re PR target/70873 ([7 Regressio] 20% performance regression at 482.sphinx3 after...

re PR target/70873 ([7 Regressio] 20% performance regression at 482.sphinx3 after r235442 with -O2 -m32 on Haswell.)

	PR target/70873
	* config/i386/i386-protos.h (ix86_standard_x87sse_constant_load_p):
	New prototype.
	* config/i386/i386.c (ix86_standard_x87sse_constant_load_p): New.
	* config/i386/i386.md (push mem splitter): Use find_constant_src in
	the splitter condition.
	(FP load splitter): Use ix86_standard_x87sse_constant_load_p in
	the splitter condition.
	(FP float_extend load splitter): Ditto.

From-SVN: r235936