* [GCC14 PATCH] LoongArch: Improve cpymemsi expansion [PR109465]
@ 2023-04-12 12:16 Xi Ruoyao
2023-04-19 3:03 ` Lulu Cheng
0 siblings, 1 reply; 3+ messages in thread
From: Xi Ruoyao @ 2023-04-12 12:16 UTC (permalink / raw)
To: gcc-patches; +Cc: Lulu Cheng, WANG Xuerui, Chenghua Xu, Xi Ruoyao
We'd been generating really bad block move sequences which is recently
complained by kernel developers who tried __builtin_memcpy. To improve
it:
1. Take the advantage of -mno-strict-align. When it is set, set mode
size to UNITS_PER_WORD regardless of the alignment.
2. Half the mode size when (block size) % (mode size) != 0, instead of
falling back to ld.bu/st.b at once.
3. Limit the length of block move sequence considering the number of
instructions, not the size of block. When -mstrict-align is set and
the block is not aligned, the old size limit for straight-line
implementation (64 bytes) was definitely too large (we don't have 64
registers anyway).
Bootstrapped and regtested on loongarch64-linux-gnu. Ok for GCC 14?
gcc/ChangeLog:
PR target/109465
* config/loongarch/loongarch-protos.h
(loongarch_expand_block_move): Add a parameter as alignment RTX.
* config/loongarch/loongarch.h:
(LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER): Remove.
(LARCH_MAX_MOVE_BYTES_STRAIGHT): Remove.
(LARCH_MAX_MOVE_OPS_PER_LOOP_ITER): Define.
(LARCH_MAX_MOVE_OPS_STRAIGHT): Define.
(MOVE_RATIO): Use LARCH_MAX_MOVE_OPS_PER_LOOP_ITER instead of
LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER.
* config/loongarch/loongarch.cc (loongarch_expand_block_move):
Take the alignment from the parameter, but set it to
UNITS_PER_WORD if !TARGET_STRICT_ALIGN. Limit the length of
straight-line implementation with LARCH_MAX_MOVE_OPS_STRAIGHT
instead of LARCH_MAX_MOVE_BYTES_STRAIGHT.
(loongarch_block_move_straight): When there are left-over bytes,
half the mode size instead of falling back to byte mode at once.
(loongarch_block_move_loop): Limit the length of loop body with
LARCH_MAX_MOVE_OPS_PER_LOOP_ITER instead of
LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER.
* config/loongarch/loongarch.md (cpymemsi): Pass the alignment
to loongarch_expand_block_move.
gcc/testsuite/ChangeLog:
PR target/109465
* gcc.target/loongarch/pr109465-1.c: New test.
* gcc.target/loongarch/pr109465-2.c: New test.
* gcc.target/loongarch/pr109465-3.c: New test.
---
gcc/config/loongarch/loongarch-protos.h | 2 +-
gcc/config/loongarch/loongarch.cc | 87 ++++++++++---------
gcc/config/loongarch/loongarch.h | 10 +--
gcc/config/loongarch/loongarch.md | 3 +-
.../gcc.target/loongarch/pr109465-1.c | 9 ++
.../gcc.target/loongarch/pr109465-2.c | 9 ++
.../gcc.target/loongarch/pr109465-3.c | 12 +++
7 files changed, 83 insertions(+), 49 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/loongarch/pr109465-1.c
create mode 100644 gcc/testsuite/gcc.target/loongarch/pr109465-2.c
create mode 100644 gcc/testsuite/gcc.target/loongarch/pr109465-3.c
diff --git a/gcc/config/loongarch/loongarch-protos.h b/gcc/config/loongarch/loongarch-protos.h
index 83df489c7a5..b71b188507a 100644
--- a/gcc/config/loongarch/loongarch-protos.h
+++ b/gcc/config/loongarch/loongarch-protos.h
@@ -95,7 +95,7 @@ extern void loongarch_expand_conditional_trap (rtx);
#endif
extern void loongarch_set_return_address (rtx, rtx);
extern bool loongarch_move_by_pieces_p (unsigned HOST_WIDE_INT, unsigned int);
-extern bool loongarch_expand_block_move (rtx, rtx, rtx);
+extern bool loongarch_expand_block_move (rtx, rtx, rtx, rtx);
extern bool loongarch_do_optimize_block_move_p (void);
extern bool loongarch_expand_ext_as_unaligned_load (rtx, rtx, HOST_WIDE_INT,
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index dfb731fca9d..06fc1cd0604 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -4459,41 +4459,38 @@ loongarch_function_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED,
Assume that the areas do not overlap. */
static void
-loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length)
+loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length,
+ HOST_WIDE_INT delta)
{
- HOST_WIDE_INT offset, delta;
- unsigned HOST_WIDE_INT bits;
+ HOST_WIDE_INT offs, delta_cur;
int i;
machine_mode mode;
