gcc_assert (mode == E_QImode);
emit_move_insn (reg, mem);
break;
-
+
default:
gcc_unreachable ();
break;
{
if (GET_MODE_SIZE (GET_MODE (bytes_rtx)) > GET_MODE_SIZE (word_mode))
/* Do not expect length longer than word_mode. */
- return false;
+ return false;
else if (GET_MODE_SIZE (GET_MODE (bytes_rtx)) < GET_MODE_SIZE (word_mode))
{
bytes_rtx = force_reg (GET_MODE (bytes_rtx), bytes_rtx);
rtx j;
/* Example of generated code for 35 bytes aligned 1 byte.
-
+
mtctr 8
li 6,0
li 5,8
popcntd 9,9
subfe 10,10,10
or 9,9,10
-
+
Compiled with -fno-reorder-blocks for clarity. */
/* Structure of what we're going to do:
if (!bytes_is_const)
{
/* If we're dealing with runtime length, we have to check if
- it's zero after the loop. When length is known at compile
+ it's zero after the loop. When length is known at compile
time the no-remainder condition is dealt with above. By
doing this after cleanup_label, we also deal with the
case where length is 0 at the start and we bypass the
rtx tmp_reg_src1 = gen_reg_rtx (word_mode);
rtx tmp_reg_src2 = gen_reg_rtx (word_mode);
/* P7/P8 code uses cond for subfc. but P9 uses
- it for cmpld which needs CCUNSmode. */
+ it for cmpld which needs CCUNSmode. */
rtx cond;
if (TARGET_P9_MISC)
cond = gen_reg_rtx (CCUNSmode);
emit_label (convert_label);
/* We need to produce DI result from sub, then convert to target SI
- while maintaining <0 / ==0 / >0 properties. This sequence works:
+ while maintaining <0 / ==0 / >0 properties. This sequence works:
subfc L,A,B
subfe H,H,H
popcntd L,L
to strcmp/strncmp if we have equality at the end of the inline comparison.
P_CLEANUP_LABEL is a pointer to rtx for a label we generate if we need code
to clean up and generate the final comparison result.
- FINAL_MOVE_LABEL is rtx for a label we can branch to when we can just
+ FINAL_MOVE_LABEL is rtx for a label we can branch to when we can just
set the final result. */
static void
expand_strncmp_gpr_sequence (unsigned HOST_WIDE_INT bytes_to_compare,
while (bytes_to_compare > 0)
{
/* GPR compare sequence:
- check each 8B with: ld/ld cmpd bne
- If equal, use rldicr/cmpb to check for zero byte.
+ check each 8B with: ld/ld/cmpb/cmpb/orc./bne
+
cleanup code at end:
- cmpb get byte that differs
- cmpb look for zero byte
- orc combine
cntlzd get bit of first zero/diff byte
subfic convert for rldcl use
rldcl rldcl extract diff/zero byte
The last compare can branch around the cleanup code if the
result is zero because the strings are exactly equal. */
-
+
unsigned int align = compute_current_alignment (base_align, offset);
load_mode = select_block_compare_mode (offset, bytes_to_compare, align);
load_mode_size = GET_MODE_SIZE (load_mode);
rid of the extra bytes. */
cmp_bytes = bytes_to_compare;
- rtx addr1 = gen_rtx_PLUS (Pmode, src1_addr, GEN_INT (offset));
+ rtx offset_reg = gen_reg_rtx (Pmode);
+ emit_move_insn (offset_reg, GEN_INT (offset));
+
+ rtx addr1 = gen_rtx_PLUS (Pmode, src1_addr, offset_reg);
do_load_for_compare_from_addr (load_mode, tmp_reg_src1, addr1, orig_src1);
- rtx addr2 = gen_rtx_PLUS (Pmode, src2_addr, GEN_INT (offset));
+ rtx addr2 = gen_rtx_PLUS (Pmode, src2_addr, offset_reg);
do_load_for_compare_from_addr (load_mode, tmp_reg_src2, addr2, orig_src2);
/* We must always left-align the data we read, and
clear any bytes to the right that are beyond the string.
