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[Bug other/16800] New: PowerPC - Unnecessary rldicl
- From: "gcc-bugzilla at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 28 Jul 2004 17:00:56 -0000
- Subject: [Bug other/16800] New: PowerPC - Unnecessary rldicl
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
Description:
A non-optimal code sequence is illustrated. The rldicl noted below is not needed (and doesn't occur for the "==" comparison). Duplicate using gcc 3.5 and command line:
gcc -O3 -m64 -c test.c
Testcase:
long l1,l2;
float f1,f2,f3,f4;
void logic_func4() {
l1 = (f1 == f2);
l2 = (f3 > f4);
}
Assembly:
.logic_func4:
ld 8,.LC5@toc(2)
ld 6,.LC4@toc(2)
lfs 13,0(8)
lfs 11,0(6)
ld 5,.LC1@toc(2)
ld 4,.LC2@toc(2)
lfs 12,0(5)
fcmpu 7,11,13
lfs 0,0(4)
ld 11,.LC0@toc(2)
ld 10,.LC3@toc(2)
fcmpu 6,12,0
mfcr 3
rlwinm 3,3,30,1
rldicl 0,3,0,32 <-- Unnecessary.
mfcr 9
rlwinm 9,9,27,1
std 0,0(10)
std 9,0(11)
blr
--
Summary: PowerPC - Unnecessary rldicl
Product: gcc
Version: 3.5.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P1
Component: other
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: steinmtz at us dot ibm dot com
CC: gcc-bugs at gcc dot gnu dot org,steinmtz at us dot ibm
dot com
GCC build triplet: powerpc64-linux
GCC host triplet: powerpc64-linux
GCC target triplet: powerpc64-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16800