rtx *regs;
- bits = MIN (BITS_PER_WORD, MIN (MEM_ALIGN (src), MEM_ALIGN (dest)));
-
- mode = int_mode_for_size (bits, 0).require ();
- delta = bits / BITS_PER_UNIT;
+ HOST_WIDE_INT num_reg = length / delta;
+ for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
+ num_reg += !!(length & delta_cur);
/* Allocate a buffer for the temporary registers. */
- regs = XALLOCAVEC (rtx, length / delta);
+ regs = XALLOCAVEC (rtx, num_reg);
- /* Load as many BITS-sized chunks as possible. Use a normal load if
- the source has enough alignment, otherwise use left/right pairs. */
- for (offset = 0, i = 0; offset + delta <= length; offset += delta, i++)
+ for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur /= 2)
{
- regs[i] = gen_reg_rtx (mode);
- loongarch_emit_move (regs[i], adjust_address (src, mode, offset));
- }
+ mode = int_mode_for_size (delta_cur * BITS_PER_UNIT, 0).require ();
- for (offset = 0, i = 0; offset + delta <= length; offset += delta, i++)
- loongarch_emit_move (adjust_address (dest, mode, offset), regs[i]);
+ for (; offs + delta_cur <= length; offs += delta_cur, i++)
+ {
+ regs[i] = gen_reg_rtx (mode);
+ loongarch_emit_move (regs[i], adjust_address (src, mode, offs));
+ }
+ }
- /* Mop up any left-over bytes. */
- if (offset < length)
+ for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur /= 2)
{
- src = adjust_address (src, BLKmode, offset);
- dest = adjust_address (dest, BLKmode, offset);
- move_by_pieces (dest, src, length - offset,
- MIN (MEM_ALIGN (src), MEM_ALIGN (dest)),
- (enum memop_ret) 0);
+ mode = int_mode_for_size (delta_cur * BITS_PER_UNIT, 0).require ();
+
+ for (; offs + delta_cur <= length; offs += delta_cur, i++)
+ loongarch_emit_move (adjust_address (dest, mode, offs), regs[i]);
}
}
@@ -4523,10 +4520,11 @@ loongarch_adjust_block_mem (rtx mem, HOST_WIDE_INT length, rtx *loop_reg,
static void
loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
- HOST_WIDE_INT bytes_per_iter)
+ HOST_WIDE_INT align)
{
rtx_code_label *label;
rtx src_reg, dest_reg, final_src, test;
+ HOST_WIDE_INT bytes_per_iter = align * LARCH_MAX_MOVE_OPS_PER_LOOP_ITER;
HOST_WIDE_INT leftover;
leftover = length % bytes_per_iter;
@@ -4546,7 +4544,7 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
emit_label (label);
/* Emit the loop body. */
- loongarch_block_move_straight (dest, src, bytes_per_iter);
+ loongarch_block_move_straight (dest, src, bytes_per_iter, align);
/* Move on to the next block. */
loongarch_emit_move (src_reg,
@@ -4563,7 +4561,7 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
/* Mop up any left-over bytes. */
if (leftover)
- loongarch_block_move_straight (dest, src, leftover);
+ loongarch_block_move_straight (dest, src, leftover, align);
else
/* Temporary fix for PR79150. */
emit_insn (gen_nop ());
@@ -4573,25 +4571,32 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
memory reference SRC to memory reference DEST. */
bool
-loongarch_expand_block_move (rtx dest, rtx src, rtx length)
+loongarch_expand_block_move (rtx dest, rtx src, rtx r_length, rtx r_align)
{
- int max_move_bytes = LARCH_MAX_MOVE_BYTES_STRAIGHT;
+ if (!CONST_INT_P (r_length))
+ return false;
+
+ HOST_WIDE_INT length = INTVAL (r_length);
+ if (length > loongarch_max_inline_memcpy_size)
+ return false;
+
+ HOST_WIDE_INT align = INTVAL (r_align);
+
+ if (!TARGET_STRICT_ALIGN || align > UNITS_PER_WORD)
+ align = UNITS_PER_WORD;
- if (CONST_INT_P (length)
- && INTVAL (length) <= loongarch_max_inline_memcpy_size)
+ if (length <= align * LARCH_MAX_MOVE_OPS_STRAIGHT)
{
- if (INTVAL (length) <= max_move_bytes)
- {
- loongarch_block_move_straight (dest, src, INTVAL (length));
- return true;
- }
- else if (optimize)
- {
- loongarch_block_move_loop (dest, src, INTVAL (length),
- LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER);
- return true;
- }
+ loongarch_block_move_straight (dest, src, length, align);
+ return true;
+ }
+
+ if (optimize)
+ {
+ loongarch_block_move_loop (dest, src, length, align);
+ return true;
}
+
return false;
}
diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
index 7151d5cabb3..1bcd144a5d9 100644
--- a/gcc/config/loongarch/loongarch.h
+++ b/gcc/config/loongarch/loongarch.h
