| Message ID | 4fc3649e-dbfd-46eb-b9fb-1acf2a95e332.garthlei@linux.alibaba.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] RISC-V: Eliminate latter vsetvl when fused | expand |
LGTM
juzhe.zhong@rivai.ai
From: Bohan Lei
Date: 2024-09-12 12:38
To: gcc-patches
CC: juzhe.zhong
Subject: [PATCH v2] RISC-V: Eliminate latter vsetvl when fused
Resent to cc Juzhe.
------
Hi all,
A simple assembly check has been added in this version. Previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2024-September/662783.html
Thanks,
Bohan
------
The current vsetvl pass eliminates a vsetvl instruction when the previous
info is "available," but does not when "compatible." This can lead to not
only redundancy, but also incorrect behaviors when the previous info happens
to be compatible with a later vector instruction, which ends of using the
vsetvl info that should have been eliminated, as is shown in the testcase.
This patch eliminates the vsetvl when the previous info is "compatible."
gcc/ChangeLog:
* config/riscv/riscv-vsetvl.cc (pre_vsetvl::fuse_local_vsetvl_info):
Delete vsetvl insn when `prev_info` is compatible
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c: New test.
---
gcc/config/riscv/riscv-vsetvl.cc | 3 +++
.../riscv/rvv/vsetvl/vsetvl_bug-4.c | 19 +++++++++++++++++++
2 files changed, 22 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c
diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index ce831685439..030ffbe2ebb 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -2796,6 +2796,9 @@ pre_vsetvl::fuse_local_vsetvl_info ()
curr_info.dump (dump_file, " ");
}
m_dem.merge (prev_info, curr_info);
+ if (!curr_info.vl_used_by_non_rvv_insn_p ()
+ && vsetvl_insn_p (curr_info.get_insn ()->rtl ()))
+ m_delete_list.safe_push (curr_info);
if (curr_info.get_read_vl_insn ())
prev_info.set_read_vl_insn (curr_info.get_read_vl_insn ());
if (dump_file && (dump_flags & TDF_DETAILS))
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c b/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c
new file mode 100644
index 00000000000..04a8ff2945a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O2 -fno-schedule-insns -fdump-rtl-vsetvl-details" } */
+
+#include <riscv_vector.h>
+
+vuint16m1_t
+foo (vuint16m1_t a, vuint16m1_t b, size_t avl)
+{
+ size_t vl;
+ vuint16m1_t ret;
+ uint16_t c = __riscv_vmv_x_s_u16m1_u16(a);
+ vl = __riscv_vsetvl_e8mf2 (avl);
+ ret = __riscv_vadd_vx_u16m1 (a, c, avl);
+ ret = __riscv_vadd_vv_u16m1 (ret, a, vl);
+ return ret;
+}
+
+/* { dg-final { scan-rtl-dump "Eliminate insn" "vsetvl" } } */
+/* { dg-final { scan-assembler-times {vsetvli} 2 } } */
Committed.
Pan
From: 钟居哲 <juzhe.zhong@rivai.ai>
Sent: Thursday, September 12, 2024 12:40 PM
To: Bohan Lei <garthlei@linux.alibaba.com>; gcc-patches <gcc-patches@gcc.gnu.org>
Cc: Li, Pan2 <pan2.li@intel.com>
Subject: Re: [PATCH v2] RISC-V: Eliminate latter vsetvl when fused
LGTM
diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc index ce831685439..030ffbe2ebb 100644 --- a/gcc/config/riscv/riscv-vsetvl.cc +++ b/gcc/config/riscv/riscv-vsetvl.cc @@ -2796,6 +2796,9 @@ pre_vsetvl::fuse_local_vsetvl_info () curr_info.dump (dump_file, " "); } m_dem.merge (prev_info, curr_info); + if (!curr_info.vl_used_by_non_rvv_insn_p () + && vsetvl_insn_p (curr_info.get_insn ()->rtl ())) + m_delete_list.safe_push (curr_info); if (curr_info.get_read_vl_insn ()) prev_info.set_read_vl_insn (curr_info.get_read_vl_insn ()); if (dump_file && (dump_flags & TDF_DETAILS)) diff --git a/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c b/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c new file mode 100644 index 00000000000..04a8ff2945a --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/rvv/vsetvl/vsetvl_bug-4.c @@ -0,0 +1,19 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv64gcv -mabi=lp64d -O2 -fno-schedule-insns -fdump-rtl-vsetvl-details" } */ + +#include <riscv_vector.h> + +vuint16m1_t +foo (vuint16m1_t a, vuint16m1_t b, size_t avl) +{ + size_t vl; + vuint16m1_t ret; + uint16_t c = __riscv_vmv_x_s_u16m1_u16(a); + vl = __riscv_vsetvl_e8mf2 (avl); + ret = __riscv_vadd_vx_u16m1 (a, c, avl); + ret = __riscv_vadd_vv_u16m1 (ret, a, vl); + return ret; +} + +/* { dg-final { scan-rtl-dump "Eliminate insn" "vsetvl" } } */ +/* { dg-final { scan-assembler-times {vsetvli} 2 } } */