+ /// Returns true if the given lane mask is imprecise.
+ ///
+ /// LaneMasks as given by getSubRegIndexLaneMask() have a limited number of
+ /// bits, so for targets with more than 31 disjunct subregister indices there
+ /// may be cases where:
+ /// getSubReg(Reg,A) does not overlap getSubReg(Reg,B)
+ /// but we still have
+ /// (getSubRegIndexLaneMask(A) & getSubRegIndexLaneMask(B)) != 0.
+ /// This function returns true in those cases.
+ static bool isImpreciseLaneMask(unsigned LaneMask) {
+ return LaneMask & 0x80000000u;
+ }
+