re PR tree-optimization/79345 (passing yet-uninitialized member as argument to base class constructor should warn (-Wunitialized))

	PR tree-optimization/79345
	* gensupport.h (struct pattern_stats): Add min_scratch_opno field.
	* gensupport.c (get_pattern_stats_1) <case MATCH_SCRATCH>: Update it.
	(get_pattern_stats): Initialize it.
	* genemit.c (gen_expand): Verify match_scratch numbers come after
	match_operand/match_dup numbers.
	* config/i386/i386.md (<s>mul<mode>3_highpart): Swap match_dup and
	match_scratch numbers.
	* config/i386/sse.md (avx2_gathersi<mode>, avx2_gatherdi<mode>):
	Likewise.
	* config/s390/s390.md (trunctdsd2): Likewise.

From-SVN: r245833