On Fri, 2016-12-16 at 17:14 -0600, Segher Boessenkool wrote:
> Please repost. Thanks,
Hi Segher,
Thanks for the review. Attached is an updated patch that should
address the issues you noted.
Bootstrap/regtest in progress on ppc64le -mcpu=power8, ok for trunk if
results are clean?
Thanks,
Aaron
--
Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com
050-2/C113 (507) 253-7520 home: 507/263-0782
IBM Linux Technology Center - PPC Toolchain
Index: gcc/config/rs6000/rs6000-protos.h
===================================================================
--- gcc/config/rs6000/rs6000-protos.h (revision 243799)
+++ gcc/config/rs6000/rs6000-protos.h (working copy)
@@ -78,6 +78,7 @@
extern int expand_block_clear (rtx[]);
extern int expand_block_move (rtx[]);
extern bool expand_block_compare (rtx[]);
+extern bool expand_strn_compare (rtx[]);
extern const char * rs6000_output_load_multiple (rtx[]);
extern bool rs6000_is_valid_mask (rtx, int *, int *, machine_mode);
extern bool rs6000_is_valid_and_mask (rtx, machine_mode);
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 243799)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -19382,7 +19382,388 @@
return true;
}
+/* Generate alignment check and branch code to set up for
+ strncmp when we don't have DI alignment.
+ STRNCMP_LABEL is the label to branch if there is a page crossing.
+ SRC is the string pointer to be examined.
+ BYTES is the max number of bytes to compare. */
+static void
+expand_strncmp_align_check (rtx strncmp_label, rtx src, HOST_WIDE_INT bytes)
+{
+ rtx lab_ref = gen_rtx_LABEL_REF (VOIDmode, strncmp_label);
+ rtx src_check = copy_addr_to_reg (XEXP (src, 0));
+ if (GET_MODE (src_check) == SImode)
+ emit_insn (gen_andsi3 (src_check, src_check, GEN_INT (0xfff)));
+ else
+ emit_insn (gen_anddi3 (src_check, src_check, GEN_INT (0xfff)));
+ rtx cond = gen_reg_rtx (CCmode);
+ emit_move_insn (cond, gen_rtx_COMPARE (CCmode, src_check,
+ GEN_INT (4096 - bytes)));
+ rtx cmp_rtx = gen_rtx_LT (VOIDmode, cond, const0_rtx);
+
+ rtx ifelse = gen_rtx_IF_THEN_ELSE (VOIDmode, cmp_rtx,
+ pc_rtx, lab_ref);
+ rtx j = emit_jump_insn (gen_rtx_SET (pc_rtx, ifelse));
+ JUMP_LABEL (j) = strncmp_label;
+ LABEL_NUSES (strncmp_label) += 1;
+}
+
+/* Expand a string compare operation with length, and return
+ true if successful. Return false if we should let the
+ compiler generate normal code, probably a strncmp call.
+
+ OPERANDS[0] is the target (result).
+ OPERANDS[1] is the first source.
+ OPERANDS[2] is the second source.
+ OPERANDS[3] is the length.
