Hi. I need your help again. I wrote my own backend for the gcc-4.6.2
and with your help it works nearly perfectly.
But i have a problem with the test case pr26180.c. The compiler does
not load the register, which
is used for the comparison. And i don't get why.
C-Code:
...
x2 = (x > 0 ? x : (-x));
...
Wrong translated assembler code:
...
;;x > 0 ?
cmpi.l r8,-2147483648 <- r8 is not used in the entire function
and so it is not initialized with x.
jmp C,_L2
;;x2 = x
xori.l r8,-1
addi.l r8,1
_L2:
;;x2 = -x
...
If i only change the comparison integer from 0 to 1 the translation
works correct:
C-Code:
...
x2 = (x > 1 ? x : (-x));
...
Correct translated assembler code:
...
;;load r8
mov.l r8,fp
addi.l r8,4
mov.l r9,r8
ldr.l r8,r9
;;x > 1 ?
cmpi.l r8,1
sbs Z
jmpn N,_L2
;;x2 = -x
mov.l r8,fp
addi.l r8,4
mov.l r9,r8
ldr.l r8,r9
xori.l r8,-1
addi.l r8,1
jmp T,_L3
_L2:
;;x2 = x
mov.l r8,fp
addi.l r8,4
mov.l r9,r8
ldr.l r8,r9
_L3:
...
The translation works also correctly if i use "if else" instead of "?:".
So i you would like to ask you, which pattern is related to "x2 = (x >
0 ? x : (-x));"
or where i should search for this problem.
Thanks in advance.
Best regards,
Andreas
