RISC-V: Rename and unify stringop strategy handling [NFC].

Hi,

now split into multiple patches.

In preparation for the vectorized strlen and strcmp support this NFC
patch unifies the stringop strategy handling a bit.  The "auto"
strategy now is a combination of scalar and vector and an expander
should try the strategies in their preferred order.

For the block_move expander this patch does just that.

Regards
 Robin

gcc/ChangeLog:

	* config/riscv/riscv-opts.h (enum riscv_stringop_strategy_enum):
	Rename...
	(enum stringop_strategy_enum): ... to this.
	* config/riscv/riscv-string.cc (riscv_expand_block_move): New
	wrapper expander handling the strategies and delegation.
	(riscv_expand_block_move_scalar): Rename function and make
	static.
	(expand_block_move): Remove strategy handling.
	* config/riscv/riscv.md: Call expander wrapper.
	* config/riscv/riscv.opt: Rename.
---
 gcc/config/riscv/riscv-opts.h                 | 18 ++--
 gcc/config/riscv/riscv-string.cc              | 92 +++++++++++--------
 gcc/config/riscv/riscv.md                     |  4 +-
 gcc/config/riscv/riscv.opt                    | 18 ++--
 .../riscv/rvv/base/cpymem-strategy-1.c        |  2 +-
 .../riscv/rvv/base/cpymem-strategy-2.c        |  2 +-
 .../riscv/rvv/base/cpymem-strategy-3.c        |  2 +-
 .../riscv/rvv/base/cpymem-strategy-4.c        |  2 +-
 .../riscv/rvv/base/cpymem-strategy-5.c        |  2 +-
 9 files changed, 78 insertions(+), 64 deletions(-)

LGTM



juzhe.zhong@rivai.ai
 
From: Robin Dapp
Date: 2023-12-01 23:21
To: gcc-patches; palmer; Kito Cheng; jeffreyalaw; juzhe.zhong@rivai.ai
CC: rdapp.gcc
Subject: [PATCH] RISC-V: Rename and unify stringop strategy handling [NFC].
Hi,
 
now split into multiple patches.
 
In preparation for the vectorized strlen and strcmp support this NFC
patch unifies the stringop strategy handling a bit.  The "auto"
strategy now is a combination of scalar and vector and an expander
should try the strategies in their preferred order.
 
For the block_move expander this patch does just that.
 
Regards
Robin
 
gcc/ChangeLog:
 
* config/riscv/riscv-opts.h (enum riscv_stringop_strategy_enum):
Rename...
(enum stringop_strategy_enum): ... to this.
* config/riscv/riscv-string.cc (riscv_expand_block_move): New
wrapper expander handling the strategies and delegation.
(riscv_expand_block_move_scalar): Rename function and make
static.
(expand_block_move): Remove strategy handling.
* config/riscv/riscv.md: Call expander wrapper.
* config/riscv/riscv.opt: Rename.
---
gcc/config/riscv/riscv-opts.h                 | 18 ++--
gcc/config/riscv/riscv-string.cc              | 92 +++++++++++--------
gcc/config/riscv/riscv.md                     |  4 +-
gcc/config/riscv/riscv.opt                    | 18 ++--
.../riscv/rvv/base/cpymem-strategy-1.c        |  2 +-
.../riscv/rvv/base/cpymem-strategy-2.c        |  2 +-
.../riscv/rvv/base/cpymem-strategy-3.c        |  2 +-
.../riscv/rvv/base/cpymem-strategy-4.c        |  2 +-
.../riscv/rvv/base/cpymem-strategy-5.c        |  2 +-
9 files changed, 78 insertions(+), 64 deletions(-)
 
