[RS6000] Count rldimi constant insns

[Alan Modra via Gcc-patches]

rldimi is generated by rs6000_emit_set_long_const when the high and
low 32 bits of a 64-bit constant are equal.

        * config/rs6000/rs6000.c (num_insns_constant_gpr): Count rldimi
        constants correctly.

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 20a4ba382bc..6fc86f8185a 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -5731,7 +5731,7 @@ direct_return (void)
 
 /* Helper for num_insns_constant.  Calculate number of instructions to
    load VALUE to a single gpr using combinations of addi, addis, ori,
-   oris and sldi instructions.  */
+   oris, sldi and rldimi instructions.  */
 
 static int
 num_insns_constant_gpr (HOST_WIDE_INT value)
@@ -5759,7 +5759,7 @@ num_insns_constant_gpr (HOST_WIDE_INT value)
 
       high >>= 1;
 
-      if (low == 0)
+      if (low == 0 || low == high)
        return num_insns_constant_gpr (high) + 1;
       else if (high == 0)
        return num_insns_constant_gpr (low) + 1;