On Thu, Dec 28, 2017 at 9:51 PM, Richard Sandiford
<richard.sandif...@linaro.org> wrote:
> This patch makes CONST_VECTOR use the same encoding as VECTOR_CST.
>
> One problem that occurs in RTL but not at the tree level is that a fair
> amount of code uses XVEC and XVECEXP directly on CONST_VECTORs (which is
> valid, just with looser checking). This is complicated by the fact that
> vectors are also represented as PARALLELs in some target interfaces,
> so using XVECEXP is a good polymorphic way of handling both forms.
>
> Rather than try to untangle all that, the best approach seemed to be to
> continue to encode every element in a fixed-length vector. That way only
> target-independent and AArch64 code need to be precise about using
> CONST_VECTOR_ELT over XVECEXP.
>
> After this change is no longer valid to modify CONST_VECTORs in-place.
> This needed some fix-up in the powerpc backends.
Ok.
Richard.
> 2017-12-28 Richard Sandiford <richard.sandif...@linaro.org>
>
> gcc/
> * doc/rtl.texi (const_vector): Describe new encoding scheme.
> * Makefile.in (OBJS): Add rtx-vector-builder.o.
> * rtx-vector-builder.h: New file.
> * rtx-vector-builder.c: Likewise.
> * rtl.h (rtx_def::u2): Add a const_vector field.
> (CONST_VECTOR_NPATTERNS): New macro.
> (CONST_VECTOR_NELTS_PER_PATTERN): Likewise.
> (CONST_VECTOR_DUPLICATE_P): Likewise.
> (CONST_VECTOR_STEPPED_P): Likewise.
> (CONST_VECTOR_ENCODED_ELT): Likewise.
> (const_vec_duplicate_p): Check for a duplicated vector encoding.
> (unwrap_const_vec_duplicate): Likewise.
> (const_vec_series_p): Check for a non-duplicated vector encoding.
> Say that the function only returns true for integer vectors.
> * emit-rtl.c: Include rtx-vector-builder.h.
> (gen_const_vec_duplicate_1): Delete.
> (gen_const_vector): Call gen_const_vec_duplicate instead of
> gen_const_vec_duplicate_1.
> (const_vec_series_p_1): Operate directly on the CONST_VECTOR encoding.
> (gen_const_vec_duplicate): Use rtx_vector_builder.
> (gen_const_vec_series): Likewise.
> (gen_rtx_CONST_VECTOR): Likewise.
> * config/powerpcspe/powerpcspe.c: Include rtx-vector-builder.h.
> (swap_const_vector_halves): Take an rtx pointer rather than rtx.
> Build a new vector rather than modifying a CONST_VECTOR in-place.
> (handle_special_swappables): Update call accordingly.
> * config/rs6000/rs6000-p8swap.c: Include rtx-vector-builder.h.
> (swap_const_vector_halves): Take an rtx pointer rather than rtx.
> Build a new vector rather than modifying a CONST_VECTOR in-place.
> (handle_special_swappables): Update call accordingly.
>
> Index: gcc/doc/rtl.texi
> ===================================================================
> --- gcc/doc/rtl.texi 2017-12-22 16:54:11.793940998 +0000
> +++ gcc/doc/rtl.texi 2017-12-28 16:58:43.018987597 +0000
> @@ -1644,18 +1644,92 @@ low-level routines) and @code{const_poly
>
> @findex const_vector
> @item (const_vector:@var{m} [@var{x0} @var{x1} @dots{}])
> -Represents a vector constant. The square brackets stand for the vector
> -containing the constant elements. @var{x0}, @var{x1} and so on are
> -the @code{const_int}, @code{const_wide_int}, @code{const_double} or
> -@code{const_fixed} elements.
> -
> -The number of units in a @code{const_vector} is obtained with the macro
> -@code{CONST_VECTOR_NUNITS} as in @code{CONST_VECTOR_NUNITS (@var{v})}.
> -
> -Individual elements in a vector constant are accessed with the macro
> -@code{CONST_VECTOR_ELT} as in @code{CONST_VECTOR_ELT (@var{v}, @var{n})}
> -where @var{v} is the vector constant and @var{n} is the element
> -desired.
> +Represents a vector constant. The values in square brackets are
> +elements of the vector, which are always @code{const_int},
> +@code{const_wide_int}, @code{const_double} or @code{const_fixed}
> +expressions.
