First teach instcombine that sign bit checks only demand the
sign bit, this allows simplify demanded bits to hack on
expressions better.
Second, teach instcombine that ashr is useless if only the
sign bit is demanded.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39880 91177308-0d34-0410-b5e6-96231b3b80d8
This feature is needed in order to support shifts of more than 255 bits
on large integer types. This changes the syntax for llvm assembly to
make shl, ashr and lshr instructions look like a binary operator:
shl i32 %X, 1
instead of
shl i32 %X, i8 1
Additionally, this should help a few passes perform additional optimizations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33776 91177308-0d34-0410-b5e6-96231b3b80d8
