On Apr 12 2018, Thomas König wrote:
with Fortran 2018, recursive is becoming the default. This will likely
have a serious impact on many user codes, which often declare large
arrays which could then overflow stacks, leading to segfaults without
further explanation.
Yes. Been there - seen that
On Thu, Apr 12, 2018 at 10:50 PM, Thomas König wrote:
> Hello world,
>
> with Fortran 2018, recursive is becoming the default. This will likely
> have a serious impact on many user codes, which often declare large
> arrays which could then overflow stacks, leading to segfaults without
> further ex
Hi,
We are trying to create a memory barrier with following testcase.
=
#include
void Test()
{
float fDivident = 0.1f;
float fResult = 0.0f;
fResult = ( fDivident / fResult );
__asm volatile ("mfence" ::: "memory");
printf("\nResult: %f\n", fResul
On Fri, 13 Apr 2018, Vivek Kinhekar wrote:
> The mfence instruction with memory clobber asm instruction should create a
> barrier between division and printf instructions.
No, floating-point division does not touch memory, so the asm does not (and
need not) restrict its motion.
Alexander
Thanks for the quick response, Alexander!
Regards,
Vivek Kinhekar
+91-7709046470
-Original Message-
From: Alexander Monakov
Sent: Friday, April 13, 2018 5:58 PM
To: Vivek Kinhekar
Cc: gcc@gcc.gnu.org
Subject: Re: GCC Compiler Optimization ignores or mistreats MFENCE memory
barrier rel
On Fri, Apr 13, 2018 at 12:50 AM, Thomas König wrote:
> Hello world,
>
> with Fortran 2018, recursive is becoming the default. This will likely
> have a serious impact on many user codes, which often declare large
> arrays which could then overflow stacks, leading to segfaults without
> further e
Hello Alexander,
In the given testcase, the generated fdivrs instruction performs the division
of a symbol ref (memory value) by FPU Stack Register and stores the value in
FPU Stack Register.
Please find the following RTL Dump of the fdivrs instruction generated. It
clearly access the memory
Oh! Thanks for the quick response, Jakub.
Regards,
Vivek Kinhekar
-Original Message-
From: Jakub Jelinek
Sent: Friday, April 13, 2018 7:08 PM
To: Vivek Kinhekar
Cc: Alexander Monakov ; gcc@gcc.gnu.org
Subject: Re: GCC Compiler Optimization ignores or mistreats MFENCE memory
barrier re
Hi,
I looked at a few performance anomalies between gfortran and Flang - it appears
array slices
are treated differently. Using -frepack-arrays fixed a performance issue in
gfortran and didn't
cause any regressions. Making input array slices contiguous helps both locality
and enables
more vecto
On Fri, Apr 13, 2018 at 01:34:21PM +, Vivek Kinhekar wrote:
> Hello Alexander,
>
> In the given testcase, the generated fdivrs instruction performs the
> division of a symbol ref (memory value) by FPU Stack Register and stores
> the value in FPU Stack Register.
The stack registers are not mem
On Fri, Apr 13, 2018 at 3:32 PM, Wilco Dijkstra wrote:
> Hi,
>
> I looked at a few performance anomalies between gfortran and Flang - it
> appears array slices
> are treated differently. Using -frepack-arrays fixed a performance issue in
> gfortran and didn't
> cause any regressions. Making inpu
Bin.Cheng wrote:
> I don't know the implementation of the option, so two questions:
> 1) When the repack is done during compilation? Is new code
> manipulating data layout added
> by frontend? If yes, better to do it during optimization thus is
> can be on demanding? This
> looks like
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