[committed] avoid double evaluation of PIC_OFFSET_TABLE_REGNUM

[Aldy Hernandez]

This patch was approved for stage1 a few months back, and I've neglected 
to commit it.  There are no changes from the posted patch.

https://gcc.gnu.org/ml/gcc-patches/2016-03/msg01373.html
Committed to trunk.
commit 5321d430b8d2cf33ff2b5fd9d6cc3f8d1304b0a2
Author: Aldy Hernandez <al...@redhat.com>
Date:   Thu Mar 24 22:44:59 2016 -0500

        * builtins.c (expand_builtin_nonlocal_goto): Avoid evaluating
        PIC_OFFSET_TABLE_REGNUM twice.

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 997c0e8..cc711a0 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -1140,8 +1140,8 @@ expand_builtin_nonlocal_goto (tree exp)
         to targets with a nonlocal_goto pattern; they are free
         to implement it in their own way.  Note also that this is
         a no-op if the GP register is a global invariant.)  */
-      if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
-         && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
+      unsigned regnum = PIC_OFFSET_TABLE_REGNUM;
+      if (regnum != INVALID_REGNUM && fixed_regs[regnum])
        emit_use (pic_offset_table_rtx);
 
       emit_indirect_jump (r_label);