[v1] RISC-V: Support FP nearbyint auto-vectorization

From: Pan Li <pan2.li@intel.com>

This patch would like to support auto-vectorization for the
nearbyint API in math.h. It depends on the -ffast-math option.

When we would like to call nearbyint/nearbyintf like v2 = nearbyint (v1),
we will convert it into below insns (reference the implementation of llvm).

* frflags a5
* vfcvt.x.f v3, v1, RDN
* vfcvt.f.x v2, v3
* fsflags a5

However, the floating point value may not need the cvt as above if
its mantissa is zero. Take single precision floating point as example:

Assume we have RTZ rounding mode

  +------------+---------------+-----------------+
  | raw float  | binary layout | after nearbyint |
  +------------+---------------+-----------------+
  | 8388607.5  | 0x4affffff    | 8388607.0       |
  | 8388608.0  | 0x4b000000    | 8388608.0       |
  | 8388609.0  | 0x4b000001    | 8388609.0       |
  +------------+---------------+-----------------+

All single floating point >= 8388608.0 will have all zero mantisaa.
We leverage vmflt and mask to filter them out in vector and only do the
cvt on mask.

Befor this patch:
math-nearbyint-1.c:21:1: missed: couldn't vectorize loop
  ...
.L3:
  flw     fa0,0(s0)
  addi    s0,s0,4
  addi    s1,s1,4
  call    nearbyint
  fsw     fa0,-4(s1)
  bne     s0,s2,.L3

After this patch:
  vfabs.v     v2,v1
  vmflt.vf    v0,v2,fa5
  frflags     a7
  vfcvt.x.f.v v4,v1,v0.t
  vfcvt.f.x.v v2,v4,v0.t
  fsflags     a7
  vfsgnj.vv   v2,v2,v1

Please note VLS mode is also involved in this patch and covered by the
test cases.

gcc/ChangeLog:

	* config/riscv/autovec.md (nearbyint<mode>2): New pattern.
	* config/riscv/riscv-protos.h (enum insn_type): New enum.
	(expand_vec_nearbyint): New function decl.
	* config/riscv/riscv-v.cc (gen_nearbyint_const_fp): New function impl.
	(expand_vec_nearbyint): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/unop/test-math.h: Add helper function.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c: New test.
	* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c: New test.

Signed-off-by: Pan Li <pan2.li@intel.com>
---
 gcc/config/riscv/autovec.md                   | 11 ++++
 gcc/config/riscv/riscv-protos.h               |  2 +
 gcc/config/riscv/riscv-v.cc                   | 36 ++++++++++++
 .../riscv/rvv/autovec/unop/math-nearbyint-0.c | 20 +++++++
 .../riscv/rvv/autovec/unop/math-nearbyint-1.c | 20 +++++++
 .../riscv/rvv/autovec/unop/math-nearbyint-2.c | 20 +++++++
 .../riscv/rvv/autovec/unop/math-nearbyint-3.c | 22 +++++++
 .../rvv/autovec/unop/math-nearbyint-run-1.c   | 48 +++++++++++++++
 .../rvv/autovec/unop/math-nearbyint-run-2.c   | 48 +++++++++++++++
 .../riscv/rvv/autovec/unop/test-math.h        | 33 +++++++++++
 .../riscv/rvv/autovec/vls/math-nearbyint-1.c  | 58 +++++++++++++++++++
 11 files changed, 318 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c

+static rtx
+gen_nearbyint_const_fp (machine_mode inner_mode)
+{
+  /* The nearbyint needs the same floating point const as ceil.  */
+  return gen_ceil_const_fp (inner_mode);
+}
This is redundant.

Also, this is also redundant:
static rtx
gen_floor_const_fp (machine_mode inner_mode)
{
  /* The floor needs the same floating point const as ceil.  */
  return gen_ceil_const_fp (inner_mode);
}

So rename it :
gen_ceil_const_fp (machine_mode inner_mode)

into:
get_fp_rounding_coefficient



juzhe.zhong@rivai.ai
 
From: pan2.li
Date: 2023-09-26 10:39
To: gcc-patches
CC: juzhe.zhong; pan2.li; yanzhang.wang; kito.cheng
Subject: [PATCH v1] RISC-V: Support FP nearbyint auto-vectorization
From: Pan Li <pan2.li@intel.com>
 
This patch would like to support auto-vectorization for the
nearbyint API in math.h. It depends on the -ffast-math option.
 
