1b5f74e8be
This PR is caused by POLY_INT_CSTs being (necessarily) valid
in tree-level VECTOR_CSTs but CONST_POLY_INTs not being valid
in RTL CONST_VECTORs. I can't tell/remember how deliberate
that was, but I'm guessing not very. In particular,
valid_for_const_vector_p was added to guard against symbolic
constants rather than CONST_POLY_INTs.
I did briefly consider whether we should maintain the current
status anyway. However, that would then require a way of
constructing variable-length vectors from individiual elements
if, say, we have:
{ [2, 2], [3, 2], [4, 2], … }
So I'm chalking this up to an oversight. I think the intention
(and certainly the natural thing) is to have the same rules for
both trees and RTL.
The SVE CONST_VECTOR code should already be set up to handle
CONST_POLY_INTs. However, we need to add support for Advanced SIMD
CONST_VECTORs that happen to contain SVE-based values. The patch does
that by expanding such CONST_VECTORs in the same way as variable vectors.
gcc/
PR rtl-optimization/97141
PR rtl-optimization/98726
* emit-rtl.c (valid_for_const_vector_p): Return true for
CONST_POLY_INT_P.
* rtx-vector-builder.h (rtx_vector_builder::step): Return a
poly_wide_int instead of a wide_int.
(rtx_vector_builder::apply_set): Take a poly_wide_int instead
of a wide_int.
* rtx-vector-builder.c (rtx_vector_builder::apply_set): Likewise.
* config/aarch64/aarch64.c (aarch64_legitimate_constant_p): Return
false for CONST_VECTORs that cannot be forced to memory.
* config/aarch64/aarch64-simd.md (mov<mode>): If a CONST_VECTOR
is too complex to force to memory, build it up from individual
elements instead.
gcc/testsuite/
PR rtl-optimization/97141
PR rtl-optimization/98726
* gcc.c-torture/compile/pr97141.c: New test.
* gcc.c-torture/compile/pr98726.c: Likewise.
* gcc.target/aarch64/sve/pr97141.c: Likewise.
* gcc.target/aarch64/sve/pr98726.c: Likewise.
113 lines
3.0 KiB
C
113 lines
3.0 KiB
C
/* A class for building vector rtx constants.
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Copyright (C) 2017-2021 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "rtl.h"
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#include "rtx-vector-builder.h"
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/* Return a CONST_VECTOR for the current constant. V is an existing
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rtvec that contains all the elements. */
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rtx
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rtx_vector_builder::build (rtvec v)
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{
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finalize ();
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rtx x = find_cached_value ();
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if (x)
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return x;
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x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
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CONST_VECTOR_NPATTERNS (x) = npatterns ();
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CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
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return x;
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}
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/* Return a vector element with the value BASE + FACTOR * STEP. */
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rtx
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rtx_vector_builder::apply_step (rtx base, unsigned int factor,
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const poly_wide_int &step) const
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{
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scalar_int_mode int_mode = as_a <scalar_int_mode> (GET_MODE_INNER (m_mode));
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return immed_wide_int_const (wi::to_poly_wide (base, int_mode)
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+ factor * step,
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int_mode);
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}
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/* Return a CONST_VECTOR for the current constant. */
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rtx
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rtx_vector_builder::build ()
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{
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finalize ();
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rtx x = find_cached_value ();
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if (x)
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return x;
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unsigned int nelts;
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if (!GET_MODE_NUNITS (m_mode).is_constant (&nelts))
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nelts = encoded_nelts ();
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rtvec v = rtvec_alloc (nelts);
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for (unsigned int i = 0; i < nelts; ++i)
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RTVEC_ELT (v, i) = elt (i);
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x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
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CONST_VECTOR_NPATTERNS (x) = npatterns ();
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CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
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return x;
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}
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/* Check whether there is a global cached value for the vector.
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Return it if so, otherwise return null. */
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rtx
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rtx_vector_builder::find_cached_value ()
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{
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if (encoded_nelts () != 1)
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return NULL_RTX;
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rtx elt = (*this)[0];
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if (GET_MODE_CLASS (m_mode) == MODE_VECTOR_BOOL)
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{
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if (elt == const1_rtx || elt == constm1_rtx)
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return CONST1_RTX (m_mode);
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else if (elt == const0_rtx)
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return CONST0_RTX (m_mode);
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else
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gcc_unreachable ();
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}
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/* We can be called before the global vector constants are set up,
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but in that case we'll just return null. */
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scalar_mode inner_mode = GET_MODE_INNER (m_mode);
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if (elt == CONST0_RTX (inner_mode))
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return CONST0_RTX (m_mode);
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else if (elt == CONST1_RTX (inner_mode))
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return CONST1_RTX (m_mode);
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else if (elt == CONSTM1_RTX (inner_mode))
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return CONSTM1_RTX (m_mode);
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return NULL_RTX;
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}
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