Otherwise the cmpb sequence won't produce the correct
- results. The beginning of the compare will be done
- with word_mode so will not have any extra shifts or
- clear rights. */
+ results. However if there is only one byte left, we
+ can just subtract to get the final result so the shifts
+ and clears are not needed. */
- if (load_mode_size < word_mode_size)
- {
- /* Rotate left first. */
- rtx sh = GEN_INT (BITS_PER_UNIT * (word_mode_size - load_mode_size));
- do_rotl3 (tmp_reg_src1, tmp_reg_src1, sh);
- do_rotl3 (tmp_reg_src2, tmp_reg_src2, sh);
- }
+ unsigned HOST_WIDE_INT remain = bytes_to_compare - cmp_bytes;
- if (cmp_bytes < word_mode_size)
+ /* Loading just a single byte is a special case. If we are
+ loading more than that, we have to check whether we are
+ looking at the entire chunk of data. If not, rotate left and
+ clear right so that bytes we aren't supposed to look at are
+ zeroed, and the first byte we are supposed to compare is
+ leftmost. */
+ if (load_mode_size != 1)
{
- /* Now clear right. This plus the rotate can be
- turned into a rldicr instruction. */
- HOST_WIDE_INT mb = BITS_PER_UNIT * (word_mode_size - cmp_bytes);
- rtx mask = GEN_INT (HOST_WIDE_INT_M1U << mb);
- do_and3 (tmp_reg_src1, tmp_reg_src1, mask);
- do_and3 (tmp_reg_src2, tmp_reg_src2, mask);
+ if (load_mode_size < word_mode_size)
+ {
+ /* Rotate left first. */
+ rtx sh = GEN_INT (BITS_PER_UNIT
+ * (word_mode_size - load_mode_size));
+ do_rotl3 (tmp_reg_src1, tmp_reg_src1, sh);
+ do_rotl3 (tmp_reg_src2, tmp_reg_src2, sh);
+ }
+
+ if (cmp_bytes < word_mode_size)
+ {
+ /* Now clear right. This plus the rotate can be
+ turned into a rldicr instruction. */
+ HOST_WIDE_INT mb = BITS_PER_UNIT * (word_mode_size - cmp_bytes);
+ rtx mask = GEN_INT (HOST_WIDE_INT_M1U << mb);
+ do_and3 (tmp_reg_src1, tmp_reg_src1, mask);
+ do_and3 (tmp_reg_src2, tmp_reg_src2, mask);
+ }
}
/* Cases to handle. A and B are chunks of the two strings.
A == B: branch to result 0.
A != B: cleanup code to compute result. */
- unsigned HOST_WIDE_INT remain = bytes_to_compare - cmp_bytes;
-
rtx dst_label;
if (remain > 0 || equality_compare_rest)
{
/* Branch to end and produce result of 0. */
dst_label = final_move_label;
- rtx lab_ref = gen_rtx_LABEL_REF (VOIDmode, dst_label);
- rtx cond = gen_reg_rtx (CCmode);
+ if (load_mode_size == 1)
+ {
+ /* Special case for comparing just single byte. */
+ if (equality_compare_rest)
+ {
+ /* Use subf./bne to branch to final_move_label if the
+ byte differs, otherwise fall through to the strncmp
+ call. We must also check for a zero byte here as we
+ must not make the library call if this is the end of
+ the string. */
+
+ rtx lab_ref = gen_rtx_LABEL_REF (VOIDmode, final_move_label);
+ rtx cond = gen_reg_rtx (CCmode);
+ rtx diff_rtx = gen_rtx_MINUS (word_mode,
+ tmp_reg_src1, tmp_reg_src2);
+ rs6000_emit_dot_insn (result_reg, diff_rtx, 2, cond);
+ rtx cmp_rtx = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+
+ rtx ifelse = gen_rtx_IF_THEN_ELSE (VOIDmode, cmp_rtx,
+ lab_ref, pc_rtx);
+ rtx j = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse));
+ JUMP_LABEL (j) = final_move_label;
+ LABEL_NUSES (final_move_label) += 1;
- /* Always produce the 0 result, it is needed if
- cmpb finds a 0 byte in this chunk. */
- rtx tmp = gen_rtx_MINUS (word_mode, tmp_reg_src1, tmp_reg_src2);
- rs6000_emit_dot_insn (result_reg, tmp, 1, cond);