+ OPERANDS[4] is the alignment in bytes. */
+bool
+expand_strn_compare (rtx operands[])
+{
+ rtx target = operands[0];
+ rtx orig_src1 = operands[1];
+ rtx orig_src2 = operands[2];
+ rtx bytes_rtx = operands[3];
+ rtx align_rtx = operands[4];
+ HOST_WIDE_INT cmp_bytes = 0;
+ rtx src1 = orig_src1;
+ rtx src2 = orig_src2;
+
+ /* If this is not a fixed size compare, just call strncmp. */
+ if (!CONST_INT_P (bytes_rtx))
+ return false;
+
+ /* This must be a fixed size alignment. */
+ if (!CONST_INT_P (align_rtx))
+ return false;
+
+ int base_align = INTVAL (align_rtx);
+ int align1 = MEM_ALIGN (orig_src1) / BITS_PER_UNIT;
+ int align2 = MEM_ALIGN (orig_src2) / BITS_PER_UNIT;
+
+ /* SLOW_UNALIGNED_ACCESS -- don't do unaligned stuff. */
+ if (SLOW_UNALIGNED_ACCESS (word_mode, align1)
+ || SLOW_UNALIGNED_ACCESS (word_mode, align2))
+ return false;
+
+ gcc_assert (GET_MODE (target) == SImode);
+
+ HOST_WIDE_INT bytes = INTVAL (bytes_rtx);
+
+ /* If we have an LE target without ldbrx and word_mode is DImode,
+ then we must avoid using word_mode. */
+ int word_mode_ok = !(!BYTES_BIG_ENDIAN && !TARGET_LDBRX
+ && word_mode == DImode);
+
+ int word_mode_size = GET_MODE_SIZE (word_mode);
+
+ int offset = 0;
+ machine_mode load_mode =
+ select_block_compare_mode (offset, bytes, base_align, word_mode_ok);
+ int load_mode_size = GET_MODE_SIZE (load_mode);
+
+ /* We don't want to generate too much code. Also if bytes is
+ 4096 or larger we always want the library strncmp anyway. */
+ int groups = ROUND_UP (bytes, load_mode_size) / load_mode_size;
+ if (bytes >= 4096 || groups > rs6000_string_compare_inline_limit)
+ return false;
+
+ rtx result_reg = gen_reg_rtx (word_mode);
+ rtx final_move_label = gen_label_rtx ();
+ rtx final_label = gen_label_rtx ();
+ rtx begin_compare_label = NULL;
+
+ if (base_align < 8)
+ {
+ /* Generate code that checks distance to 4k boundary for this case. */
+ begin_compare_label = gen_label_rtx ();
+ rtx strncmp_label = gen_label_rtx ();
+ rtx jmp;
+
+ /* Strncmp for power8 in glibc does this:
+ rldicl r8,r3,0,52
+ cmpldi cr7,r8,4096-16
+ bgt cr7,L(pagecross) */
+
+ if (align1 < 8)
+ expand_strncmp_align_check (strncmp_label, src1, bytes);
+ if (align2 < 8)
+ expand_strncmp_align_check (strncmp_label, src2, bytes);
+
+ /* Now generate the following sequence:
+ - branch to begin_compare
+ - strncmp_label
+ - call to strncmp
+ - branch to final_label
+ - begin_compare_label */
+
+ rtx cmp_ref = gen_rtx_LABEL_REF (VOIDmode, begin_compare_label);
+ jmp = emit_jump_insn (gen_rtx_SET (pc_rtx, cmp_ref));
+ JUMP_LABEL(jmp) = begin_compare_label;
+ LABEL_NUSES (begin_compare_label) += 1;
+ emit_barrier ();
+
+ emit_label (strncmp_label);
+
+ if (!REG_P (XEXP (src1, 0)))
+ {
+ rtx src1_reg = copy_addr_to_reg (XEXP (src1, 0));
+ src1 = replace_equiv_address (src1, src1_reg);
+ }
+
+ if (!REG_P (XEXP (src2, 0)))
+ {
+ rtx src2_reg = copy_addr_to_reg (XEXP (src2, 0));
+ src2 = replace_equiv_address (src2, src2_reg);
+ }
+
+ /* -m32 -mpowerpc64 results in word_mode being DImode even
+ though otherwise it is 32-bit. The length arg to strncmp
+ is a size_t which will be the same size as pointers. */