When we would like to call nearbyint/nearbyintf like v2 = nearbyint (v1),
we will convert it into below insns (reference the implementation of llvm).
 
* frflags a5
* vfcvt.x.f v3, v1, RDN
* vfcvt.f.x v2, v3
* fsflags a5
 
However, the floating point value may not need the cvt as above if
its mantissa is zero. Take single precision floating point as example:
 
Assume we have RTZ rounding mode
 
  +------------+---------------+-----------------+
  | raw float  | binary layout | after nearbyint |
  +------------+---------------+-----------------+
  | 8388607.5  | 0x4affffff    | 8388607.0       |
  | 8388608.0  | 0x4b000000    | 8388608.0       |
  | 8388609.0  | 0x4b000001    | 8388609.0       |
  +------------+---------------+-----------------+
 
All single floating point >= 8388608.0 will have all zero mantisaa.
We leverage vmflt and mask to filter them out in vector and only do the
cvt on mask.
 
Befor this patch:
math-nearbyint-1.c:21:1: missed: couldn't vectorize loop
  ...
.L3:
  flw     fa0,0(s0)
  addi    s0,s0,4
  addi    s1,s1,4
  call    nearbyint
  fsw     fa0,-4(s1)
  bne     s0,s2,.L3
 
After this patch:
  vfabs.v     v2,v1
  vmflt.vf    v0,v2,fa5
  frflags     a7
  vfcvt.x.f.v v4,v1,v0.t
  vfcvt.f.x.v v2,v4,v0.t
  fsflags     a7
  vfsgnj.vv   v2,v2,v1
 
Please note VLS mode is also involved in this patch and covered by the
test cases.
 
gcc/ChangeLog:
 
* config/riscv/autovec.md (nearbyint<mode>2): New pattern.
* config/riscv/riscv-protos.h (enum insn_type): New enum.
(expand_vec_nearbyint): New function decl.
* config/riscv/riscv-v.cc (gen_nearbyint_const_fp): New function impl.
(expand_vec_nearbyint): Ditto.
 
gcc/testsuite/ChangeLog:
 
* gcc.target/riscv/rvv/autovec/unop/test-math.h: Add helper function.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c: New test.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c: New test.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c: New test.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c: New test.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c: New test.
* gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c: New test.
* gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c: New test.
 
Signed-off-by: Pan Li <pan2.li@intel.com>
---
gcc/config/riscv/autovec.md                   | 11 ++++
gcc/config/riscv/riscv-protos.h               |  2 +
gcc/config/riscv/riscv-v.cc                   | 36 ++++++++++++
.../riscv/rvv/autovec/unop/math-nearbyint-0.c | 20 +++++++
.../riscv/rvv/autovec/unop/math-nearbyint-1.c | 20 +++++++
.../riscv/rvv/autovec/unop/math-nearbyint-2.c | 20 +++++++
.../riscv/rvv/autovec/unop/math-nearbyint-3.c | 22 +++++++
.../rvv/autovec/unop/math-nearbyint-run-1.c   | 48 +++++++++++++++
.../rvv/autovec/unop/math-nearbyint-run-2.c   | 48 +++++++++++++++
.../riscv/rvv/autovec/unop/test-math.h        | 33 +++++++++++
.../riscv/rvv/autovec/vls/math-nearbyint-1.c  | 58 +++++++++++++++++++
11 files changed, 318 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c
 
