* optabs.h (enum optab_index): Add new OTI_isinf.
	(isinf_optab): Define corresponding macro.
	* optabs.c (init_optabs): Initialize isinf_optab.
	* genopinit.c (optabs): Implement isinf_optab using isinf?f2
	patterns.
	* builtins.c (mathfn_built_in): Handle BUILT_IN_ISINF{,F,L}.
	(expand_builtin_interclass_mathfn): Expand BUILT_IN_ISINF{,F,L}
	using isinf_optab.
	(expand_builtin): Expand BUILT_IN_ISINF{,F,L} using
	expand_builtin_interclass_mathfn.
	* reg_stack.c (subst_stack_regs_pat): Handle UNSPEC_FXAM.
	* config/i386/i386.md (UNSPEC_FXAM): New constant.
	(fxam<mode>2_i387): New insn pattern.
	(isinf<mode>2) New expander to implement isinf, isinff and isinfl
	built-in functions as x87 inline asm.

testsuite/ChangeLog:

	* gcc.dg/builtins-63.c: New test.

From-SVN: r121419