[SLP] Alternation with div/rem introduces potential UB

[aelovikov-intel]

Bugzilla Link	44559
Resolution	FIXED
Resolved on	Jan 22, 2020 16:11
Version	trunk
OS	All
Blocks	#43900
CC	@alexey-bataev,@zmodem,@RKSimon

Extended Description

Fix is uploaded in https://reviews.llvm.org/D72740 and the current miscompilation is captured with a test in https://reviews.llvm.org/D72739.

Creating this bug report as per request in D72740 to ensure backporting to 10.0.

[zmodem]

Cherry-picked those two in d64ca7a and 029140e, respectively.