Broken arguments access
Starting February 13th, gfrotran fails on the following test case on
ia32/ia64/x86_64 platforms with all kinds of optimizations: -O0, -O1, -O2 etc.
The issue is critical because it affects SPEC cpu2k tests wupwise and galgel on
all platforms.
$ cat foo.f
program foo
character*1 a1, a2, b
a1='A'
a2='A'
b='B'
x = LSAME(a1,a2)
if ( x.eq.1 ) then
write(*,*) 'passsed'
else
write(*,*) 'failed'
endif
end
logical function LSAME( CA, CB )
character CA, CB
integer INTA, INTB
INTA = ICHAR( CA )
INTB = ICHAR( CB )
write(*,*) INTA, INTB
LSAME = INTA.EQ.INTB
end
The reason of failure is the broken argument access for the function. Here is
the ia32 Linux code obtained with -O0 optimization.
.type lsame_, @function
lsame_:
pushl %ebp
movl %esp, %ebp
subl $16, %esp
movl 8(%ebp), %eax
movb -1(%eax), %al <-- Wrong. Must be "movb (%eax), %al"
movzbl %al, %eax
movl %eax, -8(%ebp)
movl 12(%ebp), %eax
movb -1(%eax), %al <-- Wrong. Must be "movb (%eax), %al"
movzbl %al, %eax
This issue has been discussed here http://gcc.gnu.org/ml/gcc/2005-
02/msg00685.html but not resolved yet and bug search gave me nothing. It
appears that breakage introduced by revision 2.110 (and later 2.112) of
gcc/gimplify.c. The exact place is:
$ cvs diff -r 2.111 -r 2.112
gcc/gimplify.c
3797a3799,3803
> case INDIRECT_REF:
> *expr_p = fold_indirect_ref (*expr_p);
> if (*expr_p != save_expr)
> break;
> /* else fall through. */
3800d3805
< case INDIRECT_REF:
--
Summary: Broken arguments access
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: grigory dot zagorodnev at intel dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC host triplet: i686-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20030
