Re: [096/nnn] poly_int: reloading complex subregs

[Jeff Law]

On 10/23/2017 11:39 AM, Richard Sandiford wrote:
> This patch splits out a condition that is common to both push_reload
> and reload_inner_reg_of_subreg.
> 
> 
> 2017-10-23  Richard Sandiford  
>   Alan Hayward  
>   David Sherwood  
> 
> gcc/
>   * reload.c (complex_word_subreg_p): New function.
>   (reload_inner_reg_of_subreg, push_reload): Use it.
OK.
jeff

[096/nnn] poly_int: reloading complex subregs

[Richard Sandiford]

This patch splits out a condition that is common to both push_reload
and reload_inner_reg_of_subreg.


2017-10-23  Richard Sandiford  
Alan Hayward  
David Sherwood  

gcc/
* reload.c (complex_word_subreg_p): New function.
(reload_inner_reg_of_subreg, push_reload): Use it.

Index: gcc/reload.c
===
--- gcc/reload.c2017-10-23 17:18:51.485721234 +0100
+++ gcc/reload.c2017-10-23 17:25:43.543674491 +0100
@@ -811,6 +811,23 @@ find_reusable_reload (rtx *p_in, rtx out
   return n_reloads;
 }
 
+/* Return true if:
+
+   (a) (subreg:OUTER_MODE REG ...) represents a word or subword subreg
+   of a multiword value; and
+
+   (b) the number of *words* in REG does not match the number of *registers*
+   in REG.  */
+
+static bool
+complex_word_subreg_p (machine_mode outer_mode, rtx reg)
+{
+  machine_mode inner_mode = GET_MODE (reg);
+  return (GET_MODE_SIZE (outer_mode) <= UNITS_PER_WORD
+ && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD
+ && GET_MODE_SIZE (inner_mode) / UNITS_PER_WORD != REG_NREGS (reg));
+}
+
 /* Return true if X is a SUBREG that will need reloading of its SUBREG_REG
expression.  MODE is the mode that X will be used in.  OUTPUT is true if
the function is invoked for the output part of an enclosing reload.  */
@@ -842,11 +859,7 @@ reload_inner_reg_of_subreg (rtx x, machi
  INNER is larger than a word and the number of registers in INNER is
  not the same as the number of words in INNER, then INNER will need
  reloading (with an in-out reload).  */
-  return (output
- && GET_MODE_SIZE (mode) <= UNITS_PER_WORD
- && GET_MODE_SIZE (GET_MODE (inner)) > UNITS_PER_WORD
- && ((GET_MODE_SIZE (GET_MODE (inner)) / UNITS_PER_WORD)
- != REG_NREGS (inner)));
+  return output && complex_word_subreg_p (mode, inner);
 }
 
 /* Return nonzero if IN can be reloaded into REGNO with mode MODE without
@@ -1064,12 +1077,7 @@ push_reload (rtx in, rtx out, rtx *inloc
  /* The case where out is nonzero
 is handled differently in the following statement.  */
  && (out == 0 || subreg_lowpart_p (in))
- && ((GET_MODE_SIZE (inmode) <= UNITS_PER_WORD
-  && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (in)))
-  > UNITS_PER_WORD)
-  && ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (in)))
-   / UNITS_PER_WORD)
-  != REG_NREGS (SUBREG_REG (in
+ && (complex_word_subreg_p (inmode, SUBREG_REG (in))
  || !targetm.hard_regno_mode_ok (subreg_regno (in), inmode)))
  || (secondary_reload_class (1, rclass, inmode, in) != NO_REGS
  && (secondary_reload_class (1, rclass, GET_MODE (SUBREG_REG (in)),