https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106602
--- Comment #21 from Vineet Gupta <vineetg at rivosinc dot com> ---
I've been experimenting with
(define_predicate "consecutive_bits_operand"
(match_code "const_int")
{
unsigned HOST_WIDE_INT val = UINTVAL (op);
if (exact_log2 ((val >> ctz_hwi (val)) + 1) < 0)
return false;
return true;
})
(define_split
[(set (match_operand:DI 0 "register_operand")
(and:DI (match_operand:DI 1 "register_operand")
(match_operand:DI 2 "consecutive_bits_operand")))
(clobber (match_operand:DI 3 "register_operand"))]
"TARGET_64BIT"
[(set (match_dup 3)
(lshiftrt:DI (match_dup 1) (match_dup 4)))
(set (match_dup 3)
(ashift:DI (match_dup 3) (match_dup 5)))
(set (match_dup 0)
(lshiftrt:DI (match_dup 3) (match_dup 6)))]
{
unsigned HOST_WIDE_INT mask = UINTVAL (operands[2]);
int r = ctz_hwi (mask);
int l = clz_hwi (mask);
operands[4] = GEN_INT (r);
operands[5] = GEN_INT (r+l);
operands[6] = GEN_INT (l);
})
However
try_combine
recog_for_combine
recog_for_combine_1
recog( )
is failing and we get "Failed to recognize..."
(gdb) call debug_rtx(x1)
(set (reg:DI 75)
(and:DI (reg:DI 76)
(const_int 274877906880 [0x3fffffffc0])))
I can't step through recog() cpp code since gen* insert #line for md file and
gdb steps through unrelated md code. FWIW cc1 is being built with -g3 -O0
