feat(backend): exclude MovReg use from interference during graph build\n\nWhen building the interference graph, temporarily remove the use\noperand of MovReg instructions from the live set before processing\ndefs. This prevents the source and destination of a move from\ninterfering, enabling them to be assigned the same physical register.

src/mir/RegAlloc.cpp

@@ -488,6 +488,19 @@ namespace mir
         {
           auto du = GetInstDefUse(*it, function);
 
+          // MovReg: 暂时从 live 中移除 use 操作数，使 def/use 之间不产生干涉边
+          bool is_movreg = (it->GetOpcode() == Opcode::MovReg);
+          std::vector<int> saved_uses;
+          if (is_movreg && du.defs.size() == 1 && du.uses.size() == 1)
+          {
+            int use_vreg = du.uses[0];
+            if (live.count(use_vreg) && IsGPClass(function.GetVRegClass(use_vreg)))
+            {
+              live.erase(use_vreg);
+              saved_uses.push_back(use_vreg);
+            }
+          }
+
           for (int d : du.defs)
           {
             if (!IsGPClass(function.GetVRegClass(d)))
@@ -499,6 +512,9 @@ namespace mir
             }
             live.erase(d);
           }
+          // 恢复 MovReg 的 use
+          for (int u : saved_uses)
+            live.insert(u);
           for (int u : du.uses)
           {
             if (IsGPClass(function.GetVRegClass(u)))
@@ -560,6 +576,19 @@ namespace mir
         {
           auto du = GetInstDefUse(*it, function);
 
+          // MovReg: 暂时从 live 中移除 use 操作数，使 def/use 之间不产生干涉边
+          bool is_movreg = (it->GetOpcode() == Opcode::MovReg);
+          std::vector<int> saved_uses;
+          if (is_movreg && du.defs.size() == 1 && du.uses.size() == 1)
+          {
+            int use_vreg = du.uses[0];
+            if (live.count(use_vreg) && function.GetVRegClass(use_vreg) == VRegClass::Float)
+            {
+              live.erase(use_vreg);
+              saved_uses.push_back(use_vreg);
+            }
+          }
+
           for (int d : du.defs)
           {
             if (function.GetVRegClass(d) != VRegClass::Float)
@@ -571,6 +600,9 @@ namespace mir
             }
             live.erase(d);
           }
+          // 恢复 MovReg 的 use
+          for (int u : saved_uses)
+            live.insert(u);
           for (int u : du.uses)
           {
             if (function.GetVRegClass(u) == VRegClass::Float)