> +
> +Each vector constant @var{v} is treated as a specific instance of an
> +arbitrary-length sequence that itself contains
> +@samp{CONST_VECTOR_NPATTERNS (@var{v})} interleaved patterns. Each
> +pattern has the form:
> +
> +@smallexample
> +@{ @var{base0}, @var{base1}, @var{base1} + @var{step}, @var{base1} +
> @var{step} * 2, @dots{} @}
> +@end smallexample
> +
> +The first three elements in each pattern are enough to determine the
> +values of the other elements. However, if all @var{step}s are zero,
> +only the first two elements are needed. If in addition each @var{base1}
> +is equal to the corresponding @var{base0}, only the first element in
> +each pattern is needed. The number of determining elements per pattern
> +is given by @samp{CONST_VECTOR_NELTS_PER_PATTERN (@var{v})}.
> +
> +For example, the constant:
> +
> +@smallexample
> +@{ 0, 1, 2, 6, 3, 8, 4, 10, 5, 12, 6, 14, 7, 16, 8, 18 @}
> +@end smallexample
> +
> +is interpreted as an interleaving of the sequences:
> +
> +@smallexample
> +@{ 0, 2, 3, 4, 5, 6, 7, 8 @}
> +@{ 1, 6, 8, 10, 12, 14, 16, 18 @}
> +@end smallexample
> +
> +where the sequences are represented by the following patterns:
> +
> +@smallexample
> +@var{base0} == 0, @var{base1} == 2, @var{step} == 1
> +@var{base0} == 1, @var{base1} == 6, @var{step} == 2
> +@end smallexample
> +
> +In this case:
> +
> +@smallexample
> +CONST_VECTOR_NPATTERNS (@var{v}) == 2
> +CONST_VECTOR_NELTS_PER_PATTERN (@var{v}) == 3
> +@end smallexample
> +
> +Thus the first 6 elements (@samp{@{ 0, 1, 2, 6, 3, 8 @}}) are enough
> +to determine the whole sequence; we refer to them as the ``encoded''
> +elements. They are the only elements present in the square brackets
> +for variable-length @code{const_vector}s (i.e. for
> +@code{const_vector}s whose mode @var{m} has a variable number of
> +elements). However, as a convenience to code that needs to handle
> +both @code{const_vector}s and @code{parallel}s, all elements are
> +present in the square brackets for fixed-length @code{const_vector}s;
> +the encoding scheme simply reduces the amount of work involved in
> +processing constants that follow a regular pattern.
> +
> +Sometimes this scheme can create two possible encodings of the same
> +vector. For example @{ 0, 1 @} could be seen as two patterns with
> +one element each or one pattern with two elements (@var{base0} and
> +@var{base1}). The canonical encoding is always the one with the
> +fewest patterns or (if both encodings have the same number of
> +petterns) the one with the fewest encoded elements.
> +
> +@samp{const_vector_encoding_nelts (@var{v})} gives the total number of
> +encoded elements in @var{v}, which is 6 in the example above.
> +@code{CONST_VECTOR_ENCODED_ELT (@var{v}, @var{i})} accesses the value
> +of encoded element @var{i}.
> +
> +@samp{CONST_VECTOR_DUPLICATE_P (@var{v})} is true if @var{v} simply contains
> +repeated instances of @samp{CONST_VECTOR_NPATTERNS (@var{v})} values. This
> is
> +a shorthand for testing @samp{CONST_VECTOR_NELTS_PER_PATTERN (@var{v}) == 1}.
> +
> +@samp{CONST_VECTOR_STEPPED_P (@var{v})} is true if at least one
> +pattern in @var{v} has a nonzero step. This is a shorthand for
> +testing @samp{CONST_VECTOR_NELTS_PER_PATTERN (@var{v}) == 3}.
> +
> +@code{CONST_VECTOR_NUNITS (@var{v})} gives the total number of elements
> +in @var{v}; it is a shorthand for getting the number of units in
> +@samp{GET_MODE (@var{v})}.
> +
> +The utility function @code{const_vector_elt} gives the value of an
> +arbitrary element as an @code{rtx}. @code{const_vector_int_elt} gives
> +the same value as a @code{wide_int}.