diff --git a/gcc/config/riscv/riscv-opts.h b/gcc/config/riscv/riscv-opts.h
index e6e55ad7071..30efebbf07b 100644
--- a/gcc/config/riscv/riscv-opts.h
+++ b/gcc/config/riscv/riscv-opts.h
@@ -104,15 +104,15 @@ enum riscv_entity
};
/* RISC-V stringop strategy. */
-enum riscv_stringop_strategy_enum {
-  /* Use scalar or vector instructions. */
-  USE_AUTO,
-  /* Always use a library call. */
-  USE_LIBCALL,
-  /* Only use scalar instructions. */
-  USE_SCALAR,
-  /* Only use vector instructions. */
-  USE_VECTOR
+enum stringop_strategy_enum {
+  /* No expansion. */
+  STRATEGY_LIBCALL = 1,
+  /* Use scalar expansion if possible. */
+  STRATEGY_SCALAR = 2,
+  /* Only vector expansion if possible. */
+  STRATEGY_VECTOR = 4,
+  /* Use any. */
+  STRATEGY_AUTO = STRATEGY_SCALAR | STRATEGY_VECTOR
};
#define TARGET_ZICOND_LIKE (TARGET_ZICOND || (TARGET_XVENTANACONDOPS && TARGET_64BIT))
diff --git a/gcc/config/riscv/riscv-string.cc b/gcc/config/riscv/riscv-string.cc
index 80e3b5981af..f3a4d3ddd47 100644
--- a/gcc/config/riscv/riscv-string.cc
+++ b/gcc/config/riscv/riscv-string.cc
@@ -707,51 +707,68 @@ riscv_block_move_loop (rtx dest, rtx src, unsigned HOST_WIDE_INT length,
/* Expand a cpymemsi instruction, which copies LENGTH bytes from
    memory reference SRC to memory reference DEST.  */
-bool
-riscv_expand_block_move (rtx dest, rtx src, rtx length)
+static bool
+riscv_expand_block_move_scalar (rtx dest, rtx src, rtx length)
{
-  if (riscv_memcpy_strategy == USE_LIBCALL
-      || riscv_memcpy_strategy == USE_VECTOR)
+  if (!CONST_INT_P (length))
     return false;
-  if (CONST_INT_P (length))
-    {
-      unsigned HOST_WIDE_INT hwi_length = UINTVAL (length);
-      unsigned HOST_WIDE_INT factor, align;
+  unsigned HOST_WIDE_INT hwi_length = UINTVAL (length);
+  unsigned HOST_WIDE_INT factor, align;
-      align = MIN (MIN (MEM_ALIGN (src), MEM_ALIGN (dest)), BITS_PER_WORD);
-      factor = BITS_PER_WORD / align;
+  align = MIN (MIN (MEM_ALIGN (src), MEM_ALIGN (dest)), BITS_PER_WORD);
+  factor = BITS_PER_WORD / align;
-      if (optimize_function_for_size_p (cfun)
-   && hwi_length * factor * UNITS_PER_WORD > MOVE_RATIO (false))
- return false;
+  if (optimize_function_for_size_p (cfun)
+      && hwi_length * factor * UNITS_PER_WORD > MOVE_RATIO (false))
+    return false;
-      if (hwi_length <= (RISCV_MAX_MOVE_BYTES_STRAIGHT / factor))
+  if (hwi_length <= (RISCV_MAX_MOVE_BYTES_STRAIGHT / factor))
+    {
+      riscv_block_move_straight (dest, src, INTVAL (length));
+      return true;
+    }
+  else if (optimize && align >= BITS_PER_WORD)
+    {
+      unsigned min_iter_words
+ = RISCV_MAX_MOVE_BYTES_PER_LOOP_ITER / UNITS_PER_WORD;
+      unsigned iter_words = min_iter_words;
+      unsigned HOST_WIDE_INT bytes = hwi_length;
+      unsigned HOST_WIDE_INT words = bytes / UNITS_PER_WORD;
+
+      /* Lengthen the loop body if it shortens the tail.  */
+      for (unsigned i = min_iter_words; i < min_iter_words * 2 - 1; i++)
{
-   riscv_block_move_straight (dest, src, INTVAL (length));
-   return true;
+   unsigned cur_cost = iter_words + words % iter_words;
+   unsigned new_cost = i + words % i;
+   if (new_cost <= cur_cost)
+     iter_words = i;
}
-      else if (optimize && align >= BITS_PER_WORD)
- {
-   unsigned min_iter_words
-     = RISCV_MAX_MOVE_BYTES_PER_LOOP_ITER / UNITS_PER_WORD;
-   unsigned iter_words = min_iter_words;
-   unsigned HOST_WIDE_INT bytes = hwi_length;
-   unsigned HOST_WIDE_INT words = bytes / UNITS_PER_WORD;
-
-   /* Lengthen the loop body if it shortens the tail.  */
-   for (unsigned i = min_iter_words; i < min_iter_words * 2 - 1; i++)
-     {
-       unsigned cur_cost = iter_words + words % iter_words;
-       unsigned new_cost = i + words % i;
-       if (new_cost <= cur_cost)
- iter_words = i;
-     }
-   riscv_block_move_loop (dest, src, bytes, iter_words * UNITS_PER_WORD);
-   return true;
- }
+      riscv_block_move_loop (dest, src, bytes, iter_words * UNITS_PER_WORD);
+      return true;
+    }
+
+  return false;
+}
+
+/* This function delegates block-move expansion to either the vector
+   implementation or the scalar one.  Return TRUE if successful or FALSE
+   otherwise.  */
+
+bool
+riscv_expand_block_move (rtx dest, rtx src, rtx length)
+{
+  if (TARGET_VECTOR && stringop_strategy & STRATEGY_VECTOR)
+    {
+      bool ok = riscv_vector::expand_block_move (dest, src, length);
+      if (ok)
+ return true;
     }
+
+  if (stringop_strategy & STRATEGY_SCALAR)
+    return riscv_expand_block_move_scalar (dest, src, length);
+
   return false;
}
@@ -777,9 +794,8 @@ expand_block_move (rtx dst_in, rtx src_in, rtx length_in)
bnez a2, loop                   # Any more?
