[gcc r14-4077] RISC-V: Expand VLS mode to scalar mode move[PR111391]

[gcc r14-4077] RISC-V: Expand VLS mode to scalar mode move[PR111391]

[Pan Li]

https://gcc.gnu.org/g:86451305d8b2a25e7c6ea6c2f1ee69c419cba3ef

commit r14-4077-g86451305d8b2a25e7c6ea6c2f1ee69c419cba3ef
Author: Juzhe-Zhong <juzhe.zhong@rivai.ai>
Date:   Thu Sep 14 18:49:52 2023 +0800

    RISC-V: Expand VLS mode to scalar mode move[PR111391]
    
    This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111391
    
            PR target/111391
    
    gcc/ChangeLog:
    
            * config/riscv/autovec.md (@vec_extract<mode><vel>): Remove @.
            (vec_extract<mode><vel>): Ditto.
            * config/riscv/riscv-vsetvl.cc (emit_vsetvl_insn): Fix bug.
            (pass_vsetvl::local_eliminate_vsetvl_insn): Fix bug.
            * config/riscv/riscv.cc (riscv_legitimize_move): Expand VLS mode to scalar mode move.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/riscv/rvv/autovec/partial/slp-9.c: Adapt test.
            * gcc.target/riscv/rvv/autovec/pr111391-1.c: New test.
            * gcc.target/riscv/rvv/autovec/pr111391-2.c: New test.

Diff:
---
 gcc/config/riscv/autovec.md                        |  2 +-
 gcc/config/riscv/riscv-vsetvl.cc                   |  4 +-
 gcc/config/riscv/riscv.cc                          | 64 ++++++++++++++++++++++
 .../gcc.target/riscv/rvv/autovec/partial/slp-9.c   |  1 -
 .../gcc.target/riscv/rvv/autovec/pr111391-1.c      | 28 ++++++++++
 .../gcc.target/riscv/rvv/autovec/pr111391-2.c      | 10 ++++
 6 files changed, 106 insertions(+), 3 deletions(-)

diff --git a/gcc/config/riscv/autovec.md b/gcc/config/riscv/autovec.md
index c6175a3b1f6..aca86554a94 100644
--- a/gcc/config/riscv/autovec.md
+++ b/gcc/config/riscv/autovec.md
@@ -1442,7 +1442,7 @@
 ;; -------------------------------------------------------------------------
 ;; ---- [INT,FP] Extract a vector element.
 ;; -------------------------------------------------------------------------
-(define_expand "@vec_extract<mode><vel>"
+(define_expand "vec_extract<mode><vel>"
   [(set (match_operand:<VEL>	  0 "register_operand")
      (vec_select:<VEL>
        (match_operand:V_VLS	  1 "register_operand")
diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index dc02246756d..5f031c18df5 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -649,6 +649,8 @@ emit_vsetvl_insn (enum vsetvl_type insn_type, enum emit_type emit_type,
     {
       fprintf (dump_file, "\nInsert vsetvl insn PATTERN:\n");
       print_rtl_single (dump_file, pat);
+      fprintf (dump_file, "\nfor insn:\n");
+      print_rtl_single (dump_file, rinsn);
     }
 
   if (emit_type == EMIT_DIRECT)
@@ -3867,7 +3869,7 @@ pass_vsetvl::local_eliminate_vsetvl_insn (const bb_info *bb) const
 	      skip_one = true;
 	    }
 
-	  curr_avl = get_avl (rinsn);
+	  curr_avl = curr_dem.get_avl ();
 
