));
+                }
+                self.push(&format!("+ literal: {:?}", literal));
+            }
         }
-        self.push(&format!("+ literal: {:?}", literal));
     }
 
     fn visit_const(&mut self, constant: &&'tcx ty::Const<'tcx>, _: Location) {
         self.super_const(constant);
         let ty::Const { ty, val, .. } = constant;
-        self.push("ty::Const");
-        self.push(&format!("+ ty: {:?}", ty));
-        self.push(&format!("+ val: {:?}", val));
+        match ty.kind {
+            ty::Int(_) | ty::Uint(_) | ty::Bool | ty::Char => {}
+            _ => {
+                self.push("ty::Const");
+                self.push(&format!("+ ty: {:?}", ty));
+                self.push(&format!("+ val: {:?}", val));
+            }
+        }
     }
 
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {

src/test/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir

@@ -129,23 +129,11 @@ fn address_of_reborrow() -> () {
         StorageLive(_1);                 // scope 0 at $DIR/address-of.rs:4:9: 4:10
         StorageLive(_2);                 // scope 0 at $DIR/address-of.rs:4:14: 4:21
         _2 = [const 0_i32; 10];          // scope 0 at $DIR/address-of.rs:4:14: 4:21
-                                         // ty::Const
-                                         // + ty: i32
-                                         // + val: Value(Scalar(0x00000000))
-                                         // mir::Constant
-                                         // + span: $DIR/address-of.rs:4:15: 4:16
-                                         // + literal: Const { ty: i32, val: Value(Scalar(0x00000000)) }
         _1 = &_2;                        // scope 0 at $DIR/address-of.rs:4:13: 4:21
         FakeRead(ForLet, _1);            // scope 0 at $DIR/address-of.rs:4:9: 4:10
         StorageLive(_3);                 // scope 1 at $DIR/address-of.rs:5:9: 5:14
         StorageLive(_4);                 // scope 1 at $DIR/address-of.rs:5:22: 5:29
         _4 = [const 0_i32; 10];          // scope 1 at $DIR/address-of.rs:5:22: 5:29
-                                         // ty::Const
-                                         // + ty: i32
-                                         // + val: Value(Scalar(0x00000000))
-                                         // mir::Constant
-                                         // + span: $DIR/address-of.rs:5:23: 5:24
-                                         // + literal: Const { ty: i32, val: Value(Scalar(0x00000000)) }
         _3 = &mut _4;                    // scope 1 at $DIR/address-of.rs:5:17: 5:29
         FakeRead(ForLet, _3);            // scope 1 at $DIR/address-of.rs:5:9: 5:14
         StorageLive(_5);                 // scope 2 at $DIR/address-of.rs:7:5: 7:18