>
> @findex const_string
> @item (const_string @var{str})
> Index: gcc/Makefile.in
> ===================================================================
> --- gcc/Makefile.in 2017-12-28 16:57:58.744157771 +0000
> +++ gcc/Makefile.in 2017-12-28 16:58:43.014988604 +0000
> @@ -1453,6 +1453,7 @@ OBJS = \
> rtlhash.o \
> rtlanal.o \
> rtlhooks.o \
> + rtx-vector-builder.o \
> run-rtl-passes.o \
> sched-deps.o \
> sched-ebb.o \
> Index: gcc/rtx-vector-builder.h
> ===================================================================
> --- /dev/null 2017-12-28 10:25:58.775409153 +0000
> +++ gcc/rtx-vector-builder.h 2017-12-28 16:58:43.020987093 +0000
> @@ -0,0 +1,115 @@
> +/* A class for building vector rtx constants.
> + Copyright (C) 2017 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3. If not see
> +<http://www.gnu.org/licenses/>. */
> +
> +#ifndef GCC_RTX_VECTOR_BUILDER_H
> +#define GCC_RTX_VECTOR_BUILDER_H
> +
> +#include "vector-builder.h"
> +
> +/* This class is used to build VECTOR_CSTs from a sequence of elements.
> + See vector_builder for more details. */
> +class rtx_vector_builder : public vector_builder<rtx, rtx_vector_builder>
> +{
> + typedef vector_builder<rtx, rtx_vector_builder> parent;
> + friend class vector_builder<rtx, rtx_vector_builder>;
> +
> +public:
> + rtx_vector_builder () : m_mode (VOIDmode) {}
> + rtx_vector_builder (machine_mode, unsigned int, unsigned int);
> + rtx build (rtvec);
> + rtx build ();
> +
> + machine_mode mode () const { return m_mode; }
> +
> + void new_vector (machine_mode, unsigned int, unsigned int);
> +
> +private:
> + bool equal_p (rtx, rtx) const;
> + bool allow_steps_p () const;
> + bool integral_p (rtx) const;
> + wide_int step (rtx, rtx) const;
> + rtx apply_step (rtx, unsigned int, const wide_int &) const;
> + bool can_elide_p (rtx) const { return true; }
> + void note_representative (rtx *, rtx) {}
> +
> + rtx find_cached_value ();
> +
> + machine_mode m_mode;
> +};
> +
> +/* Create a new builder for a vector of mode MODE. Initially encode the
> + value as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements
> + each. */
> +
> +inline
> +rtx_vector_builder::rtx_vector_builder (machine_mode mode,
> + unsigned int npatterns,
> + unsigned int nelts_per_pattern)
> +{
> + new_vector (mode, npatterns, nelts_per_pattern);
> +}
> +
> +/* Start building a new vector of mode MODE. Initially encode the value
> + as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
> */
> +
> +inline void
> +rtx_vector_builder::new_vector (machine_mode mode, unsigned int npatterns,
> + unsigned int nelts_per_pattern)
> +{
> + m_mode = mode;
> + parent::new_vector (GET_MODE_NUNITS (mode), npatterns, nelts_per_pattern);
> +}
> +
> +/* Return true if elements ELT1 and ELT2 are equal. */
> +
> +inline bool
> +rtx_vector_builder::equal_p (rtx elt1, rtx elt2) const
> +{
> + return rtx_equal_p (elt1, elt2);
> +}
> +
> +/* Return true if a stepped representation is OK. We don't allow
> + linear series for anything other than integers, to avoid problems
> + with rounding. */
> +
> +inline bool
> +rtx_vector_builder::allow_steps_p () const
> +{
> + return is_a <scalar_int_mode> (GET_MODE_INNER (m_mode));
> +}
> +
> +/* Return true if element ELT can be interpreted as an integer. */
> +
> +inline bool
> +rtx_vector_builder::integral_p (rtx elt) const
> +{
> + return CONST_SCALAR_INT_P (elt);
> +}
> +
> +/* Return the value of element ELT2 minus the value of element ELT1.
> + Both elements are known to be CONST_SCALAR_INT_Ps. */
> +
> +inline wide_int
> +rtx_vector_builder::step (rtx elt1, rtx elt2) const
> +{
> + return wi::sub (rtx_mode_t (elt2, GET_MODE_INNER (m_mode)),
> + rtx_mode_t (elt1, GET_MODE_INNER (m_mode)));
> +}
> +
> +#endif
> Index: gcc/rtx-vector-builder.c
> ===================================================================
> --- /dev/null 2017-12-28 10:25:58.775409153 +0000
> +++ gcc/rtx-vector-builder.c 2017-12-28 16:58:43.020987093 +0000
> @@ -0,0 +1,100 @@
> +/* A class for building vector rtx constants.
