PR tree-optimization/51581
	* expr.h (choose_multiplier): New prototype.
	* expmed.c (choose_multiplier): No longer static.
	Change multiplier_ptr from rtx * to UHWI *.
	(expand_divmod): Adjust callers.
	* tree-vect-patterns.c (vect_recog_sdivmod_pow2_pattern):
	Renamed to...
	(vect_recog_divmod_pattern): ... this.  Pass bb_vinfo as last
	argument to new_stmt_vec_info.  Attempt to optimize also divisions
	by non-pow2 constants if integer vector division isn't supported.
	* tree-vect-stmts.c (vect_analyze_stmt): If node != NULL,
	don't look at pattern stmts and sequences.

	* gcc.c-torture/execute/pr51581-1.c: New test.
	* gcc.c-torture/execute/pr51581-2.c: New test.
	* gcc.dg/vect/pr51581-1.c: New test.
	* gcc.dg/vect/pr51581-2.c: New test.
	* gcc.dg/vect/pr51581-3.c: New test.
	* gcc.target/i386/avx-pr51581-1.c: New test.
	* gcc.target/i386/avx-pr51581-2.c: New test.
	* gcc.target/i386/avx2-pr51581-1.c: New test.
	* gcc.target/i386/avx2-pr51581-2.c: New test.
	* gcc.dg/vect/slp-26.c (main1): Divide by 0x8031 instead of 3.

From-SVN: r188656