 	  /* Some instrucion like pred_extract_first<mode> don't reqruie avl, so
 	     the avl is null, use vl_placeholder for unify the handling
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 762937b0e37..8c766e2e2be 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -2513,6 +2513,70 @@ riscv_legitimize_move (machine_mode mode, rtx dest, rtx src)
 	}
       return true;
     }
+  /* Expand
+       (set (reg:DI target) (subreg:DI (reg:V8QI reg) 0))
+     Expand this data movement instead of simply forbid it since
+     we can improve the code generation for this following scenario
+     by RVV auto-vectorization:
+       (set (reg:V8QI 149) (vec_duplicate:V8QI (reg:QI))
+       (set (reg:DI target) (subreg:DI (reg:V8QI reg) 0))
+     Since RVV mode and scalar mode are in different REG_CLASS,
+     we need to explicitly move data from V_REGS to GR_REGS by scalar move.  */
+  if (SUBREG_P (src) && riscv_v_ext_mode_p (GET_MODE (SUBREG_REG (src))))
+    {
+      machine_mode vmode = GET_MODE (SUBREG_REG (src));
+      unsigned int mode_size = GET_MODE_SIZE (mode).to_constant ();
+      unsigned int vmode_size = GET_MODE_SIZE (vmode).to_constant ();
+      unsigned int nunits = vmode_size / mode_size;
+      scalar_mode smode = as_a<scalar_mode> (mode);
+      unsigned int index = SUBREG_BYTE (src).to_constant () / mode_size;
+      unsigned int num = smode == DImode && !TARGET_VECTOR_ELEN_64 ? 2 : 1;
+
+      if (num == 2)
+	{
+	  /* If we want to extract 64bit value but ELEN < 64,
+	     we use RVV vector mode with EEW = 32 to extract
+	     the highpart and lowpart.  */
+	  smode = SImode;
+	  nunits = nunits * 2;
+	}
+      vmode = riscv_vector::get_vector_mode (smode, nunits).require ();
+      enum insn_code icode
+	= convert_optab_handler (vec_extract_optab, vmode, smode);
+      gcc_assert (icode != CODE_FOR_nothing);
+      rtx v = gen_lowpart (vmode, SUBREG_REG (src));
+
+      for (unsigned int i = 0; i < num; i++)
+	{
+	  class expand_operand ops[3];
+	  rtx result;
+	  if (num == 1)
+	    result = dest;
+	  else if (i == 0)
+	    result = gen_lowpart (smode, dest);
+	  else
+	    result = gen_reg_rtx (smode);
+	  create_output_operand (&ops[0], result, smode);
+	  ops[0].target = 1;
+	  create_input_operand (&ops[1], v, vmode);
+	  create_integer_operand (&ops[2], index + i);
+	  expand_insn (icode, 3, ops);
+	  if (ops[0].value != result)
+	    emit_move_insn (result, ops[0].value);
+
+	  if (i == 1)
+	    {
+	      rtx tmp
+		= expand_binop (Pmode, ashl_optab, gen_lowpart (Pmode, result),
+				gen_int_mode (32, Pmode), NULL_RTX, 0,
+				OPTAB_DIRECT);
+	      rtx tmp2 = expand_binop (Pmode, ior_optab, tmp, dest, NULL_RTX, 0,
+				       OPTAB_DIRECT);
+	      emit_move_insn (dest, tmp2);
+	    }
+	}
+      return true;
+    }
   /* Expand
        (set (reg:QI target) (mem:QI (address)))
      to
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/slp-9.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/slp-9.c
index 5fba27c7a35..7c42438c9d9 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/slp-9.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/slp-9.c
@@ -29,4 +29,3 @@
 TEST_ALL (VEC_PERM)
 
 /* { dg-final { scan-assembler-times {viota.m} 2 } } */
-/* { dg-final { scan-assembler-not {vmv\.v\.i} } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-1.c
new file mode 100644
index 00000000000..a7f64c937c6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-1.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -Wno-int-conversion -Wno-implicit-function -Wno-incompatible-pointer-types -Wno-implicit-function-declaration -Ofast -ftree-vectorize" } */
+
+int d ();
+typedef struct
+{
+  int b;
+} c;
+int
+e (char *f, long g)
+{
+  f += g;
+  while (g--)
+    *--f = d;
+}
+
+int
+d (c * f)
+{
+  while (h ())
+    switch (f->b)
+      case 'Q':
+      {
+	long a;
+	e (&a, sizeof (a));
+	i (a);
+      }
+}
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-2.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-2.c
new file mode 100644
index 00000000000..1f170c962e1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr111391-2.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zve32x_zvl128b -mabi=lp64d -Wno-int-conversion -Wno-implicit-function -Wno-incompatible-pointer-types -Wno-implicit-function-declaration -Ofast -ftree-vectorize" } */
+
+#include "pr111391-1.c"
+
+/* { dg-final { scan-assembler-times {vsetivli\s+zero,\s*2,\s*e32,\s*mf2,\s*t[au],\s*m[au]} 1 } }
+/* { dg-final { scan-assembler-times {vmv\.x\.s} 2 } } */
+/* { dg-final { scan-assembler-times {vslidedown.vi\s+v[0-9]+,\s*v[0-9]+,\s*1} 1 } } */
+/* { dg-final { scan-assembler-times {slli\s+[a-x0-9]+,[a-x0-9]+,32} 1 } } */
+/* { dg-final { scan-assembler-times {or\s+[a-x0-9]+,[a-x0-9]+,[a-x0-9]+} 1 } } */