https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61923
Bug ID: 61923
Summary: [4.8/4.9/4.10 Regression] -fcompare-debug errors while
building Linux kernel.
Product: gcc
Version: 4.8.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: trippels at gcc dot gnu.org
Building the Linux kernel with "GCC_COMPARE_DEBUG=1 make" hits several
failures.
markus@x4 tmp % cat inode.i
typedef struct
{
struct
{
struct
{
char head;
} tickets;
};
} arch_spinlock_t;
struct ext4_map_blocks
{
int m_lblk;
int m_len;
int m_flags;
};
int ext4_da_map_blocks_ei_0;
void fn1 (int p1, struct ext4_map_blocks *p2)
{
int ret;
if (p2->m_flags)
{
ext4_da_map_blocks_ei_0++;
arch_spinlock_t *lock;
switch (sizeof *&lock->tickets.head)
case 1:
asm("" : "+m"(*&lock->tickets.head) : ""(0));
__asm__("");
ret = 0;
}
fn2 (p2->m_lblk, p2->m_len);
}
markus@x4 tmp % gcc -c -O2 -fcompare-debug inode.i --save-temps
gcc: error: inode.i: -fcompare-debug failure (length)
markus@x4 tmp % diff -u inode.gkd inode.gk.gkd
--- inode.gkd 2014-07-26 22:01:20.578062879 +0200
+++ inode.gk.gkd 2014-07-26 22:01:20.598062450 +0200
@@ -82,7 +82,7 @@
(expr_list:REG_EQUIV (mem:SI (plus:DI (reg/v/f:DI 0 ax [orig:90 p2 ]
[90])
(const_int 4 [0x4])) [ p2_3(D)->m_len+0 S4 A32])
(nil)))
-(insn:TI# 0 0 4 (set (reg:SI 5 di)
+(insn# 0 0 4 (set (reg:SI 5 di)
(mem:SI (reg/v/f:DI 0 ax [orig:90 p2 ] [90]) [ p2_3(D)->m_lblk+0 S4
A32])) inode.i:31# {*movsi_internal}
(expr_list:REG_DEAD (reg/v/f:DI 0 ax [orig:90 p2 ] [90])
(nil)))