> + Copyright (C) 2017 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3. If not see
> +<http://www.gnu.org/licenses/>. */
> +
> +#include "config.h"
> +#include "system.h"
> +#include "coretypes.h"
> +#include "tm.h"
> +#include "rtl.h"
> +#include "rtx-vector-builder.h"
> +
> +/* Return a CONST_VECTOR for the current constant. V is an existing
> + rtvec that contains all the elements. */
> +
> +rtx
> +rtx_vector_builder::build (rtvec v)
> +{
> + finalize ();
> +
> + rtx x = find_cached_value ();
> + if (x)
> + return x;
> +
> + x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
> + CONST_VECTOR_NPATTERNS (x) = npatterns ();
> + CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
> + return x;
> +}
> +
> +/* Return a vector element with the value BASE + FACTOR * STEP. */
> +
> +rtx
> +rtx_vector_builder::apply_step (rtx base, unsigned int factor,
> + const wide_int &step) const
> +{
> + scalar_int_mode int_mode = as_a <scalar_int_mode> (GET_MODE_INNER
> (m_mode));
> + return immed_wide_int_const (wi::add (rtx_mode_t (base, int_mode),
> + factor * step),
> + int_mode);
> +}
> +
> +/* Return a CONST_VECTOR for the current constant. */
> +
> +rtx
> +rtx_vector_builder::build ()
> +{
> + finalize ();
> +
> + rtx x = find_cached_value ();
> + if (x)
> + return x;
> +
> + unsigned int nelts = GET_MODE_NUNITS (m_mode);
> + rtvec v = rtvec_alloc (nelts);
> + for (unsigned int i = 0; i < nelts; ++i)
> + RTVEC_ELT (v, i) = elt (i);
> + x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
> + CONST_VECTOR_NPATTERNS (x) = npatterns ();
> + CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
> + return x;
> +}
> +
> +/* Check whether there is a global cached value for the vector.
> + Return it if so, otherwise return null. */
> +
> +rtx
> +rtx_vector_builder::find_cached_value ()
> +{
> + if (encoded_nelts () != 1)
> + return NULL_RTX;
> +
> + rtx elt = (*this)[0];
> +
> + /* We can be called before the global vector constants are set up,
> + but in that case we'll just return null. */
> + scalar_mode inner_mode = GET_MODE_INNER (m_mode);
> + if (elt == CONST0_RTX (inner_mode))
> + return CONST0_RTX (m_mode);
> + else if (elt == CONST1_RTX (inner_mode))
> + return CONST1_RTX (m_mode);
> + else if (elt == CONSTM1_RTX (inner_mode))
> + return CONSTM1_RTX (m_mode);
> +
> + return NULL_RTX;
> +}
> Index: gcc/rtl.h
> ===================================================================
> --- gcc/rtl.h 2017-12-28 16:57:58.744157771 +0000
> +++ gcc/rtl.h 2017-12-28 16:58:43.020987093 +0000
> @@ -418,6 +418,19 @@ struct GTY((desc("0"), tag("0"),
> /* In a CONST_WIDE_INT (aka hwivec_def), this is the number of
> HOST_WIDE_INTs in the hwivec_def. */
> unsigned int num_elem;
> +
> + /* Information about a CONST_VECTOR. */
> + struct
> + {
> + /* The value of CONST_VECTOR_NPATTERNS. */
> + unsigned int npatterns : 16;
> +
> + /* The value of CONST_VECTOR_NELTS_PER_PATTERN. */
> + unsigned int nelts_per_pattern : 8;
> +
> + /* For future expansion. */
> + unsigned int unused : 8;
> + } const_vector;
> } GTY ((skip)) u2;
>
> /* The first element of the operands of this rtx.
