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[Bug c/35762] New: wrong code emitted for loop with volatile induction variable
- From: "regehr at cs dot utah dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Mar 2008 03:39:46 -0000
- Subject: [Bug c/35762] New: wrong code emitted for loop with volatile induction variable
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
This is for "gcc version 4.3.0 (GCC)"
This is similar to bug 35729. I'm filing a new report since the behavior seems
to be a different one.
This code:
volatile short g_10 = 0;
volatile int g_13 = 0;
int func_1 (void)
{
for (g_10 = 0; g_10 > 10; g_10++)
return g_13;
return 0;
}
When compiled with:
gcc -O1 -S foo.c
gives:
func_1:
pushl %ebp
movl %esp, %ebp
movw $0, g_10
movzwl g_10, %eax
cmpw $10, %ax
setle %al
movzbl %al, %eax
subl $1, %eax
andl g_13, %eax
popl %ebp
ret
The output is not correct, it unconditionally returns the value from g_13.
--
Summary: wrong code emitted for loop with volatile induction
variable
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: regehr at cs dot utah dot edu
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35762