diff --git a/gcc/config/riscv/autovec.md b/gcc/config/riscv/autovec.md
index a005e17457e..b47f086f5e6 100644
--- a/gcc/config/riscv/autovec.md
+++ b/gcc/config/riscv/autovec.md
@@ -2210,6 +2210,7 @@ (define_expand "<u>avg<v_double_trunc>3_ceil"
;; Includes:
;; - ceil/ceilf
;; - floor/floorf
+;; - nearbyint/nearbyintf
;; -------------------------------------------------------------------------
(define_expand "ceil<mode>2"
   [(match_operand:V_VLSF 0 "register_operand")
@@ -2230,3 +2231,13 @@ (define_expand "floor<mode>2"
     DONE;
   }
)
+
+(define_expand "nearbyint<mode>2"
+  [(match_operand:V_VLSF 0 "register_operand")
+   (match_operand:V_VLSF 1 "register_operand")]
+  "TARGET_VECTOR && !flag_trapping_math && !flag_rounding_math"
+  {
+    riscv_vector::expand_vec_nearbyint (operands[0], operands[1], <MODE>mode, <VCONVERT>mode);
+    DONE;
+  }
+)
diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
index 63eb2475705..f87bdef0f71 100644
--- a/gcc/config/riscv/riscv-protos.h
+++ b/gcc/config/riscv/riscv-protos.h
@@ -296,6 +296,7 @@ enum insn_type : unsigned int
   UNARY_OP_TAMA = __MASK_OP_TAMA | UNARY_OP_P,
   UNARY_OP_TAMU = __MASK_OP_TAMU | UNARY_OP_P,
   UNARY_OP_FRM_DYN = UNARY_OP | FRM_DYN_P,
+  UNARY_OP_TAMU_FRM_DYN = UNARY_OP_TAMU | FRM_DYN_P,
   UNARY_OP_TAMU_FRM_RUP = UNARY_OP_TAMU | FRM_RUP_P,
   UNARY_OP_TAMU_FRM_RDN = UNARY_OP_TAMU | FRM_RDN_P,
@@ -460,6 +461,7 @@ void expand_cond_len_binop (unsigned, rtx *);
void expand_reduction (unsigned, unsigned, rtx *, rtx);
void expand_vec_ceil (rtx, rtx, machine_mode, machine_mode);
void expand_vec_floor (rtx, rtx, machine_mode, machine_mode);
+void expand_vec_nearbyint (rtx, rtx, machine_mode, machine_mode);
#endif
bool sew64_scalar_helper (rtx *, rtx *, rtx, machine_mode,
  bool, void (*)(rtx *, rtx));
diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index a1ffefb23f3..4749dadf2d4 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -3571,6 +3571,13 @@ gen_floor_const_fp (machine_mode inner_mode)
   return gen_ceil_const_fp (inner_mode);
}
+static rtx
+gen_nearbyint_const_fp (machine_mode inner_mode)
+{
+  /* The nearbyint needs the same floating point const as ceil.  */
+  return gen_ceil_const_fp (inner_mode);
+}
+
static rtx
emit_vec_float_cmp_mask (rtx fp_vector, rtx_code code, rtx fp_scalar,
machine_mode vec_fp_mode)
@@ -3676,4 +3683,33 @@ expand_vec_floor (rtx op_0, rtx op_1, machine_mode vec_fp_mode,
   emit_vec_copysign (op_0, op_0, op_1, vec_fp_mode);
}
+void
+expand_vec_nearbyint (rtx op_0, rtx op_1, machine_mode vec_fp_mode,
+       machine_mode vec_int_mode)
+{
+  /* Step-1: Get the abs float value for mask generation.  */
+  emit_vec_abs (op_0, op_1, vec_fp_mode);
+
+  /* Step-2: Generate the mask on const fp.  */
+  rtx const_fp = gen_nearbyint_const_fp (GET_MODE_INNER (vec_fp_mode));
+  rtx mask = emit_vec_float_cmp_mask (op_0, LT, const_fp, vec_fp_mode);
+
+  /* Step-3: Backup FP exception flags, nearbyint never raise exceptions. */
+  rtx fflags = gen_reg_rtx (SImode);
+  emit_insn (gen_riscv_frflags (fflags));
+
+  /* Step-4: Convert to integer on mask, with rounding down (aka nearbyint).  */
+  rtx tmp = gen_reg_rtx (vec_int_mode);
+  emit_vec_cvt_x_f (tmp, op_1, mask, UNARY_OP_TAMU_FRM_DYN, vec_fp_mode);
+
+  /* Step-5: Convert to floating-point on mask for the nearbyint result.  */
+  emit_vec_cvt_f_x (op_0, tmp, mask, UNARY_OP_TAMU_FRM_DYN, vec_fp_mode);
+
+  /* Step-6: Restore FP exception flags. */
+  emit_insn (gen_riscv_fsflags (fflags));
+
+  /* Step-7: Retrieve the sign bit for -0.0.  */
+  emit_vec_copysign (op_0, op_0, op_1, vec_fp_mode);
+}
+
} // namespace riscv_vector
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c
new file mode 100644
index 00000000000..f67b22ac02d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-0.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv_zvfh -mabi=lp64d -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math -fno-schedule-insns -fno-schedule-insns2" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "test-math.h"
