[PATCH 0/7] delete double assignment

[PATCH 0/7] delete double assignment

[Julia Lawall]

These patches fix cases where there are two adjacent assignments to the
same location.  In practice, many such occurrences appear to be
intentional, eg to initialize volatile memory, but these cases do not seem
to fall into that category.

The complete semantic match that finds these problems is as follows:

// <smpl>
@r@
expression i,f;
position p1,p2;
@@

(
 i = <+...f(...)...+>;
|
 i |= <+...f(...)...+>;
|
 i &= <+...f(...)...+>;
|
 i += <+...f(...)...+>;
|
 i -= <+...f(...)...+>;
|
 i *= <+...f(...)...+>;
|
 i /= <+...f(...)...+>;
|
 i %= <+...f(...)...+>;
|
 i ^= <+...f(...)...+>;
|
 i <<= <+...f(...)...+>;
|
 i >>= <+...f(...)...+>;
|
 i@p1 = ...;
|
 i@p1 |= ...;
|
 i@p1 &= ...;
|
 i@p1 += ...;
|
 i@p1 -= ...;
|
 i@p1 *= ...;
|
 i@p1 /= ...;
|
 i@p1 %= ...;
|
 i@p1 ^= ...;
|
 i@p1 <<= ...;
|
 i@p1 >>= ...;
|
 i@p1 ++;
|
 ++i@p1;
|
 i@p1 --;
|
 --i@p1;
)
(
 i = <+...i...+>;
|
 i = <+...f(...)...+>;
|
 i@p2 = ...;
)

@@
expression i,j,f;
position r.p1,r.p2;
@@

(
 (<+...i@p1...+>);
)
(
 (<+...\(j++\|++j\|j--\|--j\|f(...)\)...+>) = ...;
|
*i@p2 = ...;
)
// </smpl>

[PATCH 4/7] MIPS: BCM63xx: delete double assignment

[Julia Lawall]

From: Julia Lawall <Julia.Lawall@lip6.fr>

Delete successive assignments to the same location.  In each case, the
duplicated assignment is modified to be in line with other nearby code.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression i;
@@

*i = ...;
 i = ...;
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
The patches in this series do not depend on each other.

Not compiled.  This patch changes the semantics of the code.

 arch/mips/bcm63xx/irq.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/bcm63xx/irq.c b/arch/mips/bcm63xx/irq.c
index 37eb2d1..b94bf44 100644
--- a/arch/mips/bcm63xx/irq.c
+++ b/arch/mips/bcm63xx/irq.c
@@ -434,7 +434,7 @@ static void bcm63xx_init_irq(void)
 		irq_stat_addr[0] += PERF_IRQSTAT_3368_REG;
 		irq_mask_addr[0] += PERF_IRQMASK_3368_REG;
 		irq_stat_addr[1] = 0;
-		irq_stat_addr[1] = 0;
+		irq_mask_addr[1] = 0;
 		irq_bits = 32;
 		ext_irq_count = 4;
 		ext_irq_cfg_reg1 = PERF_EXTIRQ_CFG_REG_3368;
@@ -443,7 +443,7 @@ static void bcm63xx_init_irq(void)
 		irq_stat_addr[0] += PERF_IRQSTAT_6328_REG(0);
 		irq_mask_addr[0] += PERF_IRQMASK_6328_REG(0);
 		irq_stat_addr[1] += PERF_IRQSTAT_6328_REG(1);
-		irq_stat_addr[1] += PERF_IRQMASK_6328_REG(1);
+		irq_mask_addr[1] += PERF_IRQMASK_6328_REG(1);
 		irq_bits = 64;
 		ext_irq_count = 4;
 		is_ext_irq_cascaded = 1;

Re: [PATCH 4/7] MIPS: BCM63xx: delete double assignment

[Ralf Baechle]

On Sat, Aug 23, 2014 at 08:33:25PM +0200, Julia Lawall wrote:

> Delete successive assignments to the same location.  In each case, the
> duplicated assignment is modified to be in line with other nearby code.
> 
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)

Looking good, applied.

Thanks,

  Ralf

Re: [PATCH 4/7] MIPS: BCM63xx: delete double assignment

[Jonas Gorski]

On Mon, Aug 25, 2014 at 1:27 PM, Ralf Baechle <ralf@linux-mips.org> wrote:
> On Sat, Aug 23, 2014 at 08:33:25PM +0200, Julia Lawall wrote:
>
>> Delete successive assignments to the same location.  In each case, the
>> duplicated assignment is modified to be in line with other nearby code.
>>
>> A simplified version of the semantic match that finds this problem is as
>> follows: (http://coccinelle.lip6.fr/)
>
> Looking good, applied.

Huh, somehow gmail decided the original emails were spam.

> Thanks,
>
>   Ralf

Also thanks from me for cleaning up behind me! These mistakes were
definitely mine.


Jonas