Re: [PATCH] RISC-V: Bugfix for RTL check[PR111533]

[juzhe.zh...@rivai.ai]

+      vid sequence.  The elt (i) can be either const_int or
+      const_poly_int. */
+   HOST_WIDE_INT diff = rtx_to_poly_int64 (builder.elt (i)).to_constant () - i;

How about:

poly_int64 diff = rtx_to_poly_int64 (builder.elt (i)) - i;

       rtx avl
- = has_vl_op (insn->rtl ()) ? get_vl (insn->rtl ()) : dem.get_avl ();
+ = (has_vl_op (insn->rtl ()) && REG_P (get_vl (insn->rtl ())))
+   ? get_vl (insn->rtl ())
+   : dem.get_avl ();

How about:

rtx avl = dem.get_avl_or_vl_reg ();

I wonder whether it is possible add a testcase for this issue ?


juzhe.zh...@rivai.ai
 
From: Li Xu
Date: 2023-09-27 11:07
To: gcc-patches
CC: kito.cheng; palmer; juzhe.zhong; xuli
Subject: [PATCH] RISC-V: Bugfix for RTL check[PR111533]
From: xuli <xu...@eswincomputing.com>
 
Consider the flowing situation:
BB5: local_dem(RVV Insn 1, AVL(reg zero))
RVV Insn 1: vmv.s.x, AVL (const_int 1)
RVV Insn 2: vredsum.vs, AVL(reg zero)
 
vmv.s.x has vl operand, the following code will get
avl (cosnt_int) from RVV Insn 1.
rtx avl = has_vl_op (insn->rtl ()) ? get_vl (insn->rtl ())
                                   : dem.get_avl ();
 
If use REGNO for const_int, the compiler will crash:
 
during RTL pass: vsetvl
res_debug.c: In function '__dn_count_labels':
res_debug.c:1050:1: internal compiler error: RTL check: expected code 'reg',
have 'const_int' in rhs_regno, at rtl.h:1934
1050 | }
      | ^
0x8fb169 rtl_check_failed_code1(rtx_def const*, rtx_code, char const*, int, 
char const*)
../.././gcc/gcc/rtl.cc:770
0x1399818 rhs_regno(rtx_def const*)
../.././gcc/gcc/rtl.h:1934
0x1399818 anticipatable_occurrence_p
../.././gcc/gcc/config/riscv/riscv-vsetvl.cc:348
 
So in this case avl should be obtained from dem.
 
Another issue is caused by the following code:
HOST_WIDE_INT diff = INTVAL (builder.elt (i)) - i;
 
during RTL pass: expand
../../.././gcc/libgfortran/generated/matmul_c4.c: In function 'matmul_c4':
../../.././gcc/libgfortran/generated/matmul_c4.c:2906:39: internal compiler 
error: RTL check:
expected code 'const_int', have 'const_poly_int' in expand_const_vector,
at config/riscv/riscv-v.cc:1149
 
The builder.elt (i) can be either const_int or const_poly_int.
PR target/111533
gcc/ChangeLog:
 
* config/riscv/riscv-v.cc (expand_const_vector): Fix bug.
* config/riscv/riscv-vsetvl.cc (anticipatable_occurrence_p): Fix bug.
---
gcc/config/riscv/riscv-v.cc      | 6 ++++--
gcc/config/riscv/riscv-vsetvl.cc | 5 ++++-
2 files changed, 8 insertions(+), 3 deletions(-)
 
diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index 5f738634219..fb3c55b4705 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -1147,8 +1147,10 @@ expand_const_vector (rtx target, rtx src)
      for (unsigned int i = 0; i < v.npatterns (); ++i)
{
  /* Calculate the diff between the target sequence and
-      vid sequence.  */
-   HOST_WIDE_INT diff = INTVAL (builder.elt (i)) - i;
+      vid sequence.  The elt (i) can be either const_int or
+      const_poly_int. */
+   HOST_WIDE_INT diff = rtx_to_poly_int64 (builder.elt (i)).to_constant () - i;
+
  v.quick_push (gen_int_mode (diff, v.inner_mode ()));
}
      /* Step 2: Generate result = VID + diff.  */
diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index 7af33e7ea6f..27000434341 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -308,7 +308,10 @@ anticipatable_occurrence_p (const bb_info *bb, const 
vector_insn_info dem)
     {
       /* rs1 (avl) are not modified in the basic block prior to the VSETVL.  */
       rtx avl
- = has_vl_op (insn->rtl ()) ? get_vl (insn->rtl ()) : dem.get_avl ();
+ = (has_vl_op (insn->rtl ()) && REG_P (get_vl (insn->rtl ())))
+   ? get_vl (insn->rtl ())
+   : dem.get_avl ();
+
       if (dem.dirty_p ())
{
  gcc_assert (!vsetvl_insn_p (insn->rtl ()));
-- 
2.17.1