+
+/*
+** test__Float16___builtin_nearbyintf16:
+**   ...
+**   vsetvli\s+[atx][0-9]+,\s*zero,\s*e16,\s*m1,\s*ta,\s*mu
+**   vfabs\.v\s+v[0-9]+,\s*v[0-9]+
+**   vmflt\.vf\s+v0,\s*v[0-9]+,\s*[fa]+[0-9]+
+**   frflags\s+[axt][0-9]+
+**   vfcvt\.x\.f\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   vfcvt\.f\.x\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   fsflags\s+[axt][0-9]+
+**   vfsgnj\.vv\s+v[0-9]+,v[0-9]+,v[0-9]+
+**   ...
+*/
+TEST_UNARY_CALL (_Float16, __builtin_nearbyintf16)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c
new file mode 100644
index 00000000000..93639863412
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-1.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math -fno-schedule-insns -fno-schedule-insns2" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "test-math.h"
+
+/*
+** test_float___builtin_nearbyintf:
+**   ...
+**   vsetvli\s+[atx][0-9]+,\s*zero,\s*e32,\s*m1,\s*ta,\s*mu
+**   vfabs\.v\s+v[0-9]+,\s*v[0-9]+
+**   vmflt\.vf\s+v0,\s*v[0-9]+,\s*[fa]+[0-9]+
+**   frflags\s+[axt][0-9]+
+**   vfcvt\.x\.f\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   vfcvt\.f\.x\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   fsflags\s+[axt][0-9]+
+**   vfsgnj\.vv\s+v[0-9]+,v[0-9]+,v[0-9]+
+**   ...
+*/
+TEST_UNARY_CALL (float, __builtin_nearbyintf)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c
new file mode 100644
index 00000000000..d31de739d2d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-2.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math -fno-schedule-insns -fno-schedule-insns2" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "test-math.h"
+
+/*
+** test_double___builtin_nearbyint:
+**   ...
+**   vsetvli\s+[atx][0-9]+,\s*zero,\s*e64,\s*m1,\s*ta,\s*mu
+**   vfabs\.v\s+v[0-9]+,\s*v[0-9]+
+**   vmflt\.vf\s+v0,\s*v[0-9]+,\s*[fa]+[0-9]+
+**   frflags\s+[axt][0-9]+
+**   vfcvt\.x\.f\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   vfcvt\.f\.x\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   fsflags\s+[axt][0-9]+
+**   vfsgnj\.vv\s+v[0-9]+,v[0-9]+,v[0-9]+
+**   ...
+*/
+TEST_UNARY_CALL (double, __builtin_nearbyint)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c
new file mode 100644
index 00000000000..4fd99505b40
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-3.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math -fno-schedule-insns -fno-schedule-insns2" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "test-math.h"
+
+/*
+** test_float___builtin_nearbyintf:
+**   ...
+**   vsetvli\s+[atx][0-9]+,\s*zero,\s*e32,\s*m1,\s*ta,\s*mu
+**   vfabs\.v\s+v[0-9]+,\s*v[0-9]+
+**   vmflt\.vf\s+v0,\s*v[0-9]+,\s*[fa]+[0-9]+
+**   frflags\s+[axt][0-9]+
+**   vfcvt\.x\.f\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   vfcvt\.f\.x\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t
+**   fsflags\s+[axt][0-9]+
+**   vfsgnj\.vv\s+v[0-9]+,v[0-9]+,v[0-9]+
+**   ...
+**   vmerge\.vvm\s+v[0-9]+,\s*v[0-9]+,\s*v[0-9]+,\s*v0
+**   ...
+*/
+TEST_COND_UNARY_CALL (float, __builtin_nearbyintf)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c
new file mode 100644
index 00000000000..7f49485822a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-1.c
@@ -0,0 +1,48 @@
+/* { dg-do run { target { riscv_vector } } } */
+/* { dg-additional-options "-std=c99 -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math" } */
+
+#include "test-math.h"
+
+#define ARRAY_SIZE 128
+
+float in[ARRAY_SIZE];
+float out[ARRAY_SIZE];
+float ref[ARRAY_SIZE];
+
+TEST_UNARY_CALL (float, __builtin_nearbyintf)
+TEST_ASSERT (float)
+
+TEST_INIT (float, 1.2, 1.0, 1)
+TEST_INIT (float, -1.2, -1.0, 2)
+TEST_INIT (float, 3.0, 3.0, 3)
+TEST_INIT (float, 8388607.5, 8388607.0, 4)
