patch for hp-timing.h

[Wilco Dijkstra]

Hi Jun,

> hp-timing is only used on benchtest today, but it can be used on other
> measurements in the future.

It can't as proposed below since this would overflow in ~16 seconds.
We could improve this by removing the zero bits from the multiply
and doing some shifts, maybe that will make the interval long enough
for integer multiply. Otherwise I'd suggest the floating point version since
it's not like the benchtests don't already use floating point.

Cheers,
Wilco

diff --git a/benchtests/Makefile b/benchtests/Makefile
index 292976b26b..a624614207 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -499,4 +499,5 @@ $(objpfx)bench-%.c: %-inputs $(bench-deps)
 	  cat $($*-INCLUDE); \
 	fi; \
 	$(PYTHON) scripts/bench.py $(patsubst %-inputs,%,$<); } > $@-tmp
+	cp -f $@-tmp $@-bak

Unintended change I guess?

 	mv -f $@-tmp $@
diff --git a/sysdeps/aarch64/hp-timing.h b/sysdeps/aarch64/hp-timing.h
index f7f7ac7cae..c699effe6a 100644
--- a/sysdeps/aarch64/hp-timing.h
+++ b/sysdeps/aarch64/hp-timing.h
@@ -41,7 +41,7 @@ typedef uint64_t hp_timing_t;
 #define HP_TIMING_DIFF(Diff, Start, End)			\
 ({  hp_timing_t freq;						\
     __asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq));	\
-   (Diff) = ((End) - (Start)) * (UINT64_C(1000000000) / freq);	\
+   (Diff) = (((End) - (Start)) * UINT64_C(1000000000)) / freq; \
 })
 
 #endif	/* hp-timing.h */