From b678c238e45cd49d233edc9c885ba8a169d1ce59 Mon Sep 17 00:00:00 2001
From: nella <simontupy64@gmail.com>
Date: Fri, 10 Jul 2026 12:44:34 +0200
Subject: [PATCH 1/3] Include build datetime in scl cache hash.

---
 kernel/version.cc.in           | 1 +
 kernel/yosys.h                 | 1 +
 passes/techmap/liberty_cache.h | 3 +++
 3 files changed, 5 insertions(+)

diff --git a/kernel/version.cc.in b/kernel/version.cc.in
index b6d1139d6..399f67cec 100644
--- a/kernel/version.cc.in
+++ b/kernel/version.cc.in
@@ -1,4 +1,5 @@
 namespace Yosys {
 	const char *yosys_version_str = "@YOSYS_BUILD_INFO@";
 	const char *yosys_git_hash_str = "@YOSYS_CHECKOUT_INFO@";
+	const char *yosys_build_datetime_str = __DATE__ " " __TIME__;
 }
diff --git a/kernel/yosys.h b/kernel/yosys.h
index 9f5a16a9c..fd33a4767 100644
--- a/kernel/yosys.h
+++ b/kernel/yosys.h
@@ -82,6 +82,7 @@ extern std::set<std::string> yosys_input_files, yosys_output_files;
 // from kernel/version_*.o (cc source generated from Makefile)
 extern const char *yosys_version_str;
 extern const char *yosys_git_hash_str;
+extern const char *yosys_build_datetime_str;
 const char* yosys_maybe_version();
 
 // from passes/cmds/design.cc
diff --git a/passes/techmap/liberty_cache.h b/passes/techmap/liberty_cache.h
index 01a7bf395..0498cf8a1 100644
--- a/passes/techmap/liberty_cache.h
+++ b/passes/techmap/liberty_cache.h
@@ -49,6 +49,9 @@ inline std::string convert_liberty_files_to_merged_scl(const std::vector<std::st
 	}
 
 	hash_input += dont_use_args;
+	// Include build datetime so caches from other builds are not reused
+	hash_input += "|";
+	hash_input += yosys_build_datetime_str;
 	unsigned int hash = 0;
 
 	for (char c : hash_input)

From 68aaa349753e7c9491178a21358230c4df04073b Mon Sep 17 00:00:00 2001
From: nella <simontupy64@gmail.com>
Date: Fri, 10 Jul 2026 14:51:58 +0200
Subject: [PATCH 2/3] Reformat scl cache.

---
 passes/techmap/liberty_cache.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/passes/techmap/liberty_cache.h b/passes/techmap/liberty_cache.h
index 0498cf8a1..baab8f8be 100644
--- a/passes/techmap/liberty_cache.h
+++ b/passes/techmap/liberty_cache.h
@@ -50,7 +50,6 @@ inline std::string convert_liberty_files_to_merged_scl(const std::vector<std::st
 
 	hash_input += dont_use_args;
 	// Include build datetime so caches from other builds are not reused
-	hash_input += "|";
 	hash_input += yosys_build_datetime_str;
 	unsigned int hash = 0;
 

From eb93f5a06620e36e04a5b08c443164cd5c823969 Mon Sep 17 00:00:00 2001
From: nella <simontupy64@gmail.com>
Date: Fri, 10 Jul 2026 14:52:06 +0200
Subject: [PATCH 3/3] Add scl caching test.

---
 tests/liberty/scl_cache.ys | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 tests/liberty/scl_cache.ys

diff --git a/tests/liberty/scl_cache.ys b/tests/liberty/scl_cache.ys
new file mode 100644
index 000000000..85fbae839
--- /dev/null
+++ b/tests/liberty/scl_cache.ys
@@ -0,0 +1,7 @@
+read_verilog small.v
+synth -top small
+abc -liberty normal.lib
+
+logger -expect log "using cached merged SCL" 1
+abc -liberty normal.lib
+logger -check-expected