@@ -1063,13 +1063,13 @@ typedef struct {
/* The maximum number of bytes that can be copied by one iteration of
a cpymemsi loop; see loongarch_block_move_loop. */
-#define LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER (UNITS_PER_WORD * 4)
+#define LARCH_MAX_MOVE_OPS_PER_LOOP_ITER 4
/* The maximum number of bytes that can be copied by a straight-line
implementation of cpymemsi; see loongarch_block_move_straight. We want
to make sure that any loop-based implementation will iterate at
least twice. */
-#define LARCH_MAX_MOVE_BYTES_STRAIGHT (LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER * 2)
+#define LARCH_MAX_MOVE_OPS_STRAIGHT (LARCH_MAX_MOVE_OPS_PER_LOOP_ITER * 2)
/* The base cost of a memcpy call, for MOVE_RATIO and friends. These
values were determined experimentally by benchmarking with CSiBE.
@@ -1077,7 +1077,7 @@ typedef struct {
#define LARCH_CALL_RATIO 8
/* Any loop-based implementation of cpymemsi will have at least
- LARCH_MAX_MOVE_BYTES_STRAIGHT / UNITS_PER_WORD memory-to-memory
+ LARCH_MAX_MOVE_OPS_PER_LOOP_ITER memory-to-memory
moves, so allow individual copies of fewer elements.
When cpymemsi is not available, use a value approximating
@@ -1088,9 +1088,7 @@ typedef struct {
value of LARCH_CALL_RATIO to take that into account. */
#define MOVE_RATIO(speed) \
- (HAVE_cpymemsi \
- ? LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER / UNITS_PER_WORD \
- : CLEAR_RATIO (speed) / 2)
+ (HAVE_cpymemsi ? LARCH_MAX_MOVE_OPS_PER_LOOP_ITER : CLEAR_RATIO (speed) / 2)
/* For CLEAR_RATIO, when optimizing for size, give a better estimate
of the length of a memset call, but use the default otherwise. */
diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index 628ecc78088..816a943d155 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -2488,7 +2488,8 @@ (define_expand "cpymemsi"
""
{
if (TARGET_DO_OPTIMIZE_BLOCK_MOVE_P
- && loongarch_expand_block_move (operands[0], operands[1], operands[2]))
+ && loongarch_expand_block_move (operands[0], operands[1],
+ operands[2], operands[3]))
DONE;
else
FAIL;
diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-1.c b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
new file mode 100644
index 00000000000..4cd35d13904
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mabi=lp64d -mno-strict-align" } */
+/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
+
+extern char a[], b[];
+void test() { __builtin_memcpy(a, b, 15); }
diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-2.c b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
new file mode 100644
index 00000000000..703eb951c6d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
+/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
+/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
+
+extern long a[], b[];
+void test() { __builtin_memcpy(a, b, 15); }
diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-3.c b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
new file mode 100644
index 00000000000..d6a80659b31
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
+
+/* Three loop iterations each contains 4 st.b, and 3 st.b after the loop */
+/* { dg-final { scan-assembler-times "st\\.b" 7 } } */
+
+/* { dg-final { scan-assembler-not "st\\.h" } } */
+/* { dg-final { scan-assembler-not "st\\.w|stptr\\.w" } } */
+/* { dg-final { scan-assembler-not "st\\.d|stptr\\.d" } } */
+
+extern char a[], b[];
+void test() { __builtin_memcpy(a, b, 15); }
--
2.40.0
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [GCC14 PATCH] LoongArch: Improve cpymemsi expansion [PR109465]
2023-04-12 12:16 [GCC14 PATCH] LoongArch: Improve cpymemsi expansion [PR109465] Xi Ruoyao
@ 2023-04-19 3:03 ` Lulu Cheng
2023-04-19 10:21 ` Pushed: " Xi Ruoyao
0 siblings, 1 reply; 3+ messages in thread
From: Lulu Cheng @ 2023-04-19 3:03 UTC (permalink / raw)
To: Xi Ruoyao, gcc-patches; +Cc: WANG Xuerui, Chenghua Xu
在 2023/4/12 下午8:16, Xi Ruoyao 写道:
> We'd been generating really bad block move sequences which is recently
> complained by kernel developers who tried __builtin_memcpy. To improve
> it:
>
> 1. Take the advantage of -mno-strict-align. When it is set, set mode
> size to UNITS_PER_WORD regardless of the alignment.