+ rtx len_rtx;
+ if (TARGET_64BIT)
+ len_rtx = gen_reg_rtx(DImode);
+ else
+ len_rtx = gen_reg_rtx(SImode);
+
+ emit_move_insn (len_rtx, bytes_rtx);
+
+ emit_library_call_value (gen_rtx_SYMBOL_REF (Pmode, "strncmp"),
+ target, LCT_NORMAL, GET_MODE (target), 3,
+ force_reg (Pmode, XEXP (src1, 0)), Pmode,
+ force_reg (Pmode, XEXP (src2, 0)), Pmode,
+ len_rtx, GET_MODE (len_rtx));
+
+ rtx fin_ref = gen_rtx_LABEL_REF (VOIDmode, final_label);
+ jmp = emit_jump_insn (gen_rtx_SET (pc_rtx, fin_ref));
+ JUMP_LABEL (jmp) = final_label;
+ LABEL_NUSES (final_label) += 1;
+ emit_barrier ();
+ emit_label (begin_compare_label);
+ }
+
+ rtx cleanup_label = NULL;
+ rtx tmp_reg_src1 = gen_reg_rtx (word_mode);
+ rtx tmp_reg_src2 = gen_reg_rtx (word_mode);
+
+ /* Generate sequence of ld/ldbrx, cmpb to compare out
+ to the length specified. */
+ while (bytes > 0)
+ {
+ /* Compare sequence:
+ check each 8B with: ld/ld cmpd 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
+ subf subtract for final result
+
+ The last compare can branch around the cleanup code if the
+ result is zero because the strings are exactly equal. */
+ int align = compute_current_alignment (base_align, offset);
+ if (TARGET_EFFICIENT_OVERLAPPING_UNALIGNED)
+ load_mode = select_block_compare_mode (offset, bytes, align,
+ word_mode_ok);
+ else
+ load_mode = select_block_compare_mode (0, bytes, align, word_mode_ok);
+ load_mode_size = GET_MODE_SIZE (load_mode);
+ if (bytes >= load_mode_size)
+ cmp_bytes = load_mode_size;
+ else if (TARGET_EFFICIENT_OVERLAPPING_UNALIGNED)
+ {
+ /* Move this load back so it doesn't go past the end.
+ P8/P9 can do this efficiently. */
+ int extra_bytes = load_mode_size - bytes;
+ cmp_bytes = bytes;
+ if (extra_bytes < offset)
+ {
+ offset -= extra_bytes;
+ cmp_bytes = load_mode_size;
+ bytes = cmp_bytes;
+ }
+ }
+ else
+ /* P7 and earlier can't do the overlapping load trick fast,
+ so this forces a non-overlapping load and a shift to get
+ rid of the extra bytes. */
+ cmp_bytes = bytes;
+
+ src1 = adjust_address (orig_src1, load_mode, offset);
+ src2 = adjust_address (orig_src2, load_mode, offset);
+
+ if (!REG_P (XEXP (src1, 0)))
+ {
+ rtx src1_reg = copy_addr_to_reg (XEXP (src1, 0));
+ src1 = replace_equiv_address (src1, src1_reg);
+ }
+ set_mem_size (src1, cmp_bytes);
+
+ if (!REG_P (XEXP (src2, 0)))
+ {
+ rtx src2_reg = copy_addr_to_reg (XEXP (src2, 0));
+ src2 = replace_equiv_address (src2, src2_reg);
+ }
+ set_mem_size (src2, cmp_bytes);
+
+ do_load_for_compare (tmp_reg_src1, src1, load_mode);
+ do_load_for_compare (tmp_reg_src2, src2, load_mode);
+
+ /* 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. */
+
+ if (load_mode_size < word_mode_size)
+ {
+ /* Rotate left first. */
+ rtx sh = GEN_INT (BITS_PER_UNIT * (word_mode_size - load_mode_size));
+ if (word_mode == DImode)
+ {
+ emit_insn (gen_rotldi3 (tmp_reg_src1, tmp_reg_src1, sh));
+ emit_insn (gen_rotldi3 (tmp_reg_src2, tmp_reg_src2, sh));
+ }
+ else
+ {
+ emit_insn (gen_rotlsi3 (tmp_reg_src1, tmp_reg_src1, sh));
+ emit_insn (gen_rotlsi3 (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);
+ if (word_mode == DImode)
