[gcc r17-4107] gccrs: Address review feedback for straight-line BIR drop analysis

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:b2f4914534979a5f714877f32c5ad01f40745b5e

commit r17-4107-gb2f4914534979a5f714877f32c5ad01f40745b5e
Author: Lishin <lishin1...@gmail.com>
Date:   Thu Aug 13 07:05:21 2026 +0000

    gccrs: Address review feedback for straight-line BIR drop analysis
    
    gcc/rust/ChangeLog:
    
            * checks/errors/borrowck/rust-bir-drop-analysis.cc
            (BasicBlockIdHash): New helper.
            (DropAnalysis::analyze): Use unordered_set for visited block 
tracking.
            * checks/errors/borrowck/rust-bir-drop-analysis.h: Include 
rust-bir.h
            directly and remove Function forward declaration.
            * checks/errors/borrowck/rust-bir-place.h
            (IndexVec::IndexVec): Add comment for sized constructor.
    
    Signed-off-by: Lishin <lishin1...@gmail.com>

Diff:
---
 .../checks/errors/borrowck/rust-bir-drop-analysis.cc     | 16 +++++++++++++++-
 gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.h |  3 +--
 gcc/rust/checks/errors/borrowck/rust-bir-place.h         |  1 +
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.cc 
b/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.cc
index c0de04fac2d3..006b07f22a19 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.cc
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.cc
@@ -19,14 +19,28 @@
 #include "rust-bir-drop-analysis.h"
 #include "rust-bir.h"
 
+#include <unordered_set>
+
 namespace Rust {
 namespace BIR {
 
+namespace {
+
+struct BasicBlockIdHash
+{
+  size_t operator() (BasicBlockId id) const
+  {
+    return std::hash<uint32_t> () (id.value);
+  }
+};
+
+} // namespace
+
 void
 DropAnalysis::analyze (Function &function)
 {
   std::vector<BasicBlockId> block_order;
-  std::set<BasicBlockId> visited;
+  std::unordered_set<BasicBlockId, BasicBlockIdHash> visited;
 
   BasicBlockId current = ENTRY_BASIC_BLOCK;
 
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.h 
b/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.h
index eb63f1e1eda2..c6298985a54e 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-drop-analysis.h
@@ -19,11 +19,10 @@
 #ifndef RUST_BIR_DROP_ANALYSIS_H
 #define RUST_BIR_DROP_ANALYSIS_H
 
+#include "rust-bir.h"
 namespace Rust {
 namespace BIR {
 
-struct Function;
-
 /*
   Classifies scheduled whole-local BIR Drop statements according to
   whether their place is initialized at the drop point.
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-place.h 
b/gcc/rust/checks/errors/borrowck/rust-bir-place.h
index d11ded9c9daa..46b1f5dc8965 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-place.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-place.h
@@ -209,6 +209,7 @@ template <typename I, typename T> class IndexVec
 
 public:
   IndexVec () = default;
+  // Creates `size` elements, instead of only reserving space.
   IndexVec (size_t size) : internal_vector (size) {}
 
   T &at (I pid) { return internal_vector[pid.value]; }