xtensa: Optimize bitwise AND operation with some specific forms of constants
This patch offers several insn-and-split patterns for bitwise AND with
register and constant that can be represented as:
i. 1's least significant N bits and the others 0's (17 <= N <= 31)
ii. 1's most significant N bits and the others 0's (12 <= N <= 31)
iii. M 1's sequence of bits and trailing N 0's bits, that cannot fit into a
"MOVI Ax, simm12" instruction (1 <= M <= 16, 1 <= N <= 30)
And also offers shortcuts for conditional branch if each of the abovementioned
operations is (not) equal to zero.
gcc/ChangeLog:
* config/xtensa/predicates.md (shifted_mask_operand):
New predicate.
* config/xtensa/xtensa.md (*andsi3_const_pow2_minus_one):
New insn-and-split pattern.
(*andsi3_const_negative_pow2, *andsi3_const_shifted_mask,
*masktrue_const_pow2_minus_one, *masktrue_const_negative_pow2,
*masktrue_const_shifted_mask): Ditto.