> 2. Half the mode size when (block size) % (mode size) != 0, instead of
> falling back to ld.bu/st.b at once.
> 3. Limit the length of block move sequence considering the number of
> instructions, not the size of block. When -mstrict-align is set and
> the block is not aligned, the old size limit for straight-line
> implementation (64 bytes) was definitely too large (we don't have 64
> registers anyway).
>
> Bootstrapped and regtested on loongarch64-linux-gnu. Ok for GCC 14?
/* snip */
>
> static void
> -loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length)
> +loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length,
> + HOST_WIDE_INT delta)
> {
> - HOST_WIDE_INT offset, delta;
> - unsigned HOST_WIDE_INT bits;
> + HOST_WIDE_INT offs, delta_cur;
> int i;
> machine_mode mode;
> rtx *regs;
>
> - bits = MIN (BITS_PER_WORD, MIN (MEM_ALIGN (src), MEM_ALIGN (dest)));
> -
> - mode = int_mode_for_size (bits, 0).require ();
> - delta = bits / BITS_PER_UNIT;
> + HOST_WIDE_INT num_reg = length / delta;
I think comments need to be added here, if it is not chasing the code,
it is not easy to understand.
Otherwise LGTM!
Thanks!
> + for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
> + num_reg += !!(length & delta_cur);
>
> /* Allocate a buffer for the temporary registers. */
> - regs = XALLOCAVEC (rtx, length / delta);
> + regs = XALLOCAVEC (rtx, num_reg);
>
> - /* Load as many BITS-sized chunks as possible. Use a normal load if
> - the source has enough alignment, otherwise use left/right pairs. */
> - for (offset = 0, i = 0; offset + delta <= length; offset += delta, i++)
> + for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur /= 2)
> {
> - regs[i] = gen_reg_rtx (mode);
> - loongarch_emit_move (regs[i], adjust_address (src, mode, offset));
> - }
> + mode = int_mode_for_size (delta_cur * BITS_PER_UNIT, 0).require ();
>
> - for (offset = 0, i = 0; offset + delta <= length; offset += delta, i++)
> - loongarch_emit_move (adjust_address (dest, mode, offset), regs[i]);
> + for (; offs + delta_cur <= length; offs += delta_cur, i++)
> + {
> + regs[i] = gen_reg_rtx (mode);
> + loongarch_emit_move (regs[i], adjust_address (src, mode, offs));
> + }
> + }
>
> - /* Mop up any left-over bytes. */
> - if (offset < length)
> + for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur /= 2)
> {
> - src = adjust_address (src, BLKmode, offset);
> - dest = adjust_address (dest, BLKmode, offset);
> - move_by_pieces (dest, src, length - offset,
> - MIN (MEM_ALIGN (src), MEM_ALIGN (dest)),
> - (enum memop_ret) 0);
> + mode = int_mode_for_size (delta_cur * BITS_PER_UNIT, 0).require ();
> +
> + for (; offs + delta_cur <= length; offs += delta_cur, i++)
> + loongarch_emit_move (adjust_address (dest, mode, offs), regs[i]);
> }
> }
>
> @@ -4523,10 +4520,11 @@ loongarch_adjust_block_mem (rtx mem, HOST_WIDE_INT length, rtx *loop_reg,
>
> static void
> loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
> - HOST_WIDE_INT bytes_per_iter)
> + HOST_WIDE_INT align)
> {
> rtx_code_label *label;
> rtx src_reg, dest_reg, final_src, test;
> + HOST_WIDE_INT bytes_per_iter = align * LARCH_MAX_MOVE_OPS_PER_LOOP_ITER;
> HOST_WIDE_INT leftover;
>
> leftover = length % bytes_per_iter;
> @@ -4546,7 +4544,7 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
