This backport contains 1 patch from gcc main stream tree. 
The commit id of these patchs list as following in the order of time.

0001-PR93561-bounds-checking-memory-overflow-for-spill_fo.patch:
d26f37a16e3ed3d75a93ffb1da10c44c36a8a36d

diff -Nurp a/gcc/lra-assigns.c b/gcc/lra-assigns.c
--- a/gcc/lra-assigns.c	2020-04-17 16:27:46.192000000 +0800
+++ b/gcc/lra-assigns.c	2020-04-17 16:29:37.125688580 +0800
@@ -968,6 +968,8 @@ spill_for (int regno, bitmap spilled_pse
       bitmap_clear (&spill_pseudos_bitmap);
       for (j = hard_regno_nregs (hard_regno, mode) - 1; j >= 0; j--)
 	{
+	  if (hard_regno + j >= FIRST_PSEUDO_REGISTER)
+	    break;
 	  if (try_hard_reg_pseudos_check[hard_regno + j] != curr_pseudo_check)
 	    continue;
 	  lra_assert (!bitmap_empty_p (&try_hard_reg_pseudos[hard_regno + j]));