From a599999d1f1baf6366ccebb4e7f3f89e916c67c7 Mon Sep 17 00:00:00 2001
From: Miodrag Milanovic <mmicko@gmail.com>
Date: Mon, 18 May 2026 09:44:57 +0200
Subject: [PATCH 1/2] Fixed warnings found by gcc-16

---
 backends/jny/jny.cc     | 2 +-
 passes/cmds/abstract.cc | 1 +
 passes/cmds/sdc/sdc.cc  | 2 +-
 passes/opt/opt_merge.cc | 2 +-
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/backends/jny/jny.cc b/backends/jny/jny.cc
index 00650f5d8..2f6899f4a 100644
--- a/backends/jny/jny.cc
+++ b/backends/jny/jny.cc
@@ -275,7 +275,7 @@ struct JnyWriter
         const auto _indent = gen_indent(indent_level);
 
         bool first_port{true};
-        for (auto con : port_cell->connections()) {
+        for (auto& con : port_cell->connections()) {
             if (!first_port)
                 f << ",\n";
 
diff --git a/passes/cmds/abstract.cc b/passes/cmds/abstract.cc
index 2519daf5c..698907eb9 100644
--- a/passes/cmds/abstract.cc
+++ b/passes/cmds/abstract.cc
@@ -469,6 +469,7 @@ struct AbstractPass : public Pass {
 			switch (enable) {
 				case Enable::Always:
 					log_assert(false);
+					YS_FALLTHROUGH
 				case Enable::ActiveLow:
 				case Enable::ActiveHigh: {
 					if (enable_name.empty())
diff --git a/passes/cmds/sdc/sdc.cc b/passes/cmds/sdc/sdc.cc
index 146767b01..08cdfbf34 100644
--- a/passes/cmds/sdc/sdc.cc
+++ b/passes/cmds/sdc/sdc.cc
@@ -149,7 +149,7 @@ struct SdcObjects {
 				path += "/";
 			path += name;
 			design_cells.push_back(std::make_pair(path, cell));
-			for (auto pin : cell->connections()) {
+			for (auto& pin : cell->connections()) {
 				IdString pin_name = pin.first;
 				std::string pin_name_sdc = path + "/" + pin.first.str().substr(1);
 				design_pins.push_back(std::make_pair(pin_name_sdc, std::make_pair(cell, pin_name)));
diff --git a/passes/opt/opt_merge.cc b/passes/opt/opt_merge.cc
index a6121b268..003cfda37 100644
--- a/passes/opt/opt_merge.cc
+++ b/passes/opt/opt_merge.cc
@@ -324,7 +324,7 @@ struct OptMergeThreadWorker
 			CellEqualOp> known_cells(0, CellHashOp(), CellEqualOp(*this));
 
 		std::vector<DuplicateCell> duplicates;
-		for (const std::vector<std::vector<CellHash>> &buckets : in.bucketed_cell_hashes) {
+		for (std::vector<std::vector<CellHash>> &buckets : in.bucketed_cell_hashes) {
 			// Clear out our buckets as we go. This keeps the work of deallocation
 			// off the main thread.
 			std::vector<CellHash> bucket = std::move(buckets[index]);

From 4124649b1b781e33b90ecbf635abd209ddc722bc Mon Sep 17 00:00:00 2001
From: Miodrag Milanovic <mmicko@gmail.com>
Date: Mon, 18 May 2026 09:45:03 +0200
Subject: [PATCH 2/2] Bump CI to use gcc-16 as latest compiler

---
 .github/workflows/test-compile.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test-compile.yml b/.github/workflows/test-compile.yml
index c1dae3fbb..3093e8dfd 100644
--- a/.github/workflows/test-compile.yml
+++ b/.github/workflows/test-compile.yml
@@ -47,7 +47,7 @@ jobs:
           - 'gcc-11'
           # newest, make sure to update maximum standard step to match
           - 'clang-22'
-          - 'gcc-15'
+          - 'gcc-16'
         include:
           # macOS x86
           - os: macos-15-intel
@@ -96,7 +96,7 @@ jobs:
 
       # maximum standard, only on newest compilers
       - name: Build C++26
-        if: ${{ matrix.compiler == 'clang-22' || matrix.compiler == 'gcc-15' }}
+        if: ${{ matrix.compiler == 'clang-22' || matrix.compiler == 'gcc-16' }}
         shell: bash
         run: |
           rm -rf build