Re: [PATCH] misplaced parenthesis?

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The wrong version of course produces different code....

the original and the corrected one may produce different code depending on how the compiler schedules things.

randolph

Matt Turner wrote:
Does gcc produce different code for the three variations?

Matt

On Sat, May 16, 2009 at 12:14 AM, Randolph Chung <randolph@xxxxxxxxx> wrote:
This is a bit confusingly written, but your patch does not appear to be
correct.

== has higher precedence than &, so you are basically changing it to:
if (likely(t1 & 1))

it really should be

-       if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
+       if (likely((t1 & (sizeof(unsigned int)-1)) == 0)) {

randolph


Roel Kluin wrote:
Fix misplaced parenthesis.

Signed-off-by: Roel Kluin <roel.kluin@xxxxxxxxx>
---
I think this is what was intended? Note that this patch may affect
profiling.

diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c
index bbda909..30207b0 100644
--- a/arch/parisc/lib/memcpy.c
+++ b/arch/parisc/lib/memcpy.c
@@ -405,7 +405,7 @@ byte_copy:
  unaligned_copy:
       /* possibly we are aligned on a word, but not on a double... */
-       if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
+       if (likely(t1 & (sizeof(unsigned int)-1) == 0)) {
               t2 = src & (sizeof(unsigned int) - 1);
                 if (unlikely(t2 != 0)) {
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