Wrong code is generated causing bus error in test(gdb):
(gdb) r
Program received signal SIGBUS, Bus error.
0x00002b48 in bar ()
(gdb) disass
Dump of assembler code for function bar:
0x00002b40 <+0>: addil L%-800,dp,r1
0x00002b44 <+4>: ldo 780(r1),r1
=> 0x00002b48 <+8>: ldw 1(r1),ret0
0x00002b4c <+12>: extrw,u ret0,15,16,r19
0x00002b50 <+16>: sth r19,2(r1)
0x00002b54 <+20>: sth ret0,4(r1)
0x00002b58 <+24>: ldi 2e,ret0
0x00002b5c <+28>: bv r0(rp)
0x00002b60 <+32>: stb ret0,1(r1)
Register r1 points to str which has 4-byte alignment. So,
the memory address for the ldw instruction is misaligned.
The test would also fail on linux if the unaligned handler
was disabled.
We have the following for function bar after coalescing:
bar ()
{
unsigned int D.1980;
# BLOCK 2 freq:10000
# PRED: ENTRY [100.0%] (fallthru,exec)
D.1980_3 = MEM[(char * {ref-all})&str + 1B];
MEM[(char * {ref-all})&str + 2B] = D.1980_3;
str[1] = 46;
return;
# SUCC: EXIT [100.0%]
}
--
Summary: FAIL: gcc.dg/pr35258.c execution test
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: danglin at gcc dot gnu dot org
GCC build triplet: hppa*-*-hpux*
GCC host triplet: hppa*-*-hpux*
GCC target triplet: hppa*-*-hpux*
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44903
