[01/13] Add a qimode_for_vec_perm helper function

Message ID 87efo3mrds.fsf@linaro.org
State New
Headers show
Series
  • Make VEC_PERM_EXPR work for variable-length vectors
Related show

Commit Message

Richard Sandiford Dec. 9, 2017, 11:08 p.m.
The vec_perm code falls back to doing byte-level permutes if
element-level permutes aren't supported.  There were two copies
of the code to calculate the mode, and later patches add another,
so this patch splits it out into a helper function.


2017-12-09  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* optabs-query.h (qimode_for_vec_perm): Declare.
	* optabs-query.c (can_vec_perm_p): Split out qimode search to...
	(qimode_for_vec_perm): ...this new function.
	* optabs.c (expand_vec_perm): Use qimode_for_vec_perm.

Comments

Richard Biener Dec. 18, 2017, 1:34 p.m. | #1
On Sun, Dec 10, 2017 at 12:08 AM, Richard Sandiford
<richard.sandiford@linaro.org> wrote:
> The vec_perm code falls back to doing byte-level permutes if

> element-level permutes aren't supported.  There were two copies

> of the code to calculate the mode, and later patches add another,

> so this patch splits it out into a helper function.

>


Ok.

> 2017-12-09  Richard Sandiford  <richard.sandiford@linaro.org>

>

> gcc/

>         * optabs-query.h (qimode_for_vec_perm): Declare.

>         * optabs-query.c (can_vec_perm_p): Split out qimode search to...

>         (qimode_for_vec_perm): ...this new function.

>         * optabs.c (expand_vec_perm): Use qimode_for_vec_perm.

>

> Index: gcc/optabs-query.h

> ===================================================================

> --- gcc/optabs-query.h  2017-12-09 22:47:12.476364764 +0000

> +++ gcc/optabs-query.h  2017-12-09 22:47:14.730310076 +0000

> @@ -174,6 +174,7 @@ enum insn_code can_extend_p (machine_mod

>  enum insn_code can_float_p (machine_mode, machine_mode, int);

>  enum insn_code can_fix_p (machine_mode, machine_mode, int, bool *);

>  bool can_conditionally_move_p (machine_mode mode);

> +opt_machine_mode qimode_for_vec_perm (machine_mode);

>  bool can_vec_perm_p (machine_mode, bool, vec_perm_indices *);

>  /* Find a widening optab even if it doesn't widen as much as we want.  */

>  #define find_widening_optab_handler(A, B, C) \

> Index: gcc/optabs-query.c

> ===================================================================

> --- gcc/optabs-query.c  2017-12-09 22:47:12.476364764 +0000

> +++ gcc/optabs-query.c  2017-12-09 22:47:14.729310075 +0000

> @@ -345,6 +345,22 @@ can_conditionally_move_p (machine_mode m

>    return direct_optab_handler (movcc_optab, mode) != CODE_FOR_nothing;

>  }

>

> +/* If a target doesn't implement a permute on a vector with multibyte

> +   elements, we can try to do the same permute on byte elements.

> +   If this makes sense for vector mode MODE then return the appropriate

> +   byte vector mode.  */

> +

> +opt_machine_mode

> +qimode_for_vec_perm (machine_mode mode)

> +{

> +  machine_mode qimode;

> +  if (GET_MODE_INNER (mode) != QImode

> +      && mode_for_vector (QImode, GET_MODE_SIZE (mode)).exists (&qimode)

> +      && VECTOR_MODE_P (qimode))

> +    return qimode;

> +  return opt_machine_mode ();

> +}

> +

>  /* Return true if VEC_PERM_EXPR of arbitrary input vectors can be

>     expanded using SIMD extensions of the CPU.  SEL may be NULL, which

>     stands for an unknown constant.  Note that additional permutations

> @@ -375,9 +391,7 @@ can_vec_perm_p (machine_mode mode, bool

>      return true;

>

>    /* We allow fallback to a QI vector mode, and adjust the mask.  */

> -  if (GET_MODE_INNER (mode) == QImode

> -      || !mode_for_vector (QImode, GET_MODE_SIZE (mode)).exists (&qimode)

> -      || !VECTOR_MODE_P (qimode))

> +  if (!qimode_for_vec_perm (mode).exists (&qimode))

>      return false;

>

>    /* ??? For completeness, we ought to check the QImode version of

> Index: gcc/optabs.c

> ===================================================================

> --- gcc/optabs.c        2017-12-09 22:47:12.476364764 +0000

> +++ gcc/optabs.c        2017-12-09 22:47:14.731310077 +0000

> @@ -5452,9 +5452,7 @@ expand_vec_perm (machine_mode mode, rtx

>

>    /* Set QIMODE to a different vector mode with byte elements.

