On Thu, Oct 15, 2020 at 8:38 PM Richard Sandiford
<[email protected]> wrote:
>
> Hongtao Liu via Gcc-patches <[email protected]> writes:
> > + /* Simplify vec_select of a subreg of X to just a vec_select of X
> > + when X has same component mode as vec_select. */
> > + int l2;
> > + if (GET_CODE (trueop0) == SUBREG
> > + && GET_MODE_INNER (mode)
> > + == GET_MODE_INNER (GET_MODE (XEXP (trueop0, 0)))
>
> Better to use SUBREG_REG here and below.
>
Yes and changed.
> > + && (GET_MODE_NUNITS (GET_MODE (trueop0))).is_constant (&l0)
> > + && (GET_MODE_NUNITS (mode)).is_constant (&l1)
> > + && (GET_MODE_NUNITS (GET_MODE (XEXP (trueop0, 0))))
> > + .is_constant (&l2)
> > + && known_le (l1, l2))
> > + {
> > + unsigned HOST_WIDE_INT subreg_offset = 0;
> > + gcc_assert (known_eq (XVECLEN (trueop1, 0), l1));
> > + gcc_assert (can_div_trunc_p (exact_div (subreg_lsb (trueop0),
> > BITS_PER_UNIT),
> > + GET_MODE_SIZE (GET_MODE_INNER
> > (mode)),
> > + &subreg_offset));
>
> can_div_trunc_p discards the remainder, whereas it looks like here
> you want an exact multiple.
>
> I don't think it's absolutely guaranteed that the “if” condition makes
> the division by GET_MODE_SIZE exact. E.g. in principle you could have
> a subreg of a vector of TIs in which the subreg offset is misaligned by
> a DI offset.
>
> I'm not sure the subreg_lsb conversion is correct though. On big-endian
> targets, lane numbering follows memory layout, just like subreg byte
> offsets do. So ISTM that using SUBREG_BYTE (as per the earlier patch)
> was correct.
>
> In summary, I think the "if” condition should include something like:
>
> constant_mulitple_p (SUBREG_BYTE (trueop0),
> GET_MODE_UNIT_BITSIZE (mode),
> &subreg_offset)
>
Changed.
> Thanks,
> Richard
Update patch.
--
BR,
Hongtao
From 8d154067963e453c337e6dc2c4f3f19bf0d6e11b Mon Sep 17 00:00:00 2001
From: liuhongt <[email protected]>
Date: Tue, 13 Oct 2020 15:35:29 +0800
Subject: [PATCH] Simplify vec_select of a subreg of X to just a vec_select of
X.
gcc/ChangeLog
PR rtl-optimization/97249
* simplify-rtx.c (simplify_binary_operation_1): Simplify
vec_select of a subreg of X to a vec_select of X.
gcc/testsuite/ChangeLog
* gcc.target/i386/pr97249-1.c: New test.
---
gcc/simplify-rtx.c | 44 +++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/pr97249-1.c | 30 ++++++++++++++++
2 files changed, 74 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/i386/pr97249-1.c
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 869f0d11b2e..b1009837b2b 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -4170,6 +4170,50 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
return subop1;
}
}
+
+ /* Simplify vec_select of a subreg of X to just a vec_select of X
+ when X has same component mode as vec_select. */
+ int l2;
+ unsigned HOST_WIDE_INT subreg_offset = 0;
+ if (GET_CODE (trueop0) == SUBREG
+ && GET_MODE_INNER (mode)
+ == GET_MODE_INNER (GET_MODE (SUBREG_REG (trueop0)))
+ && (GET_MODE_NUNITS (GET_MODE (trueop0))).is_constant (&l0)
+ && (GET_MODE_NUNITS (mode)).is_constant (&l1)
+ && (GET_MODE_NUNITS (GET_MODE (SUBREG_REG (trueop0))))
+ .is_constant (&l2)
+ && known_le (l1, l2)
+ && constant_multiple_p (SUBREG_BYTE (trueop0),
+ GET_MODE_UNIT_BITSIZE (mode),
+ &subreg_offset))
+ {
+
+ gcc_assert (known_eq (XVECLEN (trueop1, 0), l1));
+ bool success = true;
+ for (int i = 0; i != l1; i++)
+ {
+ rtx idx = XVECEXP (trueop1, 0, i);
+ if (!CONST_INT_P (idx))
+ {
+ success = false;
+ break;
+ }
+ }
+ if (success)
+ {
+ rtx par = trueop1;
+ if (subreg_offset)
+ {
+ rtvec vec = rtvec_alloc (l1);
+ for (int i = 0; i < l1; i++)
+ RTVEC_ELT (vec, i)
+ = GEN_INT (INTVAL (XVECEXP (trueop1, 0, i)
+ + subreg_offset));
+ par = gen_rtx_PARALLEL (VOIDmode, vec);
+ }
+ return gen_rtx_VEC_SELECT (mode, SUBREG_REG (trueop0), par);
+ }
+ }
}
if (XVECLEN (trueop1, 0) == 1
diff --git a/gcc/testsuite/gcc.target/i386/pr97249-1.c b/gcc/testsuite/gcc.target/i386/pr97249-1.c
new file mode 100644
index 00000000000..4478a34a9f8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr97249-1.c
@@ -0,0 +1,30 @@
+/* PR target/97249 */
+/* { dg-do compile } */
+/* { dg-options "-mavx2 -O3 -masm=att" } */
+/* { dg-final { scan-assembler-times {(?n)vpmovzxbw[ \t]+\(.*%xmm[0-9]} 2 } } */
+/* { dg-final { scan-assembler-times {(?n)vpmovzxwd[ \t]+\(.*%xmm[0-9]} 2 } } */
+/* { dg-final { scan-assembler-times {(?n)vpmovzxdq[ \t]+\(.*%xmm[0-9]} 2 } } */
+
+void
+foo (unsigned char* p1, unsigned char* p2, short* __restrict p3)
+{
+ for (int i = 0 ; i != 8; i++)
+ p3[i] = p1[i] + p2[i];
+ return;
+}
+
+void
+foo1 (unsigned short* p1, unsigned short* p2, int* __restrict p3)
+{
+ for (int i = 0 ; i != 4; i++)
+ p3[i] = p1[i] + p2[i];
+ return;
+}
+
+void
+foo2 (unsigned int* p1, unsigned int* p2, long long* __restrict p3)
+{
+ for (int i = 0 ; i != 2; i++)
+ p3[i] = (long long)p1[i] + (long long)p2[i];
+ return;
+}
--
2.18.1
