...

1. xalancbmk's bitset implementation has a redundant bit clear before setting the same bit.  This can be fixed in a generic way with an additional logical simplification pattern 
2. bext can be used to extract a single bit, storing the result into an SImode object, even for rv64 since bits 1..63 will be zero'd by the (&1) operation in the bext specification.
3. ~(1 << N) & C can be safely used for a 32bit object on rv64 when C has 33 or more leading zeros
4. (1 << N) | C and (1 << N) ^ C can be safely used when the logical XOR/IOR is done in DImode since we don't have to worry about sign-extending a DImode object
5. An explicit extension of SImode (1 << N) to DImode can be handled with a simple bset with x0 as a source operand
6. Occasionally GCC will use a "zero_extract" as a destination for some bifield insertions which can be handled with bset/bclr
7. When the shift count is masked such that we know bit 31 is not changed we can more aggressively generate Zbs instructions.

Stakeholders/Partners

RISE:

...