[forwarded from https://launchpad.net/bugs/590859]
seen with 4.4 branch and -O2, not -O1, works with 4.3.
When compiling with :
gcc -O2 -c -o proc.o proc.c
The generated code is :
0x000000af <+175>: movl $0x0,%gs:0x4
0x000000ba <+186>: lgdtl (%edx)
0x000000bd <+189>: mov $0x18,%edx
0x000000c2 <+194>: mov %edx,%gs
0x000000c4 <+196>: mov %eax,%gs:0x0
When compiling with :
gcc -O1 -c -o proc.o proc.c
0x000000af <+175>: lgdtl (%edx)
0x000000b2 <+178>: mov $0x18,%edx
0x000000b7 <+183>: mov %edx,%gs
0x000000b9 <+185>: mov %eax,%gs:0x0
0x000000bf <+191>: movl $0x0,%gs:0x4
The first code is wrong : register GS is used (movl $0x0,%gs:0x4) before
loading the GDT (lgdtl (%edx))
--
Summary: [4.4 regression] wrong code (wrong order) generated with
-O2
Product: gcc
Version: 4.4.4
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: doko at ubuntu dot com
GCC target triplet: i486-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44624
