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expr.c (expand_assignment): Fold the bitpos in the to_rtx if sufficiently aligned and an offset is used at...

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2014-05-28  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * expr.c (expand_assignment): Fold the bitpos in the to_rtx if
        sufficiently aligned and an offset is used at the same time.
        (expand_expr_real_1): Likewise.

From-SVN: r211020
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Bernd Edlinger 2014-05-28 13:37:02 +00:00 committed by Bernd Edlinger
parent b017a17489
commit 7fbf8a3ede
2 changed files with 31 additions and 12 deletions
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@ -1,3 +1,9 @@
2014-05-28 Bernd Edlinger <bernd.edlinger@hotmail.de>
* expr.c (expand_assignment): Fold the bitpos in the to_rtx if
sufficiently aligned and an offset is used at the same time.
(expand_expr_real_1): Likewise.
2014-05-28 Richard Biener <rguenther@suse.de>
PR middle-end/61045

37
gcc/expr.c
View File

@ -4838,15 +4838,29 @@ expand_assignment (tree to, tree from, bool nontemporal)
if (GET_MODE (offset_rtx) != address_mode)
offset_rtx = convert_to_mode (address_mode, offset_rtx, 0);
/* The check for a constant address in TO_RTX not having VOIDmode
is probably no longer necessary. */
if (MEM_P (to_rtx)
&& GET_MODE (to_rtx) == BLKmode
&& GET_MODE (XEXP (to_rtx, 0)) != VOIDmode
/* If we have an expression in OFFSET_RTX and a non-zero
byte offset in BITPOS, adding the byte offset before the
OFFSET_RTX results in better intermediate code, which makes
later rtl optimization passes perform better.
We prefer intermediate code like this:
r124:DI=r123:DI+0x18
[r124:DI]=r121:DI
... instead of ...
r124:DI=r123:DI+0x10
[r124:DI+0x8]=r121:DI
This is only done for aligned data values, as these can
be expected to result in single move instructions. */
if (mode1 != VOIDmode
&& bitpos != 0
&& bitsize > 0
&& (bitpos % bitsize) == 0
&& (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
&& MEM_ALIGN (to_rtx) == GET_MODE_ALIGNMENT (mode1))
&& MEM_ALIGN (to_rtx) >= GET_MODE_ALIGNMENT (mode1))
{
to_rtx = adjust_address (to_rtx, mode1, bitpos / BITS_PER_UNIT);
bitregion_start = 0;
@ -10090,14 +10104,13 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
if (GET_MODE (offset_rtx) != address_mode)
offset_rtx = convert_to_mode (address_mode, offset_rtx, 0);
if (GET_MODE (op0) == BLKmode
/* The check for a constant address in OP0 not having VOIDmode
is probably no longer necessary. */
&& GET_MODE (XEXP (op0, 0)) != VOIDmode
&& bitsize != 0
/* See the comment in expand_assignment for the rationale. */
if (mode1 != VOIDmode
&& bitpos != 0
&& bitsize > 0
&& (bitpos % bitsize) == 0
&& (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
&& MEM_ALIGN (op0) == GET_MODE_ALIGNMENT (mode1))
&& MEM_ALIGN (op0) >= GET_MODE_ALIGNMENT (mode1))
{
op0 = adjust_address (op0, mode1, bitpos / BITS_PER_UNIT);
bitpos = 0;