https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118174
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
So I think
int gsum;
int
foo (signed char *p1, signed char *p2)
{
int sum = 0;
for (int i = 0; i < 32; i++)
sum += __builtin_abs (p1[i] - p2[i]);
gsum = sum;
}
is handled correctly(?) (btw, I see signed ops):
foo:
.LFB0:
.cfi_startproc
mov x2, x0
adrp x3, .LANCHOR0
ldp q0, q31, [x1]
ldp q1, q28, [x2]
sabdl2 v29.8h, v1.16b, v0.16b
sabdl2 v30.8h, v28.16b, v31.16b
sabal v29.8h, v1.8b, v0.8b
sabal v30.8h, v28.8b, v31.8b
saddlp v29.4s, v29.8h
sadalp v29.4s, v30.8h
addv s29, v29.4s
str s29, [x3, #:lo12:.LANCHOR0]
in fact the expand dump shows
;; _88 = .REDUC_PLUS (vect_patt_26.11_80); [tail call]
(insn 14 13 15 (set (reg:V16QI 115 [ vect__3.6_72 ])
(mem:V16QI (plus:DI (reg/v/f:DI 108 [ p1 ])
(const_int 16 [0x10])) [0 MEM <vector(16) signed char> [(signed
char *)p1_13(D) + 16B]+0 S16 A8])) "t.c":7:29 -1
(nil))
...
;; return _88;
(insn 28 27 29 (set (reg:V16QI 125 [ vect__3.6_72 ])
(mem:V16QI (plus:DI (reg/v/f:DI 108 [ p1 ])
(const_int 16 [0x10])) [0 MEM <vector(16) signed char> [(signed
char *)p1_13(D) + 16B]+0 S16 A8])) "t.c":7:29 -1
(nil))
...
so we're indeed expanding the chain twice somehow. One obvious issue is that
we're failing to skip expanding the call itself because we're pre-empted by
tail-call handling (of course it isn't a "tailcall", but still).
So not applying TER to tail-call direct internal calls fixes this (the
alternative to not tail-call internal functions is more invasive at this
point).
Testing the obvious patch.
