Eliminate use of GetArg1() in the select_val instruction

Instead of having one i_select_val_sfI instruction that uses
the GetArg1() macro to fetch the controlling expression, use
three separate instructions for each of the register types.
That will save one word when selecting on the {x,0} register.
It should also be slightly faster since a conditional branch
is eliminated.

Although it seems that the BEAM compiler will never generate
a constant controlling expression (even with optimizations
turned off), we still make sure that they will work by
evaluating the select_val instruction at load time.

Handle the select_tuple_arity instruction in the same way.

1 files changed, 6 insertions, 2 deletions

diff --git a/erts/emulator/beam/beam_debug.c b/erts/emulator/beam/beam_debug.c
index 6c16c24d0d..46b831fa88 100644
--- a/erts/emulator/beam/beam_debug.c
+++ b/erts/emulator/beam/beam_debug.c
@@ -555,7 +555,9 @@ print_op(int to, void *to_arg, int op, int size, BeamInstr* addr)
     unpacked = ap;
     ap = addr + size;
     switch (op) {
-    case op_i_select_val_sfI:
+    case op_i_select_val_rfI:
+    case op_i_select_val_xfI:
+    case op_i_select_val_yfI:
 	{
 	    int n = ap[-1];
 
@@ -567,7 +569,9 @@ print_op(int to, void *to_arg, int op, int size, BeamInstr* addr)
 	    }
 	}
 	break;
-    case op_i_select_tuple_arity_sfI:
+    case op_i_select_tuple_arity_rfI:
+    case op_i_select_tuple_arity_xfI:
+    case op_i_select_tuple_arity_yfI:
 	{
 	    int n = ap[-1];