diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 64801b6fcce..698d8d04a1e 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -3459,12 +3459,17 @@ process_address_1 (int nop, bool check_only_p,
       constraint
 	= skip_contraint_modifiers (curr_static_id->operand[dup].constraint);
     }
-  if (*skip_contraint_modifiers (constraint
-				 + CONSTRAINT_LEN (constraint[0],
-						   constraint)) != '\0')
+  cn = lookup_constraint (*constraint == '\0' ? "X" : constraint);
+  /* If we have several alternatives or/and several constraints in an
+     alternative and we can not say at this stage what constraint will be used,
+     use unknown constraint.  The exception is an address constraint.  If
+     operand has one address constraint, probably all others constraints are
+     address ones.  */
+  if (get_constraint_type (cn) != CT_ADDRESS
+      && *skip_contraint_modifiers (constraint
+				    + CONSTRAINT_LEN (constraint[0],
+						      constraint)) != '\0')
     cn = CONSTRAINT__UNKNOWN;
-  else
-    cn = lookup_constraint (*constraint == '\0' ? "X" : constraint);
   if (insn_extra_address_constraint (cn)
       /* When we find an asm operand with an address constraint that
 	 doesn't satisfy address_operand to begin with, we clear
diff --git a/gcc/testsuite/gcc.target/s390/pr99663.c b/gcc/testsuite/gcc.target/s390/pr99663.c
new file mode 100644
index 00000000000..f4f0f94a63a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/pr99663.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-mtune=z15 -march=z13 -mzarch -O2 -fno-stack-protector -fPIC" } */
+
+typedef struct {
+  int exponent;
+  unsigned short lsu[];
+} decNumber;
+decNumber decDivideOp_lhs;
+short decDivideOp_varbuff;
+void decDivideOp(decNumber *rhs) {
+  short *msu1;
+  int exponent;
+  unsigned short *source;
+  for (; source >= decDivideOp_lhs.lsu; source--, msu1--)
+    *msu1 = *source;
+  for (;;)
+    if (exponent)
+      if (decDivideOp_varbuff)
+        exponent = rhs->exponent;
+}