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Fix volatile issues in optimize_bit_field_compare.

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2013-10-21  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        Fix volatile issues in optimize_bit_field_compare.
        * fold-const.c (optimize_bit_field_compare): Bail out if
        lvolatilep or rvolatilep.

From-SVN: r203899
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Bernd Edlinger 2013-10-21 15:57:05 +00:00 • committed by Bernd Edlinger
parent 5dfd32cdda
commit 0cad6830a4
2 changed files with 13 additions and 22 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2013-10-21 Bernd Edlinger <bernd.edlinger@hotmail.de>
Fix volatile issues in optimize_bit_field_compare.
* fold-const.c (optimize_bit_field_compare): Bail out if
lvolatilep or rvolatilep.
2013-10-21 Bernd Edlinger <bernd.edlinger@hotmail.de>
Fix DECL_BIT_FIELD depencency on flag_strict_volatile_bitfields

29
gcc/fold-const.c
View file

@ -3473,11 +3473,6 @@ optimize_bit_field_compare (location_t loc, enum tree_code code,
tree mask;
tree offset;
/* In the strict volatile bitfields case, doing code changes here may prevent
other optimizations, in particular in a SLOW_BYTE_ACCESS setting. */
if (flag_strict_volatile_bitfields > 0)
return 0;
/* Get all the information about the extractions being done. If the bit size
if the same as the size of the underlying object, we aren't doing an
extraction at all and so can do nothing. We also don't want to
@ -3486,7 +3481,7 @@ optimize_bit_field_compare (location_t loc, enum tree_code code,
linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
&lunsignedp, &lvolatilep, false);
if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
|| offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR)
|| offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR || lvolatilep)
return 0;
if (!const_p)
@ -3498,22 +3493,17 @@ optimize_bit_field_compare (location_t loc, enum tree_code code,
if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
|| lunsignedp != runsignedp || offset != 0
|| TREE_CODE (rinner) == PLACEHOLDER_EXPR)
|| TREE_CODE (rinner) == PLACEHOLDER_EXPR || rvolatilep)
return 0;
}
/* See if we can find a mode to refer to this field. We should be able to,
but fail if we can't. */
if (lvolatilep
&& GET_MODE_BITSIZE (lmode) > 0
&& flag_strict_volatile_bitfields > 0)
nmode = lmode;
else
nmode = get_best_mode (lbitsize, lbitpos, 0, 0,
const_p ? TYPE_ALIGN (TREE_TYPE (linner))
: MIN (TYPE_ALIGN (TREE_TYPE (linner)),
TYPE_ALIGN (TREE_TYPE (rinner))),
word_mode, lvolatilep || rvolatilep);
nmode = get_best_mode (lbitsize, lbitpos, 0, 0,
const_p ? TYPE_ALIGN (TREE_TYPE (linner))
: MIN (TYPE_ALIGN (TREE_TYPE (linner)),
TYPE_ALIGN (TREE_TYPE (rinner))),
word_mode, false);
if (nmode == VOIDmode)
return 0;
@ -3602,11 +3592,6 @@ optimize_bit_field_compare (location_t loc, enum tree_code code,
appropriate number of bits and mask it with the computed mask
(in case this was a signed field). If we changed it, make a new one. */
lhs = make_bit_field_ref (loc, linner, unsigned_type, nbitsize, nbitpos, 1);
if (lvolatilep)
{
TREE_SIDE_EFFECTS (lhs) = 1;
TREE_THIS_VOLATILE (lhs) = 1;
}
rhs = const_binop (BIT_AND_EXPR,
const_binop (LSHIFT_EXPR,