* optabs.h (enum optab_index): Add new OTI_signbit.
(signbit_optab): Define corresponding macro.
(enum insn_code signbit_optab[]): Remove array.
* optabs.c (init_optabs): Initialize signbit_optab using init_optab.
(expand_copysign_absneg): If back end provides signbit insn, use it
instead of bit operations on floating point argument.
* builtins.c (enum insn_code signbit_optab[]): Remove array.
(expand_builtin_signbit): Check signbit_optab->handlers[].insn_code for
availability of signbit insn.
* config/i386/i386.md (signbit<mode>2): New insn pattern to implement
signbitf, signbit and signbitl built-ins as inline x87 intrinsics when
SSE mode is not active.
(isinf<mode>2): Disable for mfpmath=sse,387.
From-SVN: r126813
