combine: Use single_set for is_just_move

Since we now only call is_just_move on the original instructions, we
always have an rtx_insn* (not just a pattern), so we can use single_set
on it.  This makes no detectable difference at all on all thirty Linux
targets I test, but it does help cris, and it is simpler, cleaner code
anyway.

2020-07-16  Hans-Peter Nilsson  <hp@axis.com>
	    Segher Boessenkool  <segher@kernel.crashing.org>

	PR target/93372
	* combine.c (is_just_move): Take an rtx_insn* as argument.  Use
	single_set on it.

diff --git a/gcc/combine.c b/gcc/combine.c
index b044f29fd36b37b4da74dea971ce521403cc870c..4fee114b3cc141de18f05ec9b243e36f0855de33 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -2624,15 +2624,16 @@ can_split_parallel_of_n_reg_sets (rtx_insn *insn, int n)
   return true;
 }
 
-/* Return whether X is just a single set, with the source
+/* Return whether X is just a single_set, with the source
    a general_operand.  */
 static bool
-is_just_move (rtx x)
+is_just_move (rtx_insn *x)
 {
-  if (INSN_P (x))
-    x = PATTERN (x);
+  rtx set = single_set (x);
+  if (!set)
+    return false;
 
-  return (GET_CODE (x) == SET && general_operand (SET_SRC (x), VOIDmode));
+  return general_operand (SET_SRC (set), VOIDmode);
 }
 
 /* Callback function to count autoincs.  */