> @@ -1958,6 +1971,23 @@ #define CONST_FIXED_VALUE_LOW(r) \
> /* For a CONST_VECTOR, return element #n. */
> #define CONST_VECTOR_ELT(RTX, N) XCVECEXP (RTX, 0, N, CONST_VECTOR)
>
> +/* See rtl.texi for a description of these macros. */
> +#define CONST_VECTOR_NPATTERNS(RTX) \
> + (RTL_FLAG_CHECK1 ("CONST_VECTOR_NPATTERNS", (RTX), CONST_VECTOR) \
> + ->u2.const_vector.npatterns)
> +
> +#define CONST_VECTOR_NELTS_PER_PATTERN(RTX) \
> + (RTL_FLAG_CHECK1 ("CONST_VECTOR_NELTS_PER_PATTERN", (RTX), CONST_VECTOR) \
> + ->u2.const_vector.nelts_per_pattern)
> +
> +#define CONST_VECTOR_DUPLICATE_P(RTX) \
> + (CONST_VECTOR_NELTS_PER_PATTERN (RTX) == 1)
> +
> +#define CONST_VECTOR_STEPPED_P(RTX) \
> + (CONST_VECTOR_NELTS_PER_PATTERN (RTX) == 3)
> +
> +#define CONST_VECTOR_ENCODED_ELT(RTX, N) XCVECEXP (RTX, 0, N, CONST_VECTOR)
> +
> /* For a CONST_VECTOR, return the number of elements in a vector. */
> #define CONST_VECTOR_NUNITS(RTX) XCVECLEN (RTX, 0, CONST_VECTOR)
>
> @@ -2910,7 +2940,9 @@ const_vec_p (const_rtx x)
> inline bool
> const_vec_duplicate_p (const_rtx x)
> {
> - return ((GET_CODE (x) == CONST_VECTOR && rtvec_all_equal_p (XVEC (x, 0)))
> + return ((GET_CODE (x) == CONST_VECTOR
> + && CONST_VECTOR_NPATTERNS (x) == 1
> + && CONST_VECTOR_DUPLICATE_P (x))
> || (GET_CODE (x) == CONST
> && GET_CODE (XEXP (x, 0)) == VEC_DUPLICATE));
> }
> @@ -2922,9 +2954,11 @@ const_vec_duplicate_p (const_rtx x)
> inline bool
> const_vec_duplicate_p (T x, T *elt)
> {
> - if (GET_CODE (x) == CONST_VECTOR && rtvec_all_equal_p (XVEC (x, 0)))
> + if (GET_CODE (x) == CONST_VECTOR
> + && CONST_VECTOR_NPATTERNS (x) == 1
> + && CONST_VECTOR_DUPLICATE_P (x))
> {
> - *elt = CONST_VECTOR_ELT (x, 0);
> + *elt = CONST_VECTOR_ENCODED_ELT (x, 0);
> return true;
> }
> if (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == VEC_DUPLICATE)
> @@ -2957,8 +2991,10 @@ vec_duplicate_p (T x, T *elt)
> inline T
> unwrap_const_vec_duplicate (T x)
> {
> - if (GET_CODE (x) == CONST_VECTOR && rtvec_all_equal_p (XVEC (x, 0)))
> - return CONST_VECTOR_ELT (x, 0);
> + if (GET_CODE (x) == CONST_VECTOR
> + && CONST_VECTOR_NPATTERNS (x) == 1
> + && CONST_VECTOR_DUPLICATE_P (x))
> + return CONST_VECTOR_ENCODED_ELT (x, 0);
> if (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == VEC_DUPLICATE)
> return XEXP (XEXP (x, 0), 0);
> return x;
> @@ -2967,8 +3003,8 @@ unwrap_const_vec_duplicate (T x)
> /* In emit-rtl.c. */
> extern bool const_vec_series_p_1 (const_rtx, rtx *, rtx *);
>
> -/* Return true if X is a constant vector that contains a linear series
> - of the form:
> +/* Return true if X is an integer constant vector that contains a linear
> + series of the form:
>
> { B, B + S, B + 2 * S, B + 3 * S, ... }
>
> @@ -2978,7 +3014,8 @@ extern bool const_vec_series_p_1 (const_
> const_vec_series_p (const_rtx x, rtx *base_out, rtx *step_out)
> {
> if (GET_CODE (x) == CONST_VECTOR
> - && GET_MODE_CLASS (GET_MODE (x)) == MODE_VECTOR_INT)
> + && CONST_VECTOR_NPATTERNS (x) == 1
> + && !CONST_VECTOR_DUPLICATE_P (x))
> return const_vec_series_p_1 (x, base_out, step_out);
> if (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == VEC_SERIES)
> {
> Index: gcc/emit-rtl.c
> ===================================================================
> --- gcc/emit-rtl.c 2017-12-28 16:57:58.744157771 +0000
