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[Bug middle-end/30904] New: [dataflow] No longer optimizes shifts with large count
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 21 Feb 2007 09:53:50 -0000
- Subject: [Bug middle-end/30904] New: [dataflow] No longer optimizes shifts with large count
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
extern void link_error (const char *);
extern int ones;
void foo(int);
void kernel ()
{
struct { unsigned int a : 7; } s;
s.a = ones;
if (s.a >> 8)
link_error ("foo");
if (s.a >> 9)
link_error ("foo");
}
mainline optimizes this to an empty function with -O2, dataflow branch
retains the s.a >> 9 check.
--
Summary: [dataflow] No longer optimizes shifts with large count
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30904