David Majnemer 49775e0173 InstCombine: Don't unconditionally preserve 'nuw' when shrinking constants ...

Consider:
  %add = add nuw i32 %a, -16777216
  %and = and i32 %add, 255

Regardless of whether or not we demand the sign bit of %add, we cannot
replace -16777216 with 2130706432 without also removing 'nuw' from the
instruction.

llvm-svn: 216273

2014-08-22 17:11:04 +00:00

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