> +++ gcc/emit-rtl.c 2017-12-28 16:58:43.018987597 +0000
> @@ -60,6 +60,7 @@ Software Foundation; either version 3, o
> #include "stor-layout.h"
> #include "opts.h"
> #include "predict.h"
> +#include "rtx-vector-builder.h"
>
> struct target_rtl default_target_rtl;
> #if SWITCHABLE_TARGET
> @@ -5872,33 +5873,15 @@ valid_for_const_vector_p (machine_mode,
> || CONST_FIXED_P (x));
> }
>
> -/* Like gen_const_vec_duplicate, but ignore const_tiny_rtx. */
> -
> -static rtx
> -gen_const_vec_duplicate_1 (machine_mode mode, rtx el)
> -{
> - int nunits = GET_MODE_NUNITS (mode);
> - rtvec v = rtvec_alloc (nunits);
> - for (int i = 0; i < nunits; ++i)
> - RTVEC_ELT (v, i) = el;
> - return gen_rtx_raw_CONST_VECTOR (mode, v);
> -}
> -
> /* Generate a vector constant of mode MODE in which every element has
> value ELT. */
>
> rtx
> gen_const_vec_duplicate (machine_mode mode, rtx elt)
> {
> - scalar_mode inner_mode = GET_MODE_INNER (mode);
> - if (elt == CONST0_RTX (inner_mode))
> - return CONST0_RTX (mode);
> - else if (elt == CONST1_RTX (inner_mode))
> - return CONST1_RTX (mode);
> - else if (elt == CONSTM1_RTX (inner_mode))
> - return CONSTM1_RTX (mode);
> -
> - return gen_const_vec_duplicate_1 (mode, elt);
> + rtx_vector_builder builder (mode, 1, 1);
> + builder.quick_push (elt);
> + return builder.build ();
> }
>
> /* Return a vector rtx of mode MODE in which every element has value X.
> @@ -5912,28 +5895,44 @@ gen_vec_duplicate (machine_mode mode, rt
> return gen_rtx_VEC_DUPLICATE (mode, x);
> }
>
> -/* A subroutine of const_vec_series_p that handles the case in which
> - X is known to be an integer CONST_VECTOR. */
> +/* A subroutine of const_vec_series_p that handles the case in which:
> +
> + (GET_CODE (X) == CONST_VECTOR
> + && CONST_VECTOR_NPATTERNS (X) == 1
> + && !CONST_VECTOR_DUPLICATE_P (X))
> +
> + is known to hold. */
>
> bool
> const_vec_series_p_1 (const_rtx x, rtx *base_out, rtx *step_out)
> {
> - unsigned int nelts = CONST_VECTOR_NUNITS (x);
> - if (nelts < 2)
> + /* Stepped sequences are only defined for integers, to avoid specifying
> + rounding behavior. */
> + if (GET_MODE_CLASS (GET_MODE (x)) != MODE_VECTOR_INT)
> + return false;
> +
> + /* A non-duplicated vector with two elements can always be seen as a
> + series with a nonzero step. Longer vectors must have a stepped
> + encoding. */
> + if (CONST_VECTOR_NUNITS (x) != 2
> + && !CONST_VECTOR_STEPPED_P (x))
> return false;
>
> + /* Calculate the step between the first and second elements. */
> scalar_mode inner = GET_MODE_INNER (GET_MODE (x));
> rtx base = CONST_VECTOR_ELT (x, 0);
> rtx step = simplify_binary_operation (MINUS, inner,
> - CONST_VECTOR_ELT (x, 1), base);
> + CONST_VECTOR_ENCODED_ELT (x, 1),
> base);
> if (rtx_equal_p (step, CONST0_RTX (inner)))
> return false;
>
> - for (unsigned int i = 2; i < nelts; ++i)
> + /* If we have a stepped encoding, check that the step between the
> + second and third elements is the same as STEP. */
> + if (CONST_VECTOR_STEPPED_P (x))
> {
> rtx diff = simplify_binary_operation (MINUS, inner,
> - CONST_VECTOR_ELT (x, i),
> - CONST_VECTOR_ELT (x, i - 1));
> + CONST_VECTOR_ENCODED_ELT (x, 2),
> + CONST_VECTOR_ENCODED_ELT (x, 1));
> if (!rtx_equal_p (step, diff))
> return false;
> }
> @@ -5952,14 +5951,12 @@ gen_const_vec_series (machine_mode mode,
