On Thu, Mar 1, 2018 at 1:52 PM, Dibyendu Majumdar
<mobile@xxxxxxxxxxxxxxx> wrote:
> On 1 March 2018 at 20:57, Dibyendu Majumdar <mobile@xxxxxxxxxxxxxxx> wrote:
>> On 27 February 2018 at 01:12, Luc Van Oostenryck
>> <luc.vanoostenryck@xxxxxxxxx> wrote:
>>> On Mon, Feb 26, 2018 at 03:36:38PM -0800, Christopher Li wrote:
>>>>
>>>> You said you did not found crash in your first round testing.
>>>> However there is some regression of the IR. Can you share
>>>> the regression test case you found?
>>>
>>> I didn't spend much time at it but a typical small example
>>> of what I've seen is:
>>> void a(void) {
>>> long b;
>>> unsigned c = 0;
>>> for (;;)
>>> if (c)
>>> c = b;
>>> }
>>>
>>
>> Now where is the value pseudo of size 64 coming from as it is not in
>> the code above?
>>
>
> Okay it seems to come from flow.c in find_dominating_stores() - in the
> call to convert_load_instruction(). Any explanation of what this is
> doing?
That is just the memory operation convert to pseudo.
Sparse find out "b" has no dominating store (uninitialized), so
it just replace it with 0 value.
The 64 bit one is b, the long type.
The 32 bit one is c, the int type.
I already find out the place cause it:
The fix is here:
Chris
simplify cast of constant using wrong size
This fix the test case after the merge.
The constant pseudo need to use the target size.
Signed-off-by: Christopher Li <sparse@xxxxxxxxxxx>
diff --git a/simplify.c b/simplify.c
index 09931fe..3d32cdd 100644
--- a/simplify.c
+++ b/simplify.c
@@ -950,7 +950,7 @@ static int simplify_cast(struct instruction *insn)
if (constant(src)) {
int sign = orig_type->ctype.modifiers & MOD_SIGNED;
long long val = get_cast_value(src->value, orig_size,
size, sign);
- src = value_pseudo(orig_type, val);
+ src = value_pseudo(insn->type, val);
goto simplify;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-sparse" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
