A silly little testcase which the vectorizer doesn't vectorize:
unsigned char qa[128];
unsigned char qb[128];
unsigned char qc[128];
unsigned char qd[128];
void autovectqi (void)
{
int i;
for (i = 0; i < 128; i ++)
qd[i] = qa[i] ^ qb[i] + qc[i];
}
Revision 116799 with '-O3 -fomit-frame-pointer -S -dp -ftree-vectorize
-march=prescott' produces:
autovectqi:
xorl %edx, %edx # 54 *movsi_xor [length = 2]
.L2:
movzbl qb(%edx), %eax # 20 *movqi_1/3 [length = 4]
addb qc(%edx), %al # 21 *addqi_1_lea/2 [length = 3]
xorb qa(%edx), %al # 23 *xorqi_1/1 [length = 3]
movb %al, qd(%edx) # 24 *movqi_1/7 [length = 3]
addl $1, %edx # 26 *addsi_1/1 [length = 3]
cmpl $128, %edx # 27 *cmpsi_1_insn/1 [length = 6]
jne .L2 # 28 *jcc_1 [length = 2]
ret # 51 return_internal [length = 1]
If I change 'qb[i] + qc[i]' to e.g. 'qb[i] & qc[i]' the vectorizer works
fine.
;; Function autovectqi (autovectqi)
[snip lots of stuff]
autovecttest.c:11: note: Access function of PHI: {0, +, 1}_1
autovecttest.c:11: note: Analyze phi: qd_23 = PHI <qd_20(4), qd_4(2)>;
autovecttest.c:11: note: virtual phi. skip.
autovecttest.c:11: note: === vect_analyze_operations ===
autovecttest.c:11: note: examining phi: ivtmp.28_1 = PHI <ivtmp.28_2(4),
128(2)>;
autovecttest.c:11: note: examining phi: i_24 = PHI <i_21(4), 0(2)>;
autovecttest.c:11: note: examining phi: qd_23 = PHI <qd_20(4), qd_4(2)>;
autovecttest.c:11: note: ==> examining statement: <L0>:
autovecttest.c:11: note: irrelevant.
autovecttest.c:11: note: ==> examining statement: D.1860_8 = qa[i_24]
autovecttest.c:11: note: num. args = 4 (not unary/binary op).
autovecttest.c:11: note: vect_is_simple_use: operand qa[i_24]
autovecttest.c:11: note: not ssa-name.
autovecttest.c:11: note: use not simple.
autovecttest.c:11: note: ==> examining statement: D.1861_9 = (signed char)
D.1860_8
autovecttest.c:11: note: vect_is_simple_use: operand D.1860_8
autovecttest.c:11: note: def_stmt: D.1860_8 = qa[i_24]
autovecttest.c:11: note: type of def: 2.
autovecttest.c:11: note: no optab.
autovecttest.c:11: note: vect_is_simple_use: operand (signed char) D.1860_8
autovecttest.c:11: note: not ssa-name.
autovecttest.c:11: note: use not simple.
autovecttest.c:11: note: not vectorized: relevant stmt not supported: D.1861_9
= (signed char) D.1860_8
autovecttest.c:11: note: bad operation or unsupported loop bound.
autovecttest.c:11: note: vectorized 0 loops in function.
autovectqi ()
{
unsigned int ivtmp.28;
int pretmp.22;
int i;
unsigned char D.1867;
signed char D.1866;
signed char D.1865;
unsigned char D.1864;
unsigned char D.1863;
unsigned char D.1862;
signed char D.1861;
unsigned char D.1860;
<bb 2>:
# ivtmp.28_1 = PHI <ivtmp.28_2(4), 128(2)>;
# i_24 = PHI <i_21(4), 0(2)>;
<L0>:;
D.1860_8 = qa[i_24];
D.1861_9 = (signed char) D.1860_8;
D.1862_12 = qb[i_24];
D.1863_15 = qc[i_24];
D.1864_16 = D.1863_15 + D.1862_12;
D.1865_17 = (signed char) D.1864_16;
D.1866_18 = D.1865_17 ^ D.1861_9;
D.1867_19 = (unsigned char) D.1866_18;
qd[i_24] = D.1867_19;
i_21 = i_24 + 1;
ivtmp.28_2 = ivtmp.28_1 - 1;
if (ivtmp.28_2 != 0) goto <L5>; else goto <L2>;
<L5>:;
goto <bb 3> (<L0>);
<L2>:;
return;
}
[cut]
--
Rask Ingemann Lambertsen