+ /* Check for zero byte here before fall through to
+ library call. This catches the case where the
+ strings are equal and end in a zero byte at this
+ position. */
- rtx cmp_rtx;
- if (remain == 0 && !equality_compare_rest)
- cmp_rtx = gen_rtx_EQ (VOIDmode, cond, const0_rtx);
- else
- cmp_rtx = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+ rtx cond0 = gen_reg_rtx (CCmode);
+ emit_move_insn (cond0, gen_rtx_COMPARE (CCmode, tmp_reg_src1,
+ const0_rtx));
- rtx ifelse = gen_rtx_IF_THEN_ELSE (VOIDmode, cmp_rtx,
- lab_ref, pc_rtx);
- rtx j = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse));
- JUMP_LABEL (j) = dst_label;
- LABEL_NUSES (dst_label) += 1;
+ rtx cmp0eq_rtx = gen_rtx_EQ (VOIDmode, cond0, const0_rtx);
- if (remain > 0 || equality_compare_rest)
+ rtx ifelse0 = gen_rtx_IF_THEN_ELSE (VOIDmode, cmp0eq_rtx,
+ lab_ref, pc_rtx);
+ rtx j0 = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse0));
+ JUMP_LABEL (j0) = final_move_label;
+ LABEL_NUSES (final_move_label) += 1;
+ }
+ else
+ {
+ /* This is the last byte to be compared so we can use
+ subf to compute the final result and branch
+ unconditionally to final_move_label. */
+
+ do_sub3 (result_reg, tmp_reg_src1, tmp_reg_src2);
+
+ rtx fin_ref = gen_rtx_LABEL_REF (VOIDmode, final_move_label);
+ rtx j = emit_jump_insn (gen_rtx_SET (pc_rtx, fin_ref));
+ JUMP_LABEL (j) = final_move_label;
+ LABEL_NUSES (final_move_label) += 1;
+ emit_barrier ();
+ }
+ }
+ else
{
- /* Generate a cmpb to test for a 0 byte and branch
- to final result if found. */
rtx cmpb_zero = gen_reg_rtx (word_mode);
- rtx lab_ref_fin = gen_rtx_LABEL_REF (VOIDmode, final_move_label);
- rtx condz = gen_reg_rtx (CCmode);
+ rtx cmpb_diff = gen_reg_rtx (word_mode);
rtx zero_reg = gen_reg_rtx (word_mode);
+ rtx lab_ref = gen_rtx_LABEL_REF (VOIDmode, dst_label);
+ rtx cond = gen_reg_rtx (CCmode);
+
emit_move_insn (zero_reg, GEN_INT (0));
+ do_cmpb3 (cmpb_diff, tmp_reg_src1, tmp_reg_src2);
do_cmpb3 (cmpb_zero, tmp_reg_src1, zero_reg);
+ rtx not_diff = gen_rtx_NOT (word_mode, cmpb_diff);
+ rtx orc_rtx = gen_rtx_IOR (word_mode, not_diff, cmpb_zero);
- if (cmp_bytes < word_mode_size)
- {
- /* Don't want to look at zero bytes past end. */
- HOST_WIDE_INT mb =
- BITS_PER_UNIT * (word_mode_size - cmp_bytes);
- rtx mask = GEN_INT (HOST_WIDE_INT_M1U << mb);
- do_and3 (cmpb_zero, cmpb_zero, mask);
- }
+ rs6000_emit_dot_insn (result_reg, orc_rtx, 2, cond);
- emit_move_insn (condz, gen_rtx_COMPARE (CCmode, cmpb_zero, zero_reg));
- rtx cmpnz_rtx = gen_rtx_NE (VOIDmode, condz, const0_rtx);
- rtx ifelse = gen_rtx_IF_THEN_ELSE (VOIDmode, cmpnz_rtx,
- lab_ref_fin, pc_rtx);
- rtx j2 = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse));
- JUMP_LABEL (j2) = final_move_label;
- LABEL_NUSES (final_move_label) += 1;
+ rtx cmp_rtx;
+ if (remain == 0 && !equality_compare_rest)
+ cmp_rtx = gen_rtx_EQ (VOIDmode, cond, const0_rtx);
+ else
+ cmp_rtx = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+ rtx ifelse = gen_rtx_IF_THEN_ELSE (VOIDmode, cmp_rtx,
+ lab_ref, pc_rtx);
+ rtx j = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse));
+ JUMP_LABEL (j) = dst_label;
+ LABEL_NUSES (dst_label) += 1;
}
offset += cmp_bytes;
return;
}
-/* Generate the sequence of compares for strcmp/strncmp using vec/vsx
+/* Generate the sequence of compares for strcmp/strncmp using vec/vsx
instructions.
