diff --git a/gcc/expr.c b/gcc/expr.c
index 798285eb52ca..a56594e78d55 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -5451,6 +5451,30 @@ expand_assignment (tree to, tree from, bool nontemporal)
 					       mode1, to_rtx, to, from,
 					       reversep))
 	    result = NULL;
+	  else if (SUBREG_P (to_rtx)
+		   && SUBREG_PROMOTED_VAR_P (to_rtx))
+	    {
+	      /* If to_rtx is a promoted subreg, we need to zero or sign
+		 extend the value afterwards.  */
+	      if (TREE_CODE (to) == MEM_REF
+		  && !REF_REVERSE_STORAGE_ORDER (to)
+		  && known_eq (bitpos, 0)
+		  && known_eq (bitsize, GET_MODE_BITSIZE (GET_MODE (to_rtx))))
+		result = store_expr (from, to_rtx, 0, nontemporal, false);
+	      else
+		{
+		  rtx to_rtx1
+		    = lowpart_subreg (subreg_unpromoted_mode (to_rtx),
+				      SUBREG_REG (to_rtx),
+				      subreg_promoted_mode (to_rtx));
+		  result = store_field (to_rtx1, bitsize, bitpos,
+					bitregion_start, bitregion_end,
+					mode1, from, get_alias_set (to),
+					nontemporal, reversep);
+		  convert_move (SUBREG_REG (to_rtx), to_rtx1,
+				SUBREG_PROMOTED_SIGN (to_rtx));
+		}
+	    }
 	  else
 	    result = store_field (to_rtx, bitsize, bitpos,
 				  bitregion_start, bitregion_end,
diff --git a/gcc/testsuite/gcc.dg/pr98190.c b/gcc/testsuite/gcc.dg/pr98190.c
new file mode 100644
index 000000000000..bfdd17d92708
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr98190.c
@@ -0,0 +1,33 @@
+/* PR middle-end/98190 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+static int __attribute__((noipa))
+foo (const char *p, const char *q, const int len)
+{
+  for (int i = 0; i < len; p++, q++, i++)
+    {
+      int equal;
+      _Bool x, y;
+      __builtin_memcpy ((char *) &x, p, sizeof x);
+      __builtin_memcpy ((char *) &y, q, sizeof y);
+      equal = (x == y);
+      if (equal <= 0)
+	return equal;
+    }
+  return 1;
+}
+
+int
+main ()
+{
+  const _Bool buf[4] = { 1, 0, 0, 0 };
+#ifdef __aarch64__
+  register long x4 asm ("x4") = 0xdeadbeefULL;
+  register long x5 asm ("x5") = 0xcafebabeULL;
+  asm volatile (""::"r" (x4), "r" (x5));
+#endif
+  if (foo ((char *) &buf[0], (char *) &buf[0], 1) != 1)
+    __builtin_abort ();
+  return 0;
+}