diff --git a/common/g45/hw-gfx-gma-plls.adb b/common/g45/hw-gfx-gma-plls.adb
index 67242f2..5db76d6 100644
--- a/common/g45/hw-gfx-gma-plls.adb
+++ b/common/g45/hw-gfx-gma-plls.adb
@@ -322,8 +322,10 @@
          -- reverse loops as hardware prefers higher values
          for M1 in reverse M1_Range range Limits.M1_Lower .. Limits.M1_Upper
          loop
+            pragma Loop_Invariant (True);
             for M2 in reverse M2_Range range Limits.M2_Lower .. Int64'Min (Limits.M2_Upper, M1)
             loop
+               pragma Loop_Invariant (True);
                for P1 in reverse P1_Range range Limits.P1_Lower .. Limits.P1_Upper
                loop
                   Verify_Parameters