i386.md (expsf2, [...]): New patterns to implement exp, expf and expl built-ins as...

i386.md (expsf2, [...]): New patterns to implement exp, expf and expl built-ins as inline x87 intrinsics.

	* config/i386/i386.md (expsf2, expdf2, expxf2): New patterns to
	implement exp, expf and expl built-ins as inline x87 intrinsics.
	(UNSPEC_FSCALE, UNSPEC_FRNDINT, UNSPEC_F2XM1): New unspecs to
	represent x87's fscale, frndint and f2xm1 insns respectively.
	(*fscale_sfxf3, *fscale_dfxf3, *fscale_xf3): New insn patterns
	to encode x87's "fscale" instruction followed by a pop.
	(*frndintxf2): New insn pattern for "frndint".
	(*f2xm1xf2): New insn pattern for "f2xm1".

	* reg-stack.c (subst_stack_regs_pat): Handle UNSPEC_FRNDINT and
	UNSPEC_F2XM1 like UNSPEC_{SIN,COS} and handle UNSPEC_FSCALE like
	UNSPEC_FPATAN.

	* gcc.dg/builtins-22.c: New test case.
	* gcc.dg/i386-387-1.c: Update to test exp.
	* gcc.dg/i386-387-2.c: Likewise.

From-SVN: r67973