+ {
+ emit_insn (gen_anddi3_mask (tmp_reg_src1, tmp_reg_src1, mask));
+ emit_insn (gen_anddi3_mask (tmp_reg_src2, tmp_reg_src2, mask));
+ }
+ else
+ {
+ emit_insn (gen_andsi3_mask (tmp_reg_src1, tmp_reg_src1, mask));
+ emit_insn (gen_andsi3_mask (tmp_reg_src2, tmp_reg_src2, mask));
+ }
+ }
+
+ int remain = bytes - cmp_bytes;
+
+ rtx dst_label;
+ if (remain > 0)
+ {
+ if (!cleanup_label)
+ cleanup_label = gen_label_rtx ();
+ dst_label = cleanup_label;
+ }
+ else
+ dst_label = final_move_label;
+
+ rtx lab_ref = gen_rtx_LABEL_REF (VOIDmode, dst_label);
+ rtx cond = gen_reg_rtx (CCmode);
+
+ if (remain == 0)
+ {
+ /* For the last chunk, subf. also
+ generates the zero result we need. */
+ rtx tmp = gen_rtx_MINUS (word_mode, tmp_reg_src1, tmp_reg_src2);
+ rs6000_emit_dot_insn (result_reg, tmp, 1, cond);
+ }
+ else
+ emit_move_insn (cond, gen_rtx_COMPARE (CCmode,
+ tmp_reg_src1, tmp_reg_src2));
+
+ rtx cmp_rtx;
+ if (remain > 0)
+ cmp_rtx = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+ else
+ cmp_rtx = gen_rtx_EQ (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;
+ bytes -= cmp_bytes;
+ }
+
+ if (cleanup_label)
+ emit_label (cleanup_label);
+
+ /* 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
+ subf subtract for final result
+ */
+
+ rtx cmpb_diff = gen_reg_rtx (word_mode);
+ rtx cmpb_zero = gen_reg_rtx (word_mode);
+ rtx rot_amt = gen_reg_rtx (word_mode);
+ rtx zero_reg = gen_reg_rtx (word_mode);
+
+ rtx rot1_1 = gen_reg_rtx(word_mode);
+ rtx rot1_2 = gen_reg_rtx(word_mode);
+ rtx rot2_1 = gen_reg_rtx(word_mode);
+ rtx rot2_2 = gen_reg_rtx(word_mode);
+
+ if (word_mode == SImode)
+ {
+ emit_insn (gen_cmpbsi3 (cmpb_diff, tmp_reg_src1, tmp_reg_src2));
+ emit_insn (gen_movsi (zero_reg, GEN_INT(0)));
+ emit_insn (gen_cmpbsi3 (cmpb_zero, tmp_reg_src1, 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_addsi3 (rot_amt, rot_amt, GEN_INT (8)));
+ emit_insn (gen_rotlsi3 (rot1_1, tmp_reg_src1,
+ gen_lowpart (SImode, rot_amt)));
+ emit_insn (gen_andsi3_mask (rot1_2, rot1_1, GEN_INT(0xff)));
+ emit_insn (gen_rotlsi3 (rot2_1, tmp_reg_src2,
+ gen_lowpart (SImode, rot_amt)));
+ emit_insn (gen_andsi3_mask (rot2_2, rot2_1, GEN_INT(0xff)));
+ emit_insn (gen_subsi3 (result_reg, rot1_2, rot2_2));
+ }
+ else
+ {
+ emit_insn (gen_cmpbdi3 (cmpb_diff, tmp_reg_src1, tmp_reg_src2));
+ emit_insn (gen_movdi (zero_reg, GEN_INT(0)));
+ emit_insn (gen_cmpbdi3 (cmpb_zero, tmp_reg_src1, 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_adddi3 (rot_amt, rot_amt, GEN_INT (8)));
+ emit_insn (gen_rotldi3 (rot1_1, tmp_reg_src1,
+ gen_lowpart (SImode, rot_amt)));
+ emit_insn (gen_anddi3_mask (rot1_2, rot1_1, GEN_INT(0xff)));
+ emit_insn (gen_rotldi3 (rot2_1, tmp_reg_src2,
+ gen_lowpart (SImode, rot_amt)));
+ emit_insn (gen_anddi3_mask (rot2_2, rot2_1, GEN_INT(0xff)));
+ emit_insn (gen_subdi3 (result_reg, rot1_2, rot2_2));
+ }
+
+ emit_label (final_move_label);
+ emit_insn (gen_movsi (target,
+ gen_lowpart (SImode, result_reg)));
+ emit_label (final_label);
+ return true;
+}
+
+
/* Expand a block move operation, and return 1 if successful. Return 0
if we should let the compiler generate normal code.
Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md (revision 243799)
+++ gcc/config/rs6000/rs6000.md (working copy)
@@ -117,6 +117,7 @@
UNSPEC_BPERM
UNSPEC_COPYSIGN
UNSPEC_PARITY
+ UNSPEC_CMPB
UNSPEC_FCTIW
UNSPEC_FCTID
UNSPEC_LFIWAX
@@ -2316,6 +2317,13 @@
"prty<wd> %0,%1"
[(set_attr "type" "popcnt")])
+(define_insn "cmpb<mode>3"
+ [(set (match_operand:GPR 0 "gpc_reg_operand" "=r")
+ (unspec:GPR [(match_operand:GPR 1 "gpc_reg_operand" "r")
+ (match_operand:GPR 2 "gpc_reg_operand" "r")] UNSPEC_CMPB))]
+ "TARGET_CMPB"
+ "cmpb %0,%1,%2"
+ [(set_attr "type" "cmp")])
;; Since the hardware zeros the upper part of the register, save generating the
;; AND immediate if we are converting to unsigned
@@ -8844,7 +8852,7 @@
FAIL;
}")
-;; String/block compare insn.
+;; String compare N insn.
;; Argument 0 is the target (result)
;; Argument 1 is the destination
;; Argument 2 is the source
@@ -8851,6 +8859,27 @@
;; Argument 3 is the length
;; Argument 4 is the alignment
+(define_expand "cmpstrnsi"
+ [(parallel [(set (match_operand:SI 0)
+ (compare:SI (match_operand:BLK 1)
+ (match_operand:BLK 2)))
+ (use (match_operand:SI 3))
+ (use (match_operand:SI 4))])]
+ "TARGET_CMPB && (BYTES_BIG_ENDIAN || TARGET_LDBRX)"
+{
+ if (expand_strn_compare (operands))
+ DONE;
+ else
+ FAIL;
+})
+
+;; Block compare insn.
+;; Argument 0 is the target (result)
+;; Argument 1 is the destination
+;; Argument 2 is the source
+;; Argument 3 is the length
+;; Argument 4 is the alignment
+
(define_expand "cmpmemsi"
[(parallel [(set (match_operand:SI 0)
(compare:SI (match_operand:BLK 1)
Index: gcc/config/rs6000/rs6000.opt
===================================================================
--- gcc/config/rs6000/rs6000.opt (revision 243799)
+++ gcc/config/rs6000/rs6000.opt (working copy)
@@ -337,6 +337,10 @@
Target Report Var(rs6000_block_compare_inline_limit) Init(5) RejectNegative Joined UInteger Save
Specify the maximum number pairs of load instructions that should be generated inline for the compare. If the number needed exceeds the limit, a call to memcmp will be generated instead.
+mstring-compare-inline-limit=
+Target Report Var(rs6000_string_compare_inline_limit) Init(8) RejectNegative Joined UInteger Save
+Specify the maximum number pairs of load instructions that should be generated inline for the compare. If the number needed exceeds the limit, a call to strncmp will be generated instead.
+
misel
Target Report Mask(ISEL) Var(rs6000_isa_flags)
Generate isel instructions.
