> (clrsb:m x)
> Represents the number of redundant leading sign bits in x, represented
> as an integer of mode m, starting at the most significant bit position.
This explanation is just what the NSA instruction (not ever emitted before)
calculates in Xtensa ISA.
gcc/ChangeLog:
* config/xtensa/xtensa.md (clrsbsi2): New insn pattern.
libgcc/ChangeLog:
* config/xtensa/lib1funcs.S (__clrsbsi2): New function.
* config/xtensa/t-xtensa (LIB1ASMFUNCS): Add _clrsbsi2.
29dc90a580