+TEST_INIT (float, 8388609.0, 8388609.0, 5)
+TEST_INIT (float, 0.0, 0.0, 6)
+TEST_INIT (float, -0.0, -0.0, 7)
+TEST_INIT (float, -8388607.5, -8388607.0, 8)
+TEST_INIT (float, -8388608.0, -8388608.0, 9)
+
+int
+main ()
+{
+  unsigned fflags_before = get_fflags ();
+
+  set_rm (FRM_RTZ);
+
+  RUN_TEST (float, 1, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 2, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 3, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 4, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 5, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 6, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 7, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 8, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (float, 9, __builtin_nearbyintf, in, out, ref, ARRAY_SIZE);
+
+  unsigned fflags_after = get_fflags ();
+
+  if (fflags_before != fflags_after)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c
new file mode 100644
index 00000000000..4f8c7246b5e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/math-nearbyint-run-2.c
@@ -0,0 +1,48 @@
+/* { dg-do run { target { riscv_vector } } } */
+/* { dg-additional-options "-std=c99 -O3 -ftree-vectorize -fno-vect-cost-model -ffast-math" } */
+
+#include "test-math.h"
+
+#define ARRAY_SIZE 128
+
+double in[ARRAY_SIZE];
+double out[ARRAY_SIZE];
+double ref[ARRAY_SIZE];
+
+TEST_UNARY_CALL (double, __builtin_nearbyint)
+TEST_ASSERT (double)
+
+TEST_INIT (double, 1.2, 1.0, 1)
+TEST_INIT (double, -1.8, -2.0, 2)
+TEST_INIT (double, 3.0, 3.0, 3)
+TEST_INIT (double, 4503599627370495.5, 4503599627370496.0, 4)
+TEST_INIT (double, 4503599627370497.0, 4503599627370497.0, 5)
+TEST_INIT (double, 0.0, 0.0, 6)
+TEST_INIT (double, -0.0, -0.0, 7)
+TEST_INIT (double, -4503599627370495.5, -4503599627370496.0, 8)
+TEST_INIT (double, -4503599627370496.0, -4503599627370496.0, 9)
+
+int
+main ()
+{
+  unsigned fflags_before = get_fflags ();
+
+  set_rm (FRM_RNE);
+
+  RUN_TEST (double, 1, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 2, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 3, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 4, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 5, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 6, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 7, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 8, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+  RUN_TEST (double, 9, __builtin_nearbyint, in, out, ref, ARRAY_SIZE);
+
+  unsigned fflags_after = get_fflags ();
+
+  if (fflags_before != fflags_after)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/test-math.h b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/test-math.h
index d035835f370..b63ca56d848 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/test-math.h
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/unop/test-math.h
@@ -36,3 +36,36 @@
   test_##TYPE##_init_##NUM (IN, REF, SIZE);           \
   test_##TYPE##_##CALL (OUT, IN, SIZE);               \
   test_##TYPE##_assert (OUT, REF, SIZE);
+
+#define FRM_RNE 0
+#define FRM_RTZ 1
+#define FRM_RDN 2
+#define FRM_RUP 3
+#define FRM_RMM 4
+#define FRM_DYN 7
+
+static inline void
+set_rm (unsigned rm)
+{
+  __asm__ volatile (
+    "fsrm %0"
+    :
+    :"r"(rm)
+    :
+  );
+}
+
+static inline unsigned
+get_fflags ()
+{
+  unsigned fflags = 0;
+
+  __asm__ volatile (
+    "frflags %0"
+    :"=r"(fflags)
+    :
+    :
+  );
+
+  return fflags;
+}
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c
new file mode 100644
index 00000000000..8c8498c5982
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/math-nearbyint-1.c
@@ -0,0 +1,58 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv_zvfh_zvl4096b -mabi=lp64d -O3 --param=riscv-autovec-lmul=m8 -ffast-math -fdump-tree-optimized" } */
+
+#include "def.h"
+