ret                             # Return
   */
-  if (!TARGET_VECTOR || riscv_memcpy_strategy == USE_LIBCALL
-      || riscv_memcpy_strategy == USE_SCALAR)
-    return false;
+  gcc_assert (TARGET_VECTOR);
+
   HOST_WIDE_INT potential_ew
     = (MIN (MIN (MEM_ALIGN (src_in), MEM_ALIGN (dst_in)), BITS_PER_WORD)
        / BITS_PER_UNIT);
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index 6bf2dfdf9b4..ad5f1691295 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -2336,9 +2336,7 @@ (define_expand "cpymem<mode>"
      (use (match_operand:SI 3 "const_int_operand"))])]
   ""
{
-  if (riscv_vector::expand_block_move (operands[0], operands[1], operands[2]))
-    DONE;
-  else if (riscv_expand_block_move (operands[0], operands[1], operands[2]))
+  if (riscv_expand_block_move (operands[0], operands[1], operands[2]))
     DONE;
   else
     FAIL;
diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
index 0c6517bdc8b..0e569d35760 100644
--- a/gcc/config/riscv/riscv.opt
+++ b/gcc/config/riscv/riscv.opt
@@ -536,21 +536,21 @@ Enable the use of vector registers for function arguments and return value.
This is an experimental switch and may be subject to change in the future.
Enum
-Name(riscv_stringop_strategy) Type(enum riscv_stringop_strategy_enum)
-Valid arguments to -mmemcpy-strategy=:
+Name(stringop_strategy) Type(enum stringop_strategy_enum)
+Valid arguments to -mstringop-strategy=:
EnumValue
-Enum(riscv_stringop_strategy) String(auto) Value(USE_AUTO)
+Enum(stringop_strategy) String(auto) Value(STRATEGY_AUTO)
EnumValue
-Enum(riscv_stringop_strategy) String(libcall) Value(USE_LIBCALL)
+Enum(stringop_strategy) String(libcall) Value(STRATEGY_LIBCALL)
EnumValue
-Enum(riscv_stringop_strategy) String(scalar) Value(USE_SCALAR)
+Enum(stringop_strategy) String(scalar) Value(STRATEGY_SCALAR)
EnumValue
-Enum(riscv_stringop_strategy) String(vector) Value(USE_VECTOR)
+Enum(stringop_strategy) String(vector) Value(STRATEGY_VECTOR)
-mmemcpy-strategy=
-Target RejectNegative Joined Enum(riscv_stringop_strategy) Var(riscv_memcpy_strategy) Init(USE_AUTO)
-Specify memcpy expansion strategy.
+mstringop-strategy=
+Target RejectNegative Joined Enum(stringop_strategy) Var(stringop_strategy) Init(STRATEGY_AUTO)
+Specify stringop expansion strategy.
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-1.c b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-1.c
index ae49706dca5..adad5abcef2 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-1.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-1.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-march=rv32gcv -mabi=ilp32d -mmemcpy-strategy=libcall" } */
+/* { dg-options "-march=rv32gcv -mabi=ilp32d -mstringop-strategy=libcall" } */
#include "cpymem-strategy.h"
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-2.c b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-2.c
index 73ffc5783d0..7a7c97d560c 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-2.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-2.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -march=rv32gcv -mabi=ilp32d -mmemcpy-strategy=scalar" } */
+/* { dg-options "-O2 -march=rv32gcv -mabi=ilp32d -mstringop-strategy=scalar" } */
#include "cpymem-strategy.h"
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-3.c b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-3.c
index 44f5f783962..83e5a837730 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-3.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-3.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-march=rv32gcv -mabi=ilp32d -mmemcpy-strategy=vector" } */
+/* { dg-options "-march=rv32gcv -mabi=ilp32d -mstringop-strategy=vector" } */
#include "cpymem-strategy.h"
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-4.c b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-4.c
index 8056895334a..800549c8556 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-4.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-4.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-march=rv32gcv -mabi=ilp32d -mmemcpy-strategy=auto" } */
+/* { dg-options "-march=rv32gcv -mabi=ilp32d -mstringop-strategy=auto" } */
#include "cpymem-strategy.h"
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-5.c b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-5.c
index 82ecab04a40..134fd2e9e9b 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-5.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/cpymem-strategy-5.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-march=rv32gc -mabi=ilp32d -mmemcpy-strategy=vector" } */
+/* { dg-options "-march=rv32gc -mabi=ilp32d -mstringop-strategy=vector" } */
#include "cpymem-strategy.h"