2 Commits

Author	SHA1	Message	Date
Roman Lebedev	0727e2b90c	[DAGCombiner][X86][AArch64] Generalize `A-(A&B)`->`A&(~B)` fold (PR44448) ... The fold 'A - (A & (B - 1))' -> 'A & (0 - B)' added in 8dab0a4a7d is too specific. It should/can just be 'A - (A & B)' -> 'A & (~B)' Even if we don't manage to fold `~` into B, we have likely formed `ANDN` node. Also, this way there's less similar-but-duplicate folds. Name: X - (X & Y) -> X & (~Y) %o = and i32 %X, %Y %r = sub i32 %X, %o => %n = xor i32 %Y, -1 %r = and i32 %X, %n https://rise4fun.com/Alive/kOUl See https://bugs.llvm.org/show_bug.cgi?id=44448 https://reviews.llvm.org/D71499	2020-01-03 17:55:47 +03:00
Roman Lebedev	473deaf34b	[NFC][X86][AArch64] Add 'A - (A & B)' pattern tests (PR44448) ... The fold 'A - (A & (B - 1))' -> 'A & (0 - B)' added in 8dab0a4a7d is too specific. It should just be 'A - (A & B)' -> 'A & (~B)' Name: X - (X & Y) -> X & (~Y) %o = and i32 %X, %Y %r = sub i32 %X, %o => %n = xor i32 %Y, -1 %r = and i32 %X, %n https://rise4fun.com/Alive/kOUl See https://bugs.llvm.org/show_bug.cgi?id=44448 https://reviews.llvm.org/D71499	2020-01-03 17:55:46 +03:00