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* [Bug middle-end/52919] New: shift expansion mishandles SHIFT_COUNT_TRUNCATED on partial integer modes
@ 2012-04-09 22:27 bigotp at acm dot org
  2012-04-09 22:30 ` [Bug middle-end/52919] " bigotp at acm dot org
  0 siblings, 1 reply; 2+ messages in thread
From: bigotp at acm dot org @ 2012-04-09 22:27 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52919

             Bug #: 52919
           Summary: shift expansion mishandles SHIFT_COUNT_TRUNCATED on
                    partial integer modes
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bigotp@acm.org


The code for SHIFT_COUNT_TRUNCATED in expmed.c:expand_shift_1 improperly uses
GET_MODE_BITSIZE instead of GET_MODE_PRECISION when calculating the truncation
value.  This can result in failure to identify an acceptable shift operation;
e.g. with a PSImode with 20 bits of precision, a shift of 20 may be requested.


^ permalink raw reply	[flat|nested] 2+ messages in thread
* [Bug middle-end/52919] shift expansion mishandles SHIFT_COUNT_TRUNCATED on partial integer modes
  2012-04-09 22:27 [Bug middle-end/52919] New: shift expansion mishandles SHIFT_COUNT_TRUNCATED on partial integer modes bigotp at acm dot org
@ 2012-04-09 22:30 ` bigotp at acm dot org
  0 siblings, 0 replies; 2+ messages in thread
From: bigotp at acm dot org @ 2012-04-09 22:30 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52919

--- Comment #1 from Peter A. Bigot <bigotp at acm dot org> 2012-04-09 22:30:20 UTC ---
Created attachment 27119
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27119
Replace GET_MODE_BITSIZE with GET_MODE_PRECISION where necessary


^ permalink raw reply	[flat|nested] 2+ messages in thread
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2012-04-09 22:27 [Bug middle-end/52919] New: shift expansion mishandles SHIFT_COUNT_TRUNCATED on partial integer modes bigotp at acm dot org
2012-04-09 22:30 ` [Bug middle-end/52919] " bigotp at acm dot org

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