BYTES_TO_COMPARE is the number of bytes to be compared.
to strcmp/strncmp if we have equality at the end of the inline comparison.
P_CLEANUP_LABEL is a pointer to rtx for a label we generate if we need code to clean up
and generate the final comparison result.
- FINAL_MOVE_LABEL is rtx for a label we can branch to when we can just
+ FINAL_MOVE_LABEL is rtx for a label we can branch to when we can just
set the final result. */
static void
expand_strncmp_vec_sequence (unsigned HOST_WIDE_INT bytes_to_compare,
bne 6,.Lmismatch
Use the overlapping compare trick for the last block if it is
- less than 16 bytes.
+ less than 16 bytes.
*/
load_mode = V16QImode;
load_mode_size = GET_MODE_SIZE (load_mode);
-
+
if (bytes_to_compare >= load_mode_size)
cmp_bytes = load_mode_size;
else
if (branch_to_cleanup)
{
/* Branch to cleanup code, otherwise fall through to do more
- compares. P8 and P9 use different CR bits because on P8
+ compares. P8 and P9 use different CR bits because on P8
we are looking at the result of a comparsion vs a
register of zeroes so the all-true condition means no
- difference or zero was found. On P9, vcmpnezb sets a byte
+ difference or zero was found. On P9, vcmpnezb sets a byte
to 0xff if there is a mismatch or zero, so the all-false
condition indicates we found no difference or zero. */
if (!cleanup_label)
}
else
{
- /* Branch to final return or fall through to cleanup,
+ /* Branch to final return or fall through to cleanup,
result is already set to 0. */
dst_label = final_move_label;
if (TARGET_P9_VECTOR)
/* Generate the final sequence that identifies the differing
byte and generates the final result, taking into account
zero bytes:
-
- cmpb cmpb_result1, src1, src2
- cmpb cmpb_result2, src1, zero
- orc cmpb_result1, cmp_result1, cmpb_result2
+
cntlzd get bit of first zero/diff byte
addi convert for rldcl use
rldcl rldcl extract diff/zero byte
emit_final_str_compare_gpr (rtx str1, rtx str2, rtx result)
{
machine_mode m = GET_MODE (str1);
- rtx cmpb_diff = gen_reg_rtx (m);
- rtx cmpb_zero = gen_reg_rtx (m);
rtx rot_amt = gen_reg_rtx (m);
- rtx zero_reg = gen_reg_rtx (m);
rtx rot1_1 = gen_reg_rtx (m);
rtx rot1_2 = gen_reg_rtx (m);
if (m == SImode)
{
- emit_insn (gen_cmpbsi3 (cmpb_diff, str1, str2));
- emit_insn (gen_movsi (zero_reg, GEN_INT (0)));
- emit_insn (gen_cmpbsi3 (cmpb_zero, str1, zero_reg));
- emit_insn (gen_one_cmplsi2 (cmpb_diff,cmpb_diff));
- emit_insn (gen_iorsi3 (cmpb_diff, cmpb_diff, cmpb_zero));
- emit_insn (gen_clzsi2 (rot_amt, cmpb_diff));
+ emit_insn (gen_clzsi2 (rot_amt, result));
emit_insn (gen_addsi3 (rot_amt, rot_amt, GEN_INT (8)));
emit_insn (gen_rotlsi3 (rot1_1, str1,
gen_lowpart (SImode, rot_amt)));
}
else if (m == DImode)
{
- emit_insn (gen_cmpbdi3 (cmpb_diff, str1, str2));
- emit_insn (gen_movdi (zero_reg, GEN_INT (0)));
- emit_insn (gen_cmpbdi3 (cmpb_zero, str1, zero_reg));
- emit_insn (gen_one_cmpldi2 (cmpb_diff,cmpb_diff));
