From e4ad23a1a594a9da6b96655d4256352d5f6d277d Mon Sep 17 00:00:00 2001
From: Lixuanwang <xlwmail@nudt.edu.cn>
Date: Sun, 3 Aug 2025 18:37:08 +0800
Subject: [PATCH] =?UTF-8?q?[backend]=E4=BF=AE=E5=A4=8D=E4=BA=86=E5=AF=84?=
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---
 script/runit-single.sh                  |  2 +-
 src/backend/RISCv64/RISCv64RegAlloc.cpp | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/script/runit-single.sh b/script/runit-single.sh
index c6dacee..3cc47aa 100644
--- a/script/runit-single.sh
+++ b/script/runit-single.sh
@@ -184,7 +184,7 @@ for sy_file in "${SY_FILES[@]}"; do
     # 步骤 1: sysyc 编译
     echo "  使用 sysyc 编译 (超时 ${SYSYC_TIMEOUT}s)..."
     timeout -s KILL ${SYSYC_TIMEOUT} "${SYSYC}" -S "${sy_file}" ${OPTIMIZE_FLAG} -o "${assembly_file}"
-    # timeout -s KILL ${SYSYC_TIMEOUT} "${SYSYC}" -s ir "${sy_file}" ${OPTIMIZE_FLAG} > "${ir_file}"
+    timeout -s KILL ${SYSYC_TIMEOUT} "${SYSYC}" -s ir "${sy_file}" ${OPTIMIZE_FLAG} > "${ir_file}"
     # timeout -s KILL ${SYSYC_TIMEOUT} "${SYSYC}" -s asmd "${sy_file}" > "${assembly_debug_file}" 2>&1
     SYSYC_STATUS=$?
     if [ $SYSYC_STATUS -eq 124 ]; then
diff --git a/src/backend/RISCv64/RISCv64RegAlloc.cpp b/src/backend/RISCv64/RISCv64RegAlloc.cpp
index a1cd77c..87f276f 100644
--- a/src/backend/RISCv64/RISCv64RegAlloc.cpp
+++ b/src/backend/RISCv64/RISCv64RegAlloc.cpp
@@ -461,6 +461,17 @@ void RISCv64RegAlloc::coalesce() {
     unsigned y = getAlias(*use.begin());
     unsigned u, v;
     if (precolored.count(y)) { u = y; v = x; } else { u = x; v = y; }
+    
+    // 防御性检查，处理物理寄存器之间的传送指令
+    if (precolored.count(u) && precolored.count(v)) {
+        // 如果 u 和 v 都是物理寄存器，我们不能合并它们。
+        // 这通常是一条寄存器拷贝指令，例如 `mv a2, a1`。
+        // 把它加入 constrainedMoves 列表，然后直接返回，不再处理。
+        constrainedMoves.insert(move);
+        // addWorklist(u) 和 addWorklist(v) 在这里也不需要调用，
+        // 因为它们只对虚拟寄存器有意义。
+        return;
+    }
 
     if (DEEPERDEBUG) std::cerr << "[Coalesce] Processing move between " << regIdToString(x) 
                            << " and " << regIdToString(y) << " (aliases " << regIdToString(u)