2007-07-09  Wolfgang Gellerich  <gellerich@de.ibm.com>

	* optabs.h: Added declaration for signbit_optab.  
	* optabs.c: (init_optabs): Added initialization for signbit_optab.
	* genoptinit.c (optabs): Added entry for signbit insns.  
	* builtins.c (expand_builtin_signbit): Added code to use a signbit insn,
	if available.  
	* config/s390/s390.h (S390_TDC_SIGNBIT_SET): New constant.  
	* config/s390/s390.md (signbit<mode>2): New expander.

From-SVN: r126495