> emit_label (label);
>
> /* Emit the loop body. */
> - loongarch_block_move_straight (dest, src, bytes_per_iter);
> + loongarch_block_move_straight (dest, src, bytes_per_iter, align);
>
> /* Move on to the next block. */
> loongarch_emit_move (src_reg,
> @@ -4563,7 +4561,7 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
>
> /* Mop up any left-over bytes. */
> if (leftover)
> - loongarch_block_move_straight (dest, src, leftover);
> + loongarch_block_move_straight (dest, src, leftover, align);
> else
> /* Temporary fix for PR79150. */
> emit_insn (gen_nop ());
> @@ -4573,25 +4571,32 @@ loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT length,
> memory reference SRC to memory reference DEST. */
>
> bool
> -loongarch_expand_block_move (rtx dest, rtx src, rtx length)
> +loongarch_expand_block_move (rtx dest, rtx src, rtx r_length, rtx r_align)
> {
> - int max_move_bytes = LARCH_MAX_MOVE_BYTES_STRAIGHT;
> + if (!CONST_INT_P (r_length))
> + return false;
> +
> + HOST_WIDE_INT length = INTVAL (r_length);
> + if (length > loongarch_max_inline_memcpy_size)
> + return false;
> +
> + HOST_WIDE_INT align = INTVAL (r_align);
> +
> + if (!TARGET_STRICT_ALIGN || align > UNITS_PER_WORD)
> + align = UNITS_PER_WORD;
>
> - if (CONST_INT_P (length)
> - && INTVAL (length) <= loongarch_max_inline_memcpy_size)
> + if (length <= align * LARCH_MAX_MOVE_OPS_STRAIGHT)
> {
> - if (INTVAL (length) <= max_move_bytes)
> - {
> - loongarch_block_move_straight (dest, src, INTVAL (length));
> - return true;
> - }
> - else if (optimize)
> - {
> - loongarch_block_move_loop (dest, src, INTVAL (length),
> - LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER);
> - return true;
> - }
> + loongarch_block_move_straight (dest, src, length, align);
> + return true;
> + }
> +
> + if (optimize)
> + {
> + loongarch_block_move_loop (dest, src, length, align);
> + return true;
> }
> +
> return false;
> }
>
> diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
> index 7151d5cabb3..1bcd144a5d9 100644
> --- a/gcc/config/loongarch/loongarch.h
> +++ b/gcc/config/loongarch/loongarch.h
> @@ -1063,13 +1063,13 @@ typedef struct {
>
> /* The maximum number of bytes that can be copied by one iteration of
> a cpymemsi loop; see loongarch_block_move_loop. */
> -#define LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER (UNITS_PER_WORD * 4)
> +#define LARCH_MAX_MOVE_OPS_PER_LOOP_ITER 4
>
> /* The maximum number of bytes that can be copied by a straight-line
> implementation of cpymemsi; see loongarch_block_move_straight. We want
> to make sure that any loop-based implementation will iterate at
> least twice. */
> -#define LARCH_MAX_MOVE_BYTES_STRAIGHT (LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER * 2)
> +#define LARCH_MAX_MOVE_OPS_STRAIGHT (LARCH_MAX_MOVE_OPS_PER_LOOP_ITER * 2)
>
> /* The base cost of a memcpy call, for MOVE_RATIO and friends. These
> values were determined experimentally by benchmarking with CSiBE.
> @@ -1077,7 +1077,7 @@ typedef struct {
> #define LARCH_CALL_RATIO 8
>
> /* Any loop-based implementation of cpymemsi will have at least
> - LARCH_MAX_MOVE_BYTES_STRAIGHT / UNITS_PER_WORD memory-to-memory
> + LARCH_MAX_MOVE_OPS_PER_LOOP_ITER memory-to-memory
> moves, so allow individual copies of fewer elements.
