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uwplse / herbgrind

A Valgrind tool for Herbie
GNU General Public License v3.0
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need help with microbenchmark #36

Closed sangeeta0201 closed 5 years ago

sangeeta0201 commented 5 years ago

Hi,

I have been running John Walker's benchmark which performs a fast Fourier transform of a square matrix, unfortunately, Herbgrind reports "No Marks found".

./herbgrind.sh bench/ffbench.c.out
==5847== Herbgrind, a valgrind tool for Herbie
==5847== Copyright (C) 2016-2017, and GNU GPL'd, by Alex Sanchez-Stern
==5847== Using Valgrind-3.12.0.SVN and LibVEX; rerun with -h for copyright info
==5847== Command: bench/ffbench.c.out
==5847== 
4 passes.  No errors in results.
==5847== 
Didn't find any marks!

# cat ffbench.c.out.gh 
No marks found!
pavpanchekha commented 5 years ago

@sangeeta0201 what sort of response are you looking for? Does the benchmark perform any output? Herbgrind considers a floating-point expression relevant if it is connected by control flow to some output. (This is also the definition used by C compilers, which can generally delete dead code.) It is not clear that the benchmark does. If you add some code to, say, output the transformed matrix, Herbgrind would find some marks.

HazardousPeach commented 5 years ago

It looks like this issue is due to a benchmark which doesn't produce any output, so I'm going to close this issue. Feel free to correct me if I'm wrong.