llvm-project

aeaea7a5 - InstCombine: Fold bitcast of vector with constant to scalar (#179042)

InstCombine: Fold bitcast of vector with constant to scalar (#179042) Fold bitcast (select cond, val, const) -> select cond, (bitcast val), (bitcast const) Rocm device libs has an unfortunate amount of code that does bithacking on the sign bit of double values by casting to <2 x i32> and operating on the high element. This breaks value tracking optimizations on the fp value. The existing transform would only do this if the input to the select was also a bitcast with a single use, and if it didn't convert between vector and scalar.