>       If no such mode, or if MODE already has byte elements, use VOIDmode.  */

> -  if (GET_MODE_INNER (mode) == QImode

> -      || !mode_for_vector (QImode, w).exists (&qimode)

> -      || !VECTOR_MODE_P (qimode))

> +  if (!qimode_for_vec_perm (mode).exists (&qimode))

>      qimode = VOIDmode;

>

>    /* If the input is a constant, expand it specially.  */

Patch

Index: gcc/optabs-query.h
===================================================================
--- gcc/optabs-query.h	2017-12-09 22:47:12.476364764 +0000
+++ gcc/optabs-query.h	2017-12-09 22:47:14.730310076 +0000
@@ -174,6 +174,7 @@  enum insn_code can_extend_p (machine_mod
 enum insn_code can_float_p (machine_mode, machine_mode, int);
 enum insn_code can_fix_p (machine_mode, machine_mode, int, bool *);
 bool can_conditionally_move_p (machine_mode mode);
+opt_machine_mode qimode_for_vec_perm (machine_mode);
 bool can_vec_perm_p (machine_mode, bool, vec_perm_indices *);
 /* Find a widening optab even if it doesn't widen as much as we want.  */
 #define find_widening_optab_handler(A, B, C) \
Index: gcc/optabs-query.c
===================================================================
--- gcc/optabs-query.c	2017-12-09 22:47:12.476364764 +0000
+++ gcc/optabs-query.c	2017-12-09 22:47:14.729310075 +0000
@@ -345,6 +345,22 @@  can_conditionally_move_p (machine_mode m
   return direct_optab_handler (movcc_optab, mode) != CODE_FOR_nothing;
 }
 
+/* If a target doesn't implement a permute on a vector with multibyte
+   elements, we can try to do the same permute on byte elements.
+   If this makes sense for vector mode MODE then return the appropriate
+   byte vector mode.  */
+
+opt_machine_mode
+qimode_for_vec_perm (machine_mode mode)
+{
+  machine_mode qimode;
+  if (GET_MODE_INNER (mode) != QImode
+      && mode_for_vector (QImode, GET_MODE_SIZE (mode)).exists (&qimode)
+      && VECTOR_MODE_P (qimode))
+    return qimode;
+  return opt_machine_mode ();
+}
+
 /* Return true if VEC_PERM_EXPR of arbitrary input vectors can be
    expanded using SIMD extensions of the CPU.  SEL may be NULL, which
    stands for an unknown constant.  Note that additional permutations
@@ -375,9 +391,7 @@  can_vec_perm_p (machine_mode mode, bool
     return true;
 
   /* We allow fallback to a QI vector mode, and adjust the mask.  */
-  if (GET_MODE_INNER (mode) == QImode
-      || !mode_for_vector (QImode, GET_MODE_SIZE (mode)).exists (&qimode)
-      || !VECTOR_MODE_P (qimode))
+  if (!qimode_for_vec_perm (mode).exists (&qimode))
     return false;
 
   /* ??? For completeness, we ought to check the QImode version of
Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c	2017-12-09 22:47:12.476364764 +0000
+++ gcc/optabs.c	2017-12-09 22:47:14.731310077 +0000
@@ -5452,9 +5452,7 @@  expand_vec_perm (machine_mode mode, rtx
 
   /* Set QIMODE to a different vector mode with byte elements.
      If no such mode, or if MODE already has byte elements, use VOIDmode.  */
-  if (GET_MODE_INNER (mode) == QImode
-      || !mode_for_vector (QImode, w).exists (&qimode)
-      || !VECTOR_MODE_P (qimode))
+  if (!qimode_for_vec_perm (mode).exists (&qimode))
     qimode = VOIDmode;
 
   /* If the input is a constant, expand it specially.  */