2 Commits

Author	SHA1	Message	Date
Tim Northover	0415b1810b	InstCombine: allow unmasked icmps to be combined with logical ops ... "(icmp op i8 A, B)" is equivalent to "(icmp op i8 (A & 0xff), B)" as a degenerate case. Allowing this as a "masked" comparison when analysing "(icmp) &/| (icmp)" allows us to combine them in more cases. rdar://problem/7625728 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189931 91177308-0d34-0410-b5e6-96231b3b80d8	2013-09-04 11:57:17 +00:00
Tim Northover	7bfabdac4e	InstCombine: look for masked compares with subset relation ... Even in cases which aren't universally optimisable like "(A & B) != 0 && (A & C) != 0", the masks can make one of the comparisons completely redundant. In this case, since we've gone to the effort of spotting masked comparisons we should combine them. rdar://problem/7625728 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189930 91177308-0d34-0410-b5e6-96231b3b80d8	2013-09-04 11:57:13 +00:00