+DEF_OP_V (nearbyintf16, 1, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 2, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 4, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 8, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 16, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 32, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 64, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 128, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 256, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 512, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 1024, _Float16, __builtin_nearbyintf16)
+DEF_OP_V (nearbyintf16, 2048, _Float16, __builtin_nearbyintf16)
+
+DEF_OP_V (nearbyintf, 1, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 2, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 4, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 8, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 16, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 32, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 64, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 128, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 256, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 512, float, __builtin_nearbyintf)
+DEF_OP_V (nearbyintf, 1024, float, __builtin_nearbyintf)
+
+DEF_OP_V (nearbyint, 1, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 2, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 4, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 8, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 16, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 32, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 64, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 128, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 256, double, __builtin_nearbyint)
+DEF_OP_V (nearbyint, 512, double, __builtin_nearbyint)
+
+/* { dg-final { scan-assembler-not {csrr} } } */
+/* { dg-final { scan-tree-dump-not "1,1" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "2,2" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "4,4" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "16,16" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "32,32" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "64,64" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "128,128" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "256,256" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "512,512" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "1024,1024" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "2048,2048" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "4096,4096" "optimized" } } */
+/* { dg-final { scan-assembler-times {vfcvt\.x\.f\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t} 30 } } */
+/* { dg-final { scan-assembler-times {vfcvt\.f\.x\.v\s+v[0-9]+,\s*v[0-9]+,\s*v0\.t} 30 } } */
+/* { dg-final { scan-assembler-times {frflags\s+[atx][0-9]+} 30 } } */
+/* { dg-final { scan-assembler-times {fsflags\s+[atx][0-9]+} 30 } } */

Sure thing, will send another patch for the renaming first.

Pan

From: juzhe.zhong@rivai.ai <juzhe.zhong@rivai.ai>
Sent: Tuesday, September 26, 2023 10:59 AM
To: Li, Pan2 <pan2.li@intel.com>; gcc-patches <gcc-patches@gcc.gnu.org>
Cc: Li, Pan2 <pan2.li@intel.com>; Wang, Yanzhang <yanzhang.wang@intel.com>; kito.cheng <kito.cheng@gmail.com>
Subject: Re: [PATCH v1] RISC-V: Support FP nearbyint auto-vectorization


+static rtx

+gen_nearbyint_const_fp (machine_mode inner_mode)

+{

+  /* The nearbyint needs the same floating point const as ceil.  */

+  return gen_ceil_const_fp (inner_mode);

+}
This is redundant.

Also, this is also redundant:
static rtx
gen_floor_const_fp (machine_mode inner_mode)
{
  /* The floor needs the same floating point const as ceil.  */
  return gen_ceil_const_fp (inner_mode);
}

So rename it :
gen_ceil_const_fp (machine_mode inner_mode)

into:
get_fp_rounding_coefficient