> gcc_assert (valid_for_const_vector_p (mode, base)
> && valid_for_const_vector_p (mode, step));
>
> - int nunits = GET_MODE_NUNITS (mode);
> - rtvec v = rtvec_alloc (nunits);
> - scalar_mode inner_mode = GET_MODE_INNER (mode);
> - RTVEC_ELT (v, 0) = base;
> - for (int i = 1; i < nunits; ++i)
> - RTVEC_ELT (v, i) = simplify_gen_binary (PLUS, inner_mode,
> - RTVEC_ELT (v, i - 1), step);
> - return gen_rtx_raw_CONST_VECTOR (mode, v);
> + rtx_vector_builder builder (mode, 1, 3);
> + builder.quick_push (base);
> + for (int i = 1; i < 3; ++i)
> + builder.quick_push (simplify_gen_binary (PLUS, GET_MODE_INNER (mode),
> + builder[i - 1], step));
> + return builder.build ();
> }
>
> /* Generate a vector of mode MODE in which element I has the value
> @@ -5990,7 +5987,7 @@ gen_const_vector (machine_mode mode, int
> rtx el = const_tiny_rtx[constant][(int) inner];
> gcc_assert (el);
>
> - return gen_const_vec_duplicate_1 (mode, el);
> + return gen_const_vec_duplicate (mode, el);
> }
>
> /* Generate a vector like gen_rtx_raw_CONST_VEC, but use the zero vector when
> @@ -6005,7 +6002,11 @@ gen_rtx_CONST_VECTOR (machine_mode mode,
> if (rtvec_all_equal_p (v))
> return gen_const_vec_duplicate (mode, RTVEC_ELT (v, 0));
>
> - return gen_rtx_raw_CONST_VECTOR (mode, v);
> + unsigned int nunits = GET_NUM_ELEM (v);
> + rtx_vector_builder builder (mode, nunits, 1);
> + for (unsigned int i = 0; i < nunits; ++i)
> + builder.quick_push (RTVEC_ELT (v, i));
> + return builder.build (v);
> }
>
> /* Initialise global register information required by all functions. */
> Index: gcc/config/powerpcspe/powerpcspe.c
> ===================================================================
> --- gcc/config/powerpcspe/powerpcspe.c 2017-12-28 16:57:58.744157771 +0000
> +++ gcc/config/powerpcspe/powerpcspe.c 2017-12-28 16:58:43.017987848 +0000
> @@ -79,6 +79,7 @@ #define IN_TARGET_CODE 1
> #endif
> #include "case-cfn-macros.h"
> #include "ppc-auxv.h"
> +#include "rtx-vector-builder.h"
>
> /* This file should be included last. */
> #include "target-def.h"
> @@ -42581,23 +42582,24 @@ mark_swaps_for_removal (swap_web_entry *
> }
> }
>
> -/* OP is either a CONST_VECTOR or an expression containing one.
> +/* *OP_PTR is either a CONST_VECTOR or an expression containing one.
> Swap the first half of the vector with the second in the first
> case. Recurse to find it in the second. */
> static void
> -swap_const_vector_halves (rtx op)
> +swap_const_vector_halves (rtx *op_ptr)
> {
> int i;
> + rtx op = *op_ptr;
> enum rtx_code code = GET_CODE (op);
> if (GET_CODE (op) == CONST_VECTOR)
> {
> - int half_units = GET_MODE_NUNITS (GET_MODE (op)) / 2;
> - for (i = 0; i < half_units; ++i)
> - {
> - rtx temp = CONST_VECTOR_ELT (op, i);
> - CONST_VECTOR_ELT (op, i) = CONST_VECTOR_ELT (op, i + half_units);
> - CONST_VECTOR_ELT (op, i + half_units) = temp;
> - }
> + int units = GET_MODE_NUNITS (GET_MODE (op));
> + rtx_vector_builder builder (GET_MODE (op), units, 1);
> + for (i = 0; i < units / 2; ++i)
> + builder.quick_push (CONST_VECTOR_ELT (op, i + units / 2));
> + for (i = 0; i < units / 2; ++i)
> + builder.quick_push (CONST_VECTOR_ELT (op, i));
> + *op_ptr = builder.build ();
> }
> else
> {
> @@ -42605,10 +42607,10 @@ swap_const_vector_halves (rtx op)
