https://gcc.gnu.org/g:db2ad3d782827fefec35b3cf140a3690033098af
commit db2ad3d782827fefec35b3cf140a3690033098af
Author: Christoph Müllner <christoph.muell...@vrull.eu>
Date: Mon Apr 29 02:53:20 2024 +0200
RISC-V: Allow by-pieces to do overlapping accesses in block_move_straight
The current implementation of riscv_block_move_straight() emits a couple
of loads/stores with with maximum width (e.g. 8-byte for RV64).
The remainder is handed over to move_by_pieces().
The by-pieces framework utilizes target hooks to decide about the emitted
instructions (e.g. unaligned accesses or overlapping accesses).
Since the current implementation will always request less than XLEN bytes
to be handled by the by-pieces infrastructure, it is impossible that
overlapping memory accesses can ever be emitted (the by-pieces code does
not know of any previous instructions that were emitted by the backend).
This patch changes the implementation of riscv_block_move_straight()
such, that it utilizes the by-pieces framework if the remaining data
is less than 2*XLEN bytes, which is sufficient to enable overlapping
memory accesses (if the requirements for them are given).
The changes in the expansion can be seen in the adjustments of the
cpymem-NN-ooo test cases. The changes in the cpymem-NN tests are
caused by the different instruction ordering of the code emitted
by the by-pieces infrastructure, which emits alternating load/store
sequences.
gcc/ChangeLog:
* config/riscv/riscv-string.cc (riscv_block_move_straight):
Hand over up to 2xXLEN bytes to move_by_pieces().
gcc/testsuite/ChangeLog:
* gcc.target/riscv/cpymem-32-ooo.c: Adjustments for overlapping
access.
* gcc.target/riscv/cpymem-32.c: Adjustments for code emitted by
by-pieces.
* gcc.target/riscv/cpymem-64-ooo.c: Adjustments for overlapping
access.
* gcc.target/riscv/cpymem-64.c: Adjustments for code emitted by
by-pieces.
Signed-off-by: Christoph Müllner <christoph.muell...@vrull.eu>
(cherry picked from commit ad22c607f3e17f2c6ca45699c1d88adaa618c23c)
Diff:
---
gcc/config/riscv/riscv-string.cc | 6 +++---
gcc/testsuite/gcc.target/riscv/cpymem-32-ooo.c | 16 ++++++++--------
gcc/testsuite/gcc.target/riscv/cpymem-32.c | 10 ++++------
gcc/testsuite/gcc.target/riscv/cpymem-64-ooo.c | 8 ++++----
gcc/testsuite/gcc.target/riscv/cpymem-64.c | 9 +++------
5 files changed, 22 insertions(+), 27 deletions(-)
diff --git a/gcc/config/riscv/riscv-string.cc b/gcc/config/riscv/riscv-string.cc
index b6cd7032356..96394844bbb 100644
--- a/gcc/config/riscv/riscv-string.cc
+++ b/gcc/config/riscv/riscv-string.cc
@@ -637,18 +637,18 @@ riscv_block_move_straight (rtx dest, rtx src, unsigned
HOST_WIDE_INT length,
delta = bits / BITS_PER_UNIT;
/* Allocate a buffer for the temporary registers. */
- regs = XALLOCAVEC (rtx, length / delta);
+ regs = XALLOCAVEC (rtx, length / delta - 1);
/* 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 (offset = 0, i = 0; offset + 2 * delta <= length; offset += delta, i++)
{
regs[i] = gen_reg_rtx (mode);
riscv_emit_move (regs[i], adjust_address (src, mode, offset));
}
/* Copy the chunks to the destination. */
- for (offset = 0, i = 0; offset + delta <= length; offset += delta, i++)
+ for (offset = 0, i = 0; offset + 2 * delta <= length; offset += delta, i++)
riscv_emit_move (adjust_address (dest, mode, offset), regs[i]);
/* Mop up any left-over bytes. */
diff --git a/gcc/testsuite/gcc.target/riscv/cpymem-32-ooo.c
b/gcc/testsuite/gcc.target/riscv/cpymem-32-ooo.c
index 947d58c30fa..2a48567353a 100644
--- a/gcc/testsuite/gcc.target/riscv/cpymem-32-ooo.c
+++ b/gcc/testsuite/gcc.target/riscv/cpymem-32-ooo.c
@@ -91,8 +91,8 @@ COPY_ALIGNED_N(11)
** ...
** sw\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],14\([at][0-9]\)
-** sb\t[at][0-9],14\([at][0-9]\)
+** lw\t[at][0-9],11\([at][0-9]\)
+** sw\t[at][0-9],11\([at][0-9]\)
** ...
*/
COPY_N(15)
@@ -104,8 +104,8 @@ COPY_N(15)
