diff mbox series

[v2,2/2] MIPS: Don't expand large unaligned block move

Message ID 20230531095551.1299186-2-yunqiang.su@cipunited.com
State Accepted
Headers
Series [v2,1/2] MIPS: Use unaligned access to expand block_move on r6 |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

YunQiang Su May 31, 2023, 9:55 a.m. UTC 
  For large unaligned block move, lib call may have better performance
than expanding.

Let's just return, if length is
	larger than 64 on O32
	larger than 128 on N32/N64.

Here are some test results:

CPU		Aligned	O32	N32	N64
Cavium 7130	1	72	192	192
Cavium 7130	2	96	192	192
Cavium 7130	4	+inf	192	192
Cavium 7130	8	+inf	+inf	+inf
LS3A 2000	1	32	32	64
LS3A 2000	2	32	64	64
LS3A 2000	4	+inf	32	48
LS3A 2000	8	+inf	+inf	+inf
LS3A 4000	1	32	64	128
LS3A 4000	2	64	64	128
LS3A 4000	4	192	128	192
LS3A 4000	8	192	+inf	+inf
Ingenic X2000	1	96	-	-
Ingenic X2000	2	96	-	-
Ingenic X2000	4	+inf	-	-
interAptiv	1	64	-	-
interAptiv	2	64	-	-
interAptiv	4	+inf	-	-
P6600		1	64	128	128
P6600		2	64	128	128
P6600		4	256	192	128
P6600		8	+inf	+inf	+inf
P6600		1U	48	48	48	-mno-unaligned-access
P6600		2U	128	96	96	-mno-unaligned-access
P6600		4U	384	768	768	-mno-unaligned-access
P6600		8U	1024	+inf	+inf	-mno-unaligned-access
I6500		1	384	896	640
I6500		2	256	768	512
I6500		4	384	704	512
I6500		8	512	1024	1024
I6500		1U	32	32	32	-mno-unaligned-access
I6500		2U	96	64	64	-mno-unaligned-access
I6500		4U	384	640	768	-mno-unaligned-access
I6500		8U	256	+inf	+inf	-mno-unaligned-access

When the length of block move is larger than this value,
(g)libc call has better performance.

gcc/
	* config/mips/mips.cc (mips_expand_block_move): don't expand
	large unaligned block move.

gcc/testsuite/
	* gcc.target/mips/expand-block-move-large.c: new test.
---
 gcc/config/mips/mips.cc                       |  6 +++++
 .../gcc.target/mips/expand-block-move-large.c | 22 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/mips/expand-block-move-large.c
diff mbox series

Patch

diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc
index ca297e3c1e5..7a7f4be627f 100644
--- a/gcc/config/mips/mips.cc
+++ b/gcc/config/mips/mips.cc
@@ -8308,6 +8308,12 @@  mips_expand_block_move (rtx dest, rtx src, rtx length)
 	  || MEM_ALIGN (dest) < MIPS_MIN_MOVE_MEM_ALIGN))
     return false;
 
+  if ((ISA_HAS_LWL_LWR || ISA_HAS_UNALIGNED_ACCESS)
+      && INTVAL (length) > MIPS_MAX_MOVE_BYTES_STRAIGHT * 2
+      && MEM_ALIGN (src) < BITS_PER_WORD
+      && MEM_ALIGN (dest) < BITS_PER_WORD)
+    return false;
+
   if (INTVAL (length) <= MIPS_MAX_MOVE_BYTES_PER_LOOP_ITER)
     {
       mips_block_move_straight (dest, src, INTVAL (length));
diff --git a/gcc/testsuite/gcc.target/mips/expand-block-move-large.c b/gcc/testsuite/gcc.target/mips/expand-block-move-large.c
new file mode 100644
index 00000000000..98705f6c560
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/expand-block-move-large.c
@@ -0,0 +1,22 @@ 
+/* { dg-final { scan-assembler "memcpy" } } */
+/* { dg-final { scan-assembler-not "lwl" } } */
+/* { dg-final { scan-assembler-not "swl" } } */
+/* { dg-final { scan-assembler-not "lwr" } } */
+/* { dg-final { scan-assembler-not "swr" } } */
+/* { dg-final { scan-assembler-not "ldl" } } */
+/* { dg-final { scan-assembler-not "sdl" } } */
+/* { dg-final { scan-assembler-not "ldr" } } */
+/* { dg-final { scan-assembler-not "sdr" } } */
+
+char a[4097], b[4097];
+#ifdef __mips64
+#define MAX_SIZE 128
+#else
+#define MAX_SIZE 64
+#endif
+
+NOCOMPRESSION void
+foo ()
+{
+  __builtin_memcpy(&a[1], &b[1], MAX_SIZE + 16);
+}