>
> When cpymemsi is not available, use a value approximating
> @@ -1088,9 +1088,7 @@ typedef struct {
> value of LARCH_CALL_RATIO to take that into account. */
>
> #define MOVE_RATIO(speed) \
> - (HAVE_cpymemsi \
> - ? LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER / UNITS_PER_WORD \
> - : CLEAR_RATIO (speed) / 2)
> + (HAVE_cpymemsi ? LARCH_MAX_MOVE_OPS_PER_LOOP_ITER : CLEAR_RATIO (speed) / 2)
>
> /* For CLEAR_RATIO, when optimizing for size, give a better estimate
> of the length of a memset call, but use the default otherwise. */
> diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
> index 628ecc78088..816a943d155 100644
> --- a/gcc/config/loongarch/loongarch.md
> +++ b/gcc/config/loongarch/loongarch.md
> @@ -2488,7 +2488,8 @@ (define_expand "cpymemsi"
> ""
> {
> if (TARGET_DO_OPTIMIZE_BLOCK_MOVE_P
> - && loongarch_expand_block_move (operands[0], operands[1], operands[2]))
> + && loongarch_expand_block_move (operands[0], operands[1],
> + operands[2], operands[3]))
> DONE;
> else
> FAIL;
> diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-1.c b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
> new file mode 100644
> index 00000000000..4cd35d13904
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
> @@ -0,0 +1,9 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mabi=lp64d -mno-strict-align" } */
> +/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
> +
> +extern char a[], b[];
> +void test() { __builtin_memcpy(a, b, 15); }
> diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-2.c b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
> new file mode 100644
> index 00000000000..703eb951c6d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
> @@ -0,0 +1,9 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
> +/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
> +/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
> +
> +extern long a[], b[];
> +void test() { __builtin_memcpy(a, b, 15); }
> diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-3.c b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
> new file mode 100644
> index 00000000000..d6a80659b31
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
> +
> +/* Three loop iterations each contains 4 st.b, and 3 st.b after the loop */
> +/* { dg-final { scan-assembler-times "st\\.b" 7 } } */
> +
> +/* { dg-final { scan-assembler-not "st\\.h" } } */
> +/* { dg-final { scan-assembler-not "st\\.w|stptr\\.w" } } */
> +/* { dg-final { scan-assembler-not "st\\.d|stptr\\.d" } } */
> +
> +extern char a[], b[];
> +void test() { __builtin_memcpy(a, b, 15); }
^ permalink raw reply [flat|nested] 3+ messages in thread* Pushed: [GCC14 PATCH] LoongArch: Improve cpymemsi expansion [PR109465]
2023-04-19 3:03 ` Lulu Cheng
@ 2023-04-19 10:21 ` Xi Ruoyao
0 siblings, 0 replies; 3+ messages in thread
From: Xi Ruoyao @ 2023-04-19 10:21 UTC (permalink / raw)
To: Lulu Cheng, gcc-patches; +Cc: WANG Xuerui, Chenghua Xu
On Wed, 2023-04-19 at 11:03 +0800, Lulu Cheng wrote:
/* snip */
> > +loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT
> > length,
> > + HOST_WIDE_INT delta)
> > {
> > - HOST_WIDE_INT offset, delta;
> > - unsigned HOST_WIDE_INT bits;
> > + HOST_WIDE_INT offs, delta_cur;
> > int i;
> > machine_mode mode;
> > rtx *regs;
> >
> > - bits = MIN (BITS_PER_WORD, MIN (MEM_ALIGN (src), MEM_ALIGN
> > (dest)));
> > -
> > - mode = int_mode_for_size (bits, 0).require ();
> > - delta = bits / BITS_PER_UNIT;
> > + HOST_WIDE_INT num_reg = length / delta;
>
> I think comments need to be added here, if it is not chasing the code,
> it is not easy to understand.
Pushed r14-70 with the following addition:
+ /* Calculate how many registers we'll need for the block move.
+ We'll emit length / delta move operations with delta as the size
+ first. Then we may still have length % delta bytes not copied.
+ We handle these remaining bytes by move operations with smaller
+ (halfed) sizes. For example, if length = 21 and delta = 8, we'll
+ emit two ld.d/st.d pairs, one ld.w/st.w pair, and one ld.b/st.b
+ pair. For each load/store pair we use a dedicated register to keep
+ the pipeline as populated as possible. */
> Otherwise LGTM!
>
> Thanks!
>
> > + for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
> > + num_reg += !!(length & delta_cur);
> >
> > /* Allocate a buffer for the temporary registers. */
> > - regs = XALLOCAVEC (rtx, length / delta);
> > + regs = XALLOCAVEC (rtx, num_reg);
> >
> > - /* Load as many BITS-sized chunks as possible. Use a normal load
> > if
> > - the source has enough alignment, otherwise use left/right
> > pairs. */
> > - for (offset = 0, i = 0; offset + delta <= length; offset +=
