SOURCES: linux-gcc.patch (NEW) - don't overoptimize when using gcc 4.3

arekm arekm at pld-linux.org
Sun Jul 27 23:08:17 CEST 2008


Author: arekm                        Date: Sun Jul 27 21:08:17 2008 GMT
Module: SOURCES                       Tag: HEAD
---- Log message:
- don't overoptimize when using gcc 4.3

---- Files affected:
SOURCES:
   linux-gcc.patch (NONE -> 1.1)  (NEW)

---- Diffs:

================================================================
Index: SOURCES/linux-gcc.patch
diff -u /dev/null SOURCES/linux-gcc.patch:1.1
--- /dev/null	Sun Jul 27 23:08:17 2008
+++ SOURCES/linux-gcc.patch	Sun Jul 27 23:08:11 2008
@@ -0,0 +1,29 @@
+commit 38332cb98772f5ea757e6486bed7ed0381cb5f98
+Author: Segher Boessenkool <segher at kernel.crashing.org>
+Date:   Tue Mar 4 14:59:54 2008 -0800
+
+    time: prevent the loop in timespec_add_ns() from being optimised away
+    
+    Since some architectures don't support __udivdi3().
+    
+    Signed-off-by: Segher Boessenkool <segher at kernel.crashing.org>
+    Cc: john stultz <johnstul at us.ibm.com>
+    Cc: Ingo Molnar <mingo at elte.hu>
+    Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
+    Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
+
+diff --git a/include/linux/time.h b/include/linux/time.h
+index 2091a19..d32ef0a 100644
+--- a/include/linux/time.h
++++ b/include/linux/time.h
+@@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns)
+ {
+ 	ns += a->tv_nsec;
+ 	while(unlikely(ns >= NSEC_PER_SEC)) {
++		/* The following asm() prevents the compiler from
++		 * optimising this loop into a modulo operation.  */
++		asm("" : "+r"(ns));
++
+ 		ns -= NSEC_PER_SEC;
+ 		a->tv_sec++;
+ 	}
================================================================


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