* Risc-V: return with mret from interrupt handlers, resolves #39737

compiler/riscv32/cgcpu.pas

@@ -323,7 +323,12 @@ unit cgcpu;
                 end;
           end;
 
-        list.concat(taicpu.op_reg_reg(A_JALR,NR_X0,NR_RETURN_ADDRESS_REG));
+        if po_interrupt in current_procinfo.procdef.procoptions then
+          begin
+            list.concat(Taicpu.Op_none(A_MRET));
+          end
+        else
+          list.concat(taicpu.op_reg_reg(A_JALR,NR_X0,NR_RETURN_ADDRESS_REG));
       end;
 
 

compiler/riscv64/cgcpu.pas

@@ -513,7 +513,12 @@ implementation
                 end;
           end;
 
-        list.concat(taicpu.op_reg_reg(A_JALR,NR_X0,NR_RETURN_ADDRESS_REG));
+        if po_interrupt in current_procinfo.procdef.procoptions then
+          begin
+            list.concat(Taicpu.Op_none(A_MRET));
+          end
+        else
+          list.concat(taicpu.op_reg_reg(A_JALR,NR_X0,NR_RETURN_ADDRESS_REG));
       end;