3 Commits

Author	SHA1	Message	Date
Sanjay Patel	0d4fd5b668	[InstSimplify] fold sdiv/srem based on compare of dividend and divisor ... This should bring signed div/rem analysis up to the same level as unsigned. We use icmp simplification to determine when the divisor is known greater than the dividend. Each positive test is followed by a negative test to show that we're not overstepping the boundaries of the known bits. There are extra tests for the signed-min-value special cases. Alive proofs: http://rise4fun.com/Alive/WI5 Differential Revision: https://reviews.llvm.org/D37713 llvm-svn: 313264	2017-09-14 14:59:07 +00:00
Sanjay Patel	bb1b1c97fa	[InstSimplify] fix some test names; NFC ... Too much division...the quotient is the answer. llvm-svn: 312943	2017-09-11 20:38:31 +00:00
Sanjay Patel	a36eb77118	[InstSimplify] add tests for possible sdiv/srem simplifications; NFC ... As noted in PR34517, the handling of signed div/rem is not on par with unsigned div/rem. Signed is harder to reason about, but it should be possible to handle at least some of these using the same technique that we use for unsigned: use icmp logic to see if there's a relationship between the quotient and divisor. llvm-svn: 312938	2017-09-11 19:42:41 +00:00