On 10/19/2017 06:37 AM, Richard Earnshaw (lists) wrote:
On 19/10/17 14:07, Wilco Dijkstra wrote:
Vladimir wrote:
+# Disable floating-point expression contraction
+LIBGCC2_FFP_CONTRAST_CFLAGS = -ffp-contract=off
+
It looks like this disables fp-contract in all of libgcc...
What is the the number of FMAs in libgcc before/after?
How can I find this number ?
dis <all functions in libgcc> | grep <all FMAs> | wc
Or are there the other simple ways ?
If it disables anything other than the ones in complex division, it
would have an unintended performance impact. It's best to do
this just for complex division.
Wilco
It's probably better to do this with an attribute
__attribute__((optimize("fp-contract=off")))
on the affected functions.
I like your suggestion.
-Vladimir
R.
