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-arm-aarch64-Handle-no_insn-in-TARGET_SCHED_VARIABLE_.patch
d0bc0cb66bcb0e6a5a5a31a9e900e8ccc98e34e5

diff -Nurp a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
--- a/gcc/config/aarch64/aarch64.c	2020-09-03 15:54:20.136000000 +0800
+++ b/gcc/config/aarch64/aarch64.c	2020-09-03 15:55:22.736000000 +0800
@@ -11044,6 +11044,23 @@ aarch64_sched_issue_rate (void)
   return aarch64_tune_params.issue_rate;
 }
 
+/* Implement TARGET_SCHED_VARIABLE_ISSUE.  */
+static int
+aarch64_sched_variable_issue (FILE *, int, rtx_insn *insn, int more)
+{
+  if (DEBUG_INSN_P (insn))
+    return more;
+
+  rtx_code code = GET_CODE (PATTERN (insn));
+  if (code == USE || code == CLOBBER)
+    return more;
+
+  if (get_attr_type (insn) == TYPE_NO_INSN)
+    return more;
+
+  return more - 1;
+}
+
 static int
 aarch64_sched_first_cycle_multipass_dfa_lookahead (void)
 {
@@ -19428,6 +19445,9 @@ aarch64_libgcc_floating_mode_supported_p
 #undef TARGET_SCHED_ISSUE_RATE
 #define TARGET_SCHED_ISSUE_RATE aarch64_sched_issue_rate
 
+#undef TARGET_SCHED_VARIABLE_ISSUE
+#define TARGET_SCHED_VARIABLE_ISSUE aarch64_sched_variable_issue
+
 #undef TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
 #define TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD \
   aarch64_sched_first_cycle_multipass_dfa_lookahead
diff -Nurp a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
--- a/gcc/config/arm/arm.c	2020-09-03 15:54:20.100000000 +0800
+++ b/gcc/config/arm/arm.c	2020-09-03 15:55:22.740000000 +0800
@@ -258,6 +258,7 @@ static bool arm_sched_can_speculate_insn
 static bool arm_macro_fusion_p (void);
 static bool arm_cannot_copy_insn_p (rtx_insn *);
 static int arm_issue_rate (void);
+static int arm_sched_variable_issue (FILE *, int, rtx_insn *, int);
 static int arm_first_cycle_multipass_dfa_lookahead (void);
 static int arm_first_cycle_multipass_dfa_lookahead_guard (rtx_insn *, int);
 static void arm_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED;
@@ -666,6 +667,9 @@ static const struct attribute_spec arm_a
 #undef TARGET_SCHED_ISSUE_RATE
 #define TARGET_SCHED_ISSUE_RATE arm_issue_rate
 
+#undef TARGET_SCHED_VARIABLE_ISSUE
+#define TARGET_SCHED_VARIABLE_ISSUE arm_sched_variable_issue
+
 #undef TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
 #define TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD \
   arm_first_cycle_multipass_dfa_lookahead
@@ -28316,6 +28320,23 @@ arm_issue_rate (void)
   return current_tune->issue_rate;
 }
 
+/* Implement TARGET_SCHED_VARIABLE_ISSUE.  */
+static int
+arm_sched_variable_issue (FILE *, int, rtx_insn *insn, int more)
+{
+  if (DEBUG_INSN_P (insn))
+    return more;
+
+  rtx_code code = GET_CODE (PATTERN (insn));
+  if (code == USE || code == CLOBBER)
+    return more;
+
+  if (get_attr_type (insn) == TYPE_NO_INSN)
+    return more;
+
+  return more - 1;
+}
+
 /* Return how many instructions should scheduler lookahead to choose the
    best one.  */
 static int