> > delta, i++)
> > + for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur
> > /= 2)
> > {
> > - regs[i] = gen_reg_rtx (mode);
> > - loongarch_emit_move (regs[i], adjust_address (src, mode,
> > offset));
> > - }
> > + mode = int_mode_for_size (delta_cur * BITS_PER_UNIT,
> > 0).require ();
> >
> > - for (offset = 0, i = 0; offset + delta <= length; offset +=
> > delta, i++)
> > - loongarch_emit_move (adjust_address (dest, mode, offset),
> > regs[i]);
> > + for (; offs + delta_cur <= length; offs += delta_cur, i++)
> > + {
> > + regs[i] = gen_reg_rtx (mode);
> > + loongarch_emit_move (regs[i], adjust_address (src, mode,
> > offs));
> > + }
> > + }
> >
> > - /* Mop up any left-over bytes. */
> > - if (offset < length)
> > + for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur
> > /= 2)
> > {
> > - src = adjust_address (src, BLKmode, offset);
> > - dest = adjust_address (dest, BLKmode, offset);
> > - move_by_pieces (dest, src, length - offset,
> > - MIN (MEM_ALIGN (src), MEM_ALIGN (dest)),
> > - (enum memop_ret) 0);
> > + mode = int_mode_for_size (delta_cur * BITS_PER_UNIT,
> > 0).require ();
> > +
> > + for (; offs + delta_cur <= length; offs += delta_cur, i++)
> > + loongarch_emit_move (adjust_address (dest, mode, offs),
> > regs[i]);
> > }
> > }
> >
> > @@ -4523,10 +4520,11 @@ loongarch_adjust_block_mem (rtx mem,
> > HOST_WIDE_INT length, rtx *loop_reg,
> >
> > static void
> > loongarch_block_move_loop (rtx dest, rtx src, HOST_WIDE_INT
> > length,
> > - HOST_WIDE_INT bytes_per_iter)
> > + HOST_WIDE_INT align)
> > {
> > rtx_code_label *label;
> > rtx src_reg, dest_reg, final_src, test;
> > + HOST_WIDE_INT bytes_per_iter = align *
> > LARCH_MAX_MOVE_OPS_PER_LOOP_ITER;
> > HOST_WIDE_INT leftover;
> >
> > leftover = length % bytes_per_iter;
> > @@ -4546,7 +4544,7 @@ loongarch_block_move_loop (rtx dest, rtx src,
> > HOST_WIDE_INT length,
> > emit_label (label);
> >
> > /* Emit the loop body. */
> > - loongarch_block_move_straight (dest, src, bytes_per_iter);
> > + loongarch_block_move_straight (dest, src, bytes_per_iter, align);
> >
> > /* Move on to the next block. */
> > loongarch_emit_move (src_reg,
> > @@ -4563,7 +4561,7 @@ loongarch_block_move_loop (rtx dest, rtx src,
> > HOST_WIDE_INT length,
> >
> > /* Mop up any left-over bytes. */
> > if (leftover)
> > - loongarch_block_move_straight (dest, src, leftover);
> > + loongarch_block_move_straight (dest, src, leftover, align);
> > else
> > /* Temporary fix for PR79150. */
> > emit_insn (gen_nop ());
> > @@ -4573,25 +4571,32 @@ loongarch_block_move_loop (rtx dest, rtx
> > src, HOST_WIDE_INT length,
> > memory reference SRC to memory reference DEST. */
> >
> > bool
> > -loongarch_expand_block_move (rtx dest, rtx src, rtx length)
> > +loongarch_expand_block_move (rtx dest, rtx src, rtx r_length, rtx
> > r_align)
> > {
> > - int max_move_bytes = LARCH_MAX_MOVE_BYTES_STRAIGHT;
> > + if (!CONST_INT_P (r_length))
> > + return false;
> > +
> > + HOST_WIDE_INT length = INTVAL (r_length);
> > + if (length > loongarch_max_inline_memcpy_size)
> > + return false;
> > +
> > + HOST_WIDE_INT align = INTVAL (r_align);
> > +
> > + if (!TARGET_STRICT_ALIGN || align > UNITS_PER_WORD)
> > + align = UNITS_PER_WORD;
> >
> > - if (CONST_INT_P (length)
> > - && INTVAL (length) <= loongarch_max_inline_memcpy_size)
> > + if (length <= align * LARCH_MAX_MOVE_OPS_STRAIGHT)
> > {
> > - if (INTVAL (length) <= max_move_bytes)
> > - {
> > - loongarch_block_move_straight (dest, src, INTVAL
> > (length));
> > - return true;
> > - }
> > - else if (optimize)
> > - {
> > - loongarch_block_move_loop (dest, src, INTVAL (length),
> > -
> > LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER);
> > - return true;
> > - }
> > + loongarch_block_move_straight (dest, src, length, align);
> > + return true;
> > + }
> > +
> > + if (optimize)
> > + {
> > + loongarch_block_move_loop (dest, src, length, align);
> > + return true;
> > }
> > +
> > return false;
> > }
> >
> > diff --git a/gcc/config/loongarch/loongarch.h
> > b/gcc/config/loongarch/loongarch.h
> > index 7151d5cabb3..1bcd144a5d9 100644
> > --- a/gcc/config/loongarch/loongarch.h
> > +++ b/gcc/config/loongarch/loongarch.h
> > @@ -1063,13 +1063,13 @@ typedef struct {
> >
> > /* The maximum number of bytes that can be copied by one iteration
> > of
> > a cpymemsi loop; see loongarch_block_move_loop. */
> > -#define LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER (UNITS_PER_WORD * 4)
> > +#define LARCH_MAX_MOVE_OPS_PER_LOOP_ITER 4
> >
> > /* The maximum number of bytes that can be copied by a straight-
> > line
> > implementation of cpymemsi; see loongarch_block_move_straight.
