Hi!
Maybe this bug can interest you: when using byte swaping in le16_to_cpu
for example, mips gcc 2.95.2 and 2.91.66 sometime do not generate correct
code : the u16 to u32 convertion is missing. I found this bug while
compiling drivers/mtd/ftl.c in build_maps(). Here is a sample source to
reproduce the bug:
typedef unsigned short __u16;
extern __inline__ __const__ __u16 le16_to_cpu(__u16 x)
{
return ((__u16)( \
(((__u16)(x) & (__u16)0x00ffU) << 8) | \
(((__u16)(x) & (__u16)0xff00U) >> 8) ));
}
int test(int xtrans, int xvalid, __u16 *ptr)
{
if ((xvalid+xtrans != le16_to_cpu(*ptr))) {
return -1;
}
return 0;
}
The generated asm is :
test:
.frame $sp,0,$31 # vars= 0, regs= 0/0, args= 0,
extra= 0
.mask 0x00000000,0
.fmask 0x00000000,0
.set noreorder
.cpload $25
.set reorder
lhu $3,0($7)
addu $5,$6,$5
sll $4,$3,8
srl $3,$3,8
or $4,$4,$3
.set noreorder
.set nomacro
bne $5,$4,$L7
li $2,-1 # 0xffffffff
.set macro
.set reorder
move $2,$0
$L7:
j $31
.end test
The andi op is missing.
egcs-1.0.3 seems to be OK.
I have no experience in submitting gcc bugs, so if someone could forward
this mail to the relevant gcc mailing list...
Fabrice.
