Commit Graph

4 Commits

Author SHA1 Message Date
Nadav Rotem
639570c311 It is illegal to transform (sdiv (ashr X c1) c2) -> (sdiv x (2^c1 * c2)),
because C always rounds towards zero.

Thanks Dirk and Ben.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162899 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 11:23:20 +00:00
Benjamin Kramer
aac7c650a6 InstCombine: Guard the transform introduced in r162743 against large ints and non-const shifts.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162751 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 13:08:13 +00:00
Nadav Rotem
a694e2a691 Make sure that we don't call getZExtValue on values > 64 bits.
Thanks Benjamin for noticing this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162749 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 12:23:22 +00:00
Nadav Rotem
9753f0b9b4 Teach InstCombine to canonicalize [SU]div+[AL]shl patterns.
For example:
  %1 = lshr i32 %x, 2
  %2 = udiv i32 %1, 100

rdar://12182093




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 10:01:43 +00:00