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From: "anton at samba dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/21017] New: ppc 64bit target not using rlwinm Date: Thu, 14 Apr 2005 01:39:00 -0000 [thread overview] Message-ID: <20050414013914.21017.anton@samba.org> (raw) Using a recent 4.0 CVS: gcc version 4.0.0 20050412 (prerelease) Compiling the following as 64bit: unsigned int foo(unsigned int x) { return ((x >> 16) & 0xffff) | ((x & 0xffff) << 16); } Results in: .L.foo: slwi 0,3,16 srwi 3,3,16 or 3,3,0 rldicl 3,3,0,32 blr Compiling for 32bit results in: foo: rlwinm 3,3,16,0xffffffff blr It looks like the 64bit case could be done in 2 instructions if we masked the top 32bits of the rlwinm result. -- Summary: ppc 64bit target not using rlwinm Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: enhancement Priority: P2 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: anton at samba dot org CC: gcc-bugs at gcc dot gnu dot org GCC target triplet: powerpc64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21017
next reply other threads:[~2005-04-14 1:39 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2005-04-14 1:39 anton at samba dot org [this message] 2005-04-14 14:13 ` [Bug target/21017] " pinskia at gcc dot gnu dot org 2005-04-14 16:26 ` pinskia at gcc dot gnu dot org 2005-04-14 19:41 ` pinskia at gcc dot gnu dot org 2005-09-06 0:28 ` amodra at bigpond dot net dot au 2005-09-06 0:37 ` amodra at bigpond dot net dot au 2005-09-06 1:36 ` amodra at bigpond dot net dot au
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