Auto merge of #129261 - tgross35:rollup-xjbvqx7, r=tgross35

Rollup of 7 pull requests

Successful merges:

 - #127679 (Stabilize `raw_ref_op` (RFC 2582))
 - #128084 (Suggest adding Result return type for associated method in E0277.)
 - #128628 (When deduplicating unreachable blocks, erase the source information.)
 - #128902 (doc: std::env::var: Returns None for names with '=' or NUL byte)
 - #129048 (Update `crosstool-ng` for loongarch64)
 - #129116 (Include a copy of `compiler-rt` source in the `download-ci-llvm` tarball)
 - #129208 (Fix order of normalization and recursion in const folding.)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 5bbe3bb747f..4fe8cf6213f 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -31,6 +31,7 @@ use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
+use rustc_span::DUMMY_SP;
 use smallvec::SmallVec;
 
 pub enum SimplifyCfg {
@@ -318,6 +319,7 @@ pub(crate) fn remove_dead_blocks(body: &mut Body<'_>) {
     let mut orig_index = 0;
     let mut used_index = 0;
     let mut kept_unreachable = None;
+    let mut deduplicated_unreachable = false;
     basic_blocks.raw.retain(|bbdata| {
         let orig_bb = BasicBlock::new(orig_index);
         if !reachable.contains(orig_bb) {
@@ -330,6 +332,7 @@ pub(crate) fn remove_dead_blocks(body: &mut Body<'_>) {
             let kept_unreachable = *kept_unreachable.get_or_insert(used_bb);
             if kept_unreachable != used_bb {
                 replacements[orig_index] = kept_unreachable;
+                deduplicated_unreachable = true;
                 orig_index += 1;
                 return false;
             }
@@ -341,6 +344,14 @@ pub(crate) fn remove_dead_blocks(body: &mut Body<'_>) {
         true
     });
 
+    // If we deduplicated unreachable blocks we erase their source_info as we
+    // can no longer attribute their code to a particular location in the
+    // source.
+    if deduplicated_unreachable {
+        basic_blocks[kept_unreachable.unwrap()].terminator_mut().source_info =
+            SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE };
+    }
+
     for block in basic_blocks {
         for target in block.terminator_mut().successors_mut() {
             *target = replacements[target.index()];