> const char *fmt = GET_RTX_FORMAT (code);
> for (i = 0; i < GET_RTX_LENGTH (code); ++i)
> if (fmt[i] == 'e' || fmt[i] == 'u')
> - swap_const_vector_halves (XEXP (op, i));
> + swap_const_vector_halves (&XEXP (op, i));
> else if (fmt[i] == 'E')
> for (j = 0; j < XVECLEN (op, i); ++j)
> - swap_const_vector_halves (XVECEXP (op, i, j));
> + swap_const_vector_halves (&XVECEXP (op, i, j));
> }
> }
>
> @@ -42900,8 +42902,7 @@ handle_special_swappables (swap_web_entr
> {
> /* A CONST_VECTOR will only show up somewhere in the RHS of a SET. */
> gcc_assert (GET_CODE (body) == SET);
> - rtx rhs = SET_SRC (body);
> - swap_const_vector_halves (rhs);
> + swap_const_vector_halves (&SET_SRC (body));
> if (dump_file)
> fprintf (dump_file, "Swapping constant halves in insn %d\n", i);
> break;
> Index: gcc/config/rs6000/rs6000-p8swap.c
> ===================================================================
> --- gcc/config/rs6000/rs6000-p8swap.c 2017-12-28 16:57:58.744157771 +0000
> +++ gcc/config/rs6000/rs6000-p8swap.c 2017-12-28 16:58:43.017987848 +0000
> @@ -36,6 +36,7 @@ #define IN_TARGET_CODE 1
> #include "expr.h"
> #include "output.h"
> #include "tree-pass.h"
> +#include "rtx-vector-builder.h"
>
> /* Analyze vector computations and remove unnecessary doubleword
> swaps (xxswapdi instructions). This pass is performed only
> @@ -931,23 +932,24 @@ mark_swaps_for_removal (swap_web_entry *
> }
> }
>
> -/* OP is either a CONST_VECTOR or an expression containing one.
> +/* *OP_PTR is either a CONST_VECTOR or an expression containing one.
> Swap the first half of the vector with the second in the first
> case. Recurse to find it in the second. */
> static void
> -swap_const_vector_halves (rtx op)
> +swap_const_vector_halves (rtx *op_ptr)
> {
> int i;
> + rtx op = *op_ptr;
> enum rtx_code code = GET_CODE (op);
> if (GET_CODE (op) == CONST_VECTOR)
> {
> - int half_units = GET_MODE_NUNITS (GET_MODE (op)) / 2;
> - for (i = 0; i < half_units; ++i)
> - {
> - rtx temp = CONST_VECTOR_ELT (op, i);
> - CONST_VECTOR_ELT (op, i) = CONST_VECTOR_ELT (op, i + half_units);
> - CONST_VECTOR_ELT (op, i + half_units) = temp;
> - }
> + int units = GET_MODE_NUNITS (GET_MODE (op));
> + rtx_vector_builder builder (GET_MODE (op), units, 1);
> + for (i = 0; i < units / 2; ++i)
> + builder.quick_push (CONST_VECTOR_ELT (op, i + units / 2));
> + for (i = 0; i < units / 2; ++i)
> + builder.quick_push (CONST_VECTOR_ELT (op, i));
> + *op_ptr = builder.build ();
> }
> else
> {
> @@ -955,10 +957,10 @@ swap_const_vector_halves (rtx op)
> const char *fmt = GET_RTX_FORMAT (code);
> for (i = 0; i < GET_RTX_LENGTH (code); ++i)
> if (fmt[i] == 'e' || fmt[i] == 'u')
> - swap_const_vector_halves (XEXP (op, i));
> + swap_const_vector_halves (&XEXP (op, i));
> else if (fmt[i] == 'E')
> for (j = 0; j < XVECLEN (op, i); ++j)
> - swap_const_vector_halves (XVECEXP (op, i, j));
> + swap_const_vector_halves (&XVECEXP (op, i, j));
> }
> }
>
> @@ -1251,8 +1253,7 @@ handle_special_swappables (swap_web_entr
> {
> /* A CONST_VECTOR will only show up somewhere in the RHS of a SET. */
> gcc_assert (GET_CODE (body) == SET);
> - rtx rhs = SET_SRC (body);
> - swap_const_vector_halves (rhs);
> + swap_const_vector_halves (&SET_SRC (body));
> if (dump_file)
> fprintf (dump_file, "Swapping constant halves in insn %d\n", i);
> break;
