From: Juzhe-Zhong <juzhe.zhong@rivai.ai>
Date: Tue, 29 Aug 2023 10:07:38 +0000 (+0800)
Subject: RISC-V: Enable movmisalign for VLS modes
X-Git-Tag: basepoints/gcc-15~6580
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=260f743aa476abce8f88cceaca12abcb8115b02f;p=thirdparty%2Fgcc.git

RISC-V: Enable movmisalign for VLS modes

Prevous patch (which removed VLA modes movmisalign pattern) to fix run-time bug.
Such patch disable vectorization for misalign data movement.

After I check LLVM codes, LLVM supports misalign for VLS modes.

Before this patch:

sll     a5,a4,0x1
add     a5,a5,a1
lhu     a3,64(a5)
lbu     a5,66(a5)
addw    a4,a4,1
srl     a3,a3,0x8
sll     a5,a5,0x8
or      a5,a5,a3
sh      a5,0(a2)
add     a2,a2,2
bne     a4,a0,101f8 <foo+0x14>

After this patch:

foo:
	lui	a0,%hi(.LANCHOR0)
	addi	a0,a0,%lo(.LANCHOR0)
	addi	sp,sp,-16
	addi	a1,a0,1
	li	a2,64
	sd	ra,8(sp)
	vsetvli	zero,a2,e8,m4,ta,ma
	addi	a0,a0,128
	vle8.v	v4,0(a1)
	vse8.v	v4,0(a0)
	call	memcmp
	bne	a0,zero,.L6
	ld	ra,8(sp)
	addi	sp,sp,16
	jr	ra
.L6:
	call	abort

Note this patch has passed all testcases in "vect" which are related to alignment.

gcc/ChangeLog:

	* config/riscv/autovec-vls.md (movmisalign<mode>): New pattern.
	* config/riscv/riscv.cc (riscv_support_vector_misalignment): Support
	VLS misalign.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vls/misalign-1.c: New test.
---

diff --git a/gcc/config/riscv/autovec-vls.md b/gcc/config/riscv/autovec-vls.md
index 35b86de25c71..0e4701a96df4 100644
--- a/gcc/config/riscv/autovec-vls.md
+++ b/gcc/config/riscv/autovec-vls.md
@@ -144,6 +144,25 @@
   [(set_attr "type" "vmov")
    (set_attr "mode" "<MODE>")])
 
+(define_expand "movmisalign<mode>"
+  [(set (match_operand:VLS 0 "nonimmediate_operand")
+	(match_operand:VLS 1 "general_operand"))]
+  "TARGET_VECTOR"
+  {
+    /* To support misalign data movement, we should use
+       minimum element alignment load/store.  */
+    unsigned int size = GET_MODE_SIZE (GET_MODE_INNER (<MODE>mode));
+    poly_int64 nunits = GET_MODE_NUNITS (<MODE>mode) * size;
+    machine_mode mode = riscv_vector::get_vector_mode (QImode, nunits).require ();
+    operands[0] = gen_lowpart (mode, operands[0]);
+    operands[1] = gen_lowpart (mode, operands[1]);
+    if (MEM_P (operands[0]) && !register_operand (operands[1], mode))
+      operands[1] = force_reg (mode, operands[1]);
+    riscv_vector::emit_vlmax_insn (code_for_pred_mov (mode), riscv_vector::RVV_UNOP, operands);
+    DONE;
+  }
+)
+
 ;; -----------------------------------------------------------------
 ;; ---- Duplicate Operations
 ;; -----------------------------------------------------------------
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index bcc52e2627d0..2b39a6167442 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -8095,12 +8095,18 @@ riscv_support_vector_misalignment (machine_mode mode,
 				   int misalignment,
 				   bool is_packed ATTRIBUTE_UNUSED)
 {
-  /* TODO: For RVV scalable vector auto-vectorization, we should allow
-     movmisalign<mode> pattern to handle misalign data movement to unblock
-     possible auto-vectorization.
+  /* Only enable misalign data movements for VLS modes.  */
+  if (TARGET_VECTOR_VLS && STRICT_ALIGNMENT)
+    {
+      /* Return if movmisalign pattern is not supported for this mode.  */
+      if (optab_handler (movmisalign_optab, mode) == CODE_FOR_nothing)
+	return false;
 
-     RVV VLS auto-vectorization or SIMD auto-vectorization can be supported here
-     in the future.  */
+      /* Misalignment factor is unknown at compile time.  */
+      if (misalignment == -1)
+	return false;
+    }
+  /* Disable movmisalign for VLA auto-vectorization.  */
   return default_builtin_support_vector_misalignment (mode, type, misalignment,
 						      is_packed);
 }
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/misalign-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/misalign-1.c
new file mode 100644
index 000000000000..b602ffd69bbc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/misalign-1.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-schedule-insns -fno-schedule-insns2 --param=riscv-autovec-lmul=m4 -fno-tree-loop-distribute-patterns" } */
+
+#include <stdlib.h>
+
+typedef union U { unsigned short s; unsigned char c; } __attribute__((packed)) U;
+struct S { char e __attribute__((aligned (64))); U s[32]; };
+struct S t = {0, {{1}, {2}, {3}, {4}, {5}, {6}, {7}, {8},
+		  {9}, {10}, {11}, {12}, {13}, {14}, {15}, {16},
+		  {17}, {18}, {19}, {20}, {21}, {22}, {23}, {24},
+		  {25}, {26}, {27}, {28}, {29}, {30}, {31}, {32}}};
+unsigned short d[32] = { 1 };
+
+__attribute__((noinline, noclone)) void
+foo ()
+{
+  int i;
+  for (i = 0; i < 32; i++)
+    d[i] = t.s[i].s;
+  if (__builtin_memcmp (d, t.s, sizeof d))
+    abort ();
+}
+
+/* { dg-final { scan-assembler-times {vle8\.v} 1 } } */
+/* { dg-final { scan-assembler-times {vle8\.v} 1 } } */
+/* { dg-final { scan-assembler-not {vle16\.v} } } */
+/* { dg-final { scan-assembler-not {vle16\.v} } } */