- emit_insn (gen_iordi3 (cmpb_diff, cmpb_diff, cmpb_zero));
- emit_insn (gen_clzdi2 (rot_amt, cmpb_diff));
+ emit_insn (gen_clzdi2 (rot_amt, result));
emit_insn (gen_adddi3 (rot_amt, rot_amt, GEN_INT (8)));
emit_insn (gen_rotldi3 (rot1_1, str1,
gen_lowpart (SImode, rot_amt)));
}
else
gcc_unreachable ();
-
+
return;
}
lbzx 10,28,9 # use that offset to load differing byte
lbzx 3,29,9
subf 3,3,10 # subtract for final result
-
+
P9:
vclzlsbb # counts trailing bytes with lsb=0
- vextublx # extract differing byte
+ vextublx # extract differing byte
STR1 is the reg rtx for data from string 1.
STR2 is the reg rtx for data from string 2.
gcc_assert (TARGET_P8_VECTOR);
rtx diffix = gen_reg_rtx (DImode);
rtx result_gbbd = gen_reg_rtx (V16QImode);
- /* Since each byte of the input is either 00 or FF, the bytes in
+ /* Since each byte of the input is either 00 or FF, the bytes in
dw0 and dw1 after vgbbd are all identical to each other. */
emit_insn (gen_p8v_vgbbd (result_gbbd, vec_result));
/* For LE, we shift by 9 and get BA in the low two bytes then CTZ.
else
emit_insn (gen_ctzdi2 (count, diffix));
- /* P8 doesn't have a good solution for extracting one byte from
+ /* P8 doesn't have a good solution for extracting one byte from
a vsx reg like vextublx on P9 so we just compute the offset
of the differing byte and load it from each string. */
do_add3 (off_reg, off_reg, count);
}
/* Expand a string compare operation with length, and return
- true if successful. Return false if we should let the
+ true if successful. Return false if we should let the
compiler generate normal code, probably a strncmp call.
OPERANDS[0] is the target (result).
rtx src1_addr = force_reg (Pmode, XEXP (orig_src1, 0));
rtx src2_addr = force_reg (Pmode, XEXP (orig_src2, 0));
- /* If we have a length, it must be constant. This simplifies things
+ /* If we have a length, it must be constant. This simplifies things
a bit as we don't have to generate code to check if we've exceeded
- the length. Later this could be expanded to handle this case. */
+ the length. Later this could be expanded to handle this case. */
if (!no_length && !CONST_INT_P (bytes_rtx))
return false;
else
bytes = UINTVAL (bytes_rtx);
- /* Is it OK to use vec/vsx for this. TARGET_VSX means we have at
+ /* Is it OK to use vec/vsx for this. TARGET_VSX means we have at
least POWER7 but we use TARGET_EFFICIENT_UNALIGNED_VSX which is
at least POWER8. That way we can rely on overlapping compares to
do the final comparison of less than 16 bytes. Also I do not
rtx final_move_label = gen_label_rtx ();
rtx final_label = gen_label_rtx ();
rtx begin_compare_label = NULL;
-
+
if (base_align < required_align)
{
/* Generate code that checks distance to 4k boundary for this case. */
&cleanup_label, final_move_label);
offset = compare_length;
-
+
if (equality_compare_rest)
{
/* Update pointers past what has been compared already. */
projects / gcc.git / commitdiff