Hi, Richard.
After investigating the codes:
/* Return true if EXPR is the integer constant zero or a complex constant
of zero, or a location wrapper for such a constant. */
bool
integer_zerop (const_tree expr)
{
STRIP_ANY_LOCATION_WRAPPER (expr);
switch (TREE_CODE (expr))
{
case INTEGER_CST:
return wi::to_wide (expr) == 0;
case COMPLEX_CST:
return (integer_zerop (TREE_REALPART (expr))
&& integer_zerop (TREE_IMAGPART (expr)));
case VECTOR_CST:
return (VECTOR_CST_NPATTERNS (expr) == 1
&& VECTOR_CST_DUPLICATE_P (expr)
&& integer_zerop (VECTOR_CST_ENCODED_ELT (expr, 0)));
default:
return false;
}
}
I wonder whether we can simplify the codes as follows :?
if (integer_zerop (arg1) || integer_zerop (arg2))
step_ok_p = (code == BIT_AND_EXPR || code == BIT_IOR_EXPR
|| code == BIT_XOR_EXPR);
juzhe.zh...@rivai.ai
From: Richard Biener
Date: 2023-12-19 17:12
To: juzhe.zh...@rivai.ai
CC: Robin Dapp; gcc-patches; pan2.li; richard.sandiford; Richard Biener; pinskia
Subject: Re: Re: [PATCH] fold-const: Handle AND, IOR, XOR with stepped vectors
[PR112971].
On Tue, 19 Dec 2023, juzhe.zh...@rivai.ai wrote:
> Hi?Richard. Do you mean add the check as follows ?
>
> if (VECTOR_CST_NELTS_PER_PATTERN (arg1) == 1
> && VECTOR_CST_NELTS_PER_PATTERN (arg2) == 3
Or <= 3 which would allow combining. As said, not sure what
== 2 would be and whether that would work.
Btw, integer_allonesp should also allow to be optimized for
and/ior at least. Possibly IOR/AND with the sign bit for
signed elements as well.
I wonder if there's a programmatic way to identify OK cases
rather than enumerating them.
> && integer_zerop (VECTOR_CST_ELT (arg1, 0)))
> step_ok_p = (code == BIT_AND_EXPR || code == BIT_IOR_EXPR
> || code == BIT_XOR_EXPR);
> else if (VECTOR_CST_NELTS_PER_PATTERN (arg2) == 1
> && VECTOR_CST_NELTS_PER_PATTERN (arg1) == 3
> && integer_zerop (VECTOR_CST_ELT (arg2, 0)))
> step_ok_p = (code == BIT_AND_EXPR || code == BIT_IOR_EXPR
> || code == BIT_XOR_EXPR);
>
>
>
> juzhe.zh...@rivai.ai
>
> From: Richard Biener
> Date: 2023-12-19 16:15
> To: ???
> CC: rdapp.gcc; gcc-patches; pan2.li; richard.sandiford; richard.guenther;
> Andrew Pinski
> Subject: Re: [PATCH] fold-const: Handle AND, IOR, XOR with stepped vectors
> [PR112971].
> On Tue, 19 Dec 2023, ??? wrote:
>
> > Thanks Robin send initial patch to fix this ICE bug.
> >
> > CC to Richard S, Richard B, and Andrew.
>
> Just one comment, it seems that VECTOR_CST_STEPPED_P should
> implicitly include VECTOR_CST_DUPLICATE_P since it would be
> a step of zero (but as implemented it doesn't catch this).
> Looking at the implementation it's odd that we can handle
> VECTOR_CST_NELTS_PER_PATTERN == 1 (duplicate) and
> == 3 (stepped) but not == 2 (not sure what that would be).
>
> Maybe the tests can be re-formulated in terms of
> VECTOR_CST_NELTS_PER_PATTERN?
>
> Richard.
>
> > Thanks.
> >
> >
> >
> > juzhe.zh...@rivai.ai
> >
> > From: Robin Dapp
> > Date: 2023-12-19 03:50
> > To: gcc-patches
> > CC: rdapp.gcc; Li, Pan2; juzhe.zh...@rivai.ai
> > Subject: [PATCH] fold-const: Handle AND, IOR, XOR with stepped vectors
> > [PR112971].
> > Hi,
> >
> > found in PR112971, this patch adds folding support for bitwise operations
> > of const duplicate zero vectors and stepped vectors.
> > On riscv we have the situation that a folding would perpetually continue
> > without simplifying because e.g. {0, 0, 0, ...} & {7, 6, 5, ...} would
> > not fold to {0, 0, 0, ...}.
> >
> > Bootstrapped and regtested on x86 and aarch64, regtested on riscv.
> >
> > I won't be available to respond quickly until next year. Pan or Juzhe,
> > as discussed, feel free to continue with possible revisions.
> >
> > Regards
> > Robin
> >
> >
> > gcc/ChangeLog:
> >
> > PR middle-end/112971
> >
> > * fold-const.cc (const_binop): Handle
> > zerop@1 AND/IOR/XOR VECT_CST_STEPPED_P@2
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.target/riscv/rvv/autovec/pr112971.c: New test.
> > ---
> > gcc/fold-const.cc | 14 +++++++++++++-
> > .../gcc.target/riscv/rvv/autovec/pr112971.c | 18 ++++++++++++++++++
> > 2 files changed, 31 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112971.c
> >
> > diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
> > index f5d68ac323a..43ed097bf5c 100644
> > --- a/gcc/fold-const.cc
> > +++ b/gcc/fold-const.cc
> > @@ -1653,8 +1653,20 @@ const_binop (enum tree_code code, tree arg1, tree
> > arg2)
> > {
> > tree type = TREE_TYPE (arg1);
> > bool step_ok_p;
> > +
> > + /* AND, IOR as well as XOR with a zerop can be handled directly. */
> > if (VECTOR_CST_STEPPED_P (arg1)
> > - && VECTOR_CST_STEPPED_P (arg2))
> > + && VECTOR_CST_DUPLICATE_P (arg2)
> > + && integer_zerop (VECTOR_CST_ELT (arg2, 0)))
> > + step_ok_p = code == BIT_AND_EXPR || code == BIT_IOR_EXPR
> > + || code == BIT_XOR_EXPR;
> > + else if (VECTOR_CST_STEPPED_P (arg2)
> > + && VECTOR_CST_DUPLICATE_P (arg1)
> > + && integer_zerop (VECTOR_CST_ELT (arg1, 0)))
> > + step_ok_p = code == BIT_AND_EXPR || code == BIT_IOR_EXPR
> > + || code == BIT_XOR_EXPR;
> > + else if (VECTOR_CST_STEPPED_P (arg1)
> > + && VECTOR_CST_STEPPED_P (arg2))
> > /* We can operate directly on the encoding if:
> > a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
> > diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112971.c
> > b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112971.c
> > new file mode 100644
> > index 00000000000..816ebd3c493
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112971.c
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-march=rv64gcv_zvl256b -mabi=lp64d -O3
> > -fno-vect-cost-model" } */
> > +
> > +int a;
> > +short b[9];
> > +char c, d;
> > +void e() {
> > + d = 0;
> > + for (;; d++) {
> > + if (b[d])
> > + break;
> > + a = 8;
> > + for (; a >= 0; a--) {
> > + char *f = &c;
> > + *f &= d == (a & d);
> > + }
> > + }
> > +}
> >
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