** ...
** sw\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],14\([at][0-9]\)
-** sb\t[at][0-9],14\([at][0-9]\)
+** lw\t[at][0-9],11\([at][0-9]\)
+** sw\t[at][0-9],11\([at][0-9]\)
** ...
*/
COPY_ALIGNED_N(15)
@@ -117,8 +117,8 @@ COPY_ALIGNED_N(15)
** ...
** sw\t[at][0-9],20\([at][0-9]\)
** ...
-** lbu\t[at][0-9],26\([at][0-9]\)
-** sb\t[at][0-9],26\([at][0-9]\)
+** lw\t[at][0-9],23\([at][0-9]\)
+** sw\t[at][0-9],23\([at][0-9]\)
** ...
*/
COPY_N(27)
@@ -130,8 +130,8 @@ COPY_N(27)
** ...
** sw\t[at][0-9],20\([at][0-9]\)
** ...
-** lbu\t[at][0-9],26\([at][0-9]\)
-** sb\t[at][0-9],26\([at][0-9]\)
+** lw\t[at][0-9],23\([at][0-9]\)
+** sw\t[at][0-9],23\([at][0-9]\)
** ...
*/
COPY_ALIGNED_N(27)
diff --git a/gcc/testsuite/gcc.target/riscv/cpymem-32.c
b/gcc/testsuite/gcc.target/riscv/cpymem-32.c
index 44ba14a1d51..2030a39ca97 100644
--- a/gcc/testsuite/gcc.target/riscv/cpymem-32.c
+++ b/gcc/testsuite/gcc.target/riscv/cpymem-32.c
@@ -24,10 +24,10 @@ void copy_aligned_##N (void *to, void *from)
\
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],6\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],6\([at][0-9]\)
+** ...
** sb\t[at][0-9],6\([at][0-9]\)
** ...
*/
@@ -50,10 +50,9 @@ COPY_ALIGNED_N(7)
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],7\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],7\([at][0-9]\)
** sb\t[at][0-9],7\([at][0-9]\)
** ...
*/
@@ -73,10 +72,9 @@ COPY_ALIGNED_N(8)
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],10\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],10\([at][0-9]\)
** sb\t[at][0-9],10\([at][0-9]\)
** ...
*/
diff --git a/gcc/testsuite/gcc.target/riscv/cpymem-64-ooo.c
b/gcc/testsuite/gcc.target/riscv/cpymem-64-ooo.c
index 108748690cd..147324093cb 100644
--- a/gcc/testsuite/gcc.target/riscv/cpymem-64-ooo.c
+++ b/gcc/testsuite/gcc.target/riscv/cpymem-64-ooo.c
@@ -110,8 +110,8 @@ COPY_ALIGNED_N(15)
** ...
** sd\t[at][0-9],16\([at][0-9]\)
** ...
-** lbu\t[at][0-9],26\([at][0-9]\)
-** sb\t[at][0-9],26\([at][0-9]\)
+** lw\t[at][0-9],23\([at][0-9]\)
+** sw\t[at][0-9],23\([at][0-9]\)
** ...
*/
COPY_N(27)
@@ -123,8 +123,8 @@ COPY_N(27)
** ...
** sd\t[at][0-9],16\([at][0-9]\)
** ...
-** lbu\t[at][0-9],26\([at][0-9]\)
-** sb\t[at][0-9],26\([at][0-9]\)
+** lw\t[at][0-9],23\([at][0-9]\)
+** sw\t[at][0-9],23\([at][0-9]\)
** ...
*/
COPY_ALIGNED_N(27)
diff --git a/gcc/testsuite/gcc.target/riscv/cpymem-64.c
b/gcc/testsuite/gcc.target/riscv/cpymem-64.c
index bdfaca0d46a..37b8ef0e020 100644
--- a/gcc/testsuite/gcc.target/riscv/cpymem-64.c
+++ b/gcc/testsuite/gcc.target/riscv/cpymem-64.c
@@ -24,10 +24,9 @@ void copy_aligned_##N (void *to, void *from) \
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],6\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],6\([at][0-9]\)
** sb\t[at][0-9],6\([at][0-9]\)
** ...
*/
@@ -50,10 +49,9 @@ COPY_ALIGNED_N(7)
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],7\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],7\([at][0-9]\)
** sb\t[at][0-9],7\([at][0-9]\)
** ...
*/
@@ -73,10 +71,9 @@ COPY_ALIGNED_N(8)
** ...
** lbu\t[at][0-9],0\([at][0-9]\)
** ...
-** lbu\t[at][0-9],10\([at][0-9]\)
-** ...
** sb\t[at][0-9],0\([at][0-9]\)
** ...
+** lbu\t[at][0-9],10\([at][0-9]\)
** sb\t[at][0-9],10\([at][0-9]\)
** ...
*/