> > We want
> > to make sure that any loop-based implementation will iterate at
> > least twice. */
> > -#define LARCH_MAX_MOVE_BYTES_STRAIGHT
> > (LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER * 2)
> > +#define LARCH_MAX_MOVE_OPS_STRAIGHT
> > (LARCH_MAX_MOVE_OPS_PER_LOOP_ITER * 2)
> >
> > /* The base cost of a memcpy call, for MOVE_RATIO and friends.
> > These
> > values were determined experimentally by benchmarking with
> > CSiBE.
> > @@ -1077,7 +1077,7 @@ typedef struct {
> > #define LARCH_CALL_RATIO 8
> >
> > /* Any loop-based implementation of cpymemsi will have at least
> > - LARCH_MAX_MOVE_BYTES_STRAIGHT / UNITS_PER_WORD memory-to-memory
> > + LARCH_MAX_MOVE_OPS_PER_LOOP_ITER memory-to-memory
> > moves, so allow individual copies of fewer elements.
> >
> > When cpymemsi is not available, use a value approximating
> > @@ -1088,9 +1088,7 @@ typedef struct {
> > value of LARCH_CALL_RATIO to take that into account. */
> >
> > #define MOVE_RATIO(speed) \
> > - (HAVE_cpymemsi \
> > - ? LARCH_MAX_MOVE_BYTES_PER_LOOP_ITER / UNITS_PER_WORD \
> > - : CLEAR_RATIO (speed) / 2)
> > + (HAVE_cpymemsi ? LARCH_MAX_MOVE_OPS_PER_LOOP_ITER : CLEAR_RATIO
> > (speed) / 2)
> >
> > /* For CLEAR_RATIO, when optimizing for size, give a better
> > estimate
> > of the length of a memset call, but use the default otherwise.
> > */
> > diff --git a/gcc/config/loongarch/loongarch.md
> > b/gcc/config/loongarch/loongarch.md
> > index 628ecc78088..816a943d155 100644
> > --- a/gcc/config/loongarch/loongarch.md
> > +++ b/gcc/config/loongarch/loongarch.md
> > @@ -2488,7 +2488,8 @@ (define_expand "cpymemsi"
> > ""
> > {
> > if (TARGET_DO_OPTIMIZE_BLOCK_MOVE_P
> > - && loongarch_expand_block_move (operands[0], operands[1],
> > operands[2]))
> > + && loongarch_expand_block_move (operands[0], operands[1],
> > + operands[2], operands[3]))
> > DONE;
> > else
> > FAIL;
> > diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
> > b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
> > new file mode 100644
> > index 00000000000..4cd35d13904
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-1.c
> > @@ -0,0 +1,9 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mabi=lp64d -mno-strict-align" } */
> > +/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
> > +
> > +extern char a[], b[];
> > +void test() { __builtin_memcpy(a, b, 15); }
> > diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
> > b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
> > new file mode 100644
> > index 00000000000..703eb951c6d
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-2.c
> > @@ -0,0 +1,9 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
> > +/* { dg-final { scan-assembler-times "st\\.d|stptr\\.d" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.w|stptr\\.w" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.h" 1 } } */
> > +/* { dg-final { scan-assembler-times "st\\.b" 1 } } */
> > +
> > +extern long a[], b[];
> > +void test() { __builtin_memcpy(a, b, 15); }
> > diff --git a/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
> > b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
> > new file mode 100644
> > index 00000000000..d6a80659b31
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/loongarch/pr109465-3.c
> > @@ -0,0 +1,12 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mabi=lp64d -mstrict-align" } */
> > +
> > +/* Three loop iterations each contains 4 st.b, and 3 st.b after the
> > loop */
> > +/* { dg-final { scan-assembler-times "st\\.b" 7 } } */
> > +
> > +/* { dg-final { scan-assembler-not "st\\.h" } } */
> > +/* { dg-final { scan-assembler-not "st\\.w|stptr\\.w" } } */
> > +/* { dg-final { scan-assembler-not "st\\.d|stptr\\.d" } } */
> > +
> > +extern char a[], b[];
> > +void test() { __builtin_memcpy(a, b, 15); }
>
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-04-12 12:16 [GCC14 PATCH] LoongArch: Improve cpymemsi expansion [PR109465] Xi Ruoyao
2023-04-19 3:03 ` Lulu Cheng
2023-04-19 10:21 ` Pushed: " Xi Ruoyao
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