As a result of my proposed patch at <https://reviews.llvm.org/D24481> being reverted b/c it breaks test-suite tests that either expect exact equality [as this one, i.e. "telecomm-FFT", currently does] or too-strict tolerance, I am investigating 20 tests and working on solutions. This is the first publicly-proposed solution, or at least the beginnings of one.
The first problem with "telecomm-FFT" is that the test is currently configured to capture the output [688111 bytes of floating-point text, including lots of spaces and just a few newlines], hash it, throw away the original text, then compare the hashes. Unless somebody wants to rewrite this test in integer code [good luck ;-)], this obviously won`t "do".
Does anybody know of a way to have test-suite automatically uncompress a compressed reference file, run the test and compare [with "fpcmp" and a tolerance, in this case], then delete the temporarily-uncompressed reference file and compress the raw output [for post-run analysis]? I don`t yet know enough about the inner workings of test-suite to write that by myself.
As for the tolerance, I experimentally derived the absolute tolerance 0.000002 using [after minimization] the following:
> ../../../../tools/fpcmp -a 0.000001 new_reference_output /work/Abe/Sept._27_2016/LLVM_test-suite_build_004___AArch64___Clang_2016-09-07-20-03-19-b0768e8-master/MultiSource/Benchmarks/MiBench/telecomm-FFT/new_reference_output
../../../../tools/fpcmp: Compared: 3.610700e-02 and 3.610600e-02
abs. diff = 1.000000e-06 rel.diff = 2.769623e-05
Out of tolerance: rel/abs: 0.000000e+00/1.000000e-06
> ../../../../tools/fpcmp -a 0.000002 new_reference_output /work/Abe/Sept._27_2016/LLVM_test-suite_build_004___AArch64___Clang_2016-09-07-20-03-19-b0768e8-master/MultiSource/Benchmarks/MiBench/telecomm-FFT/new_reference_output
> echo $?
... where the two runs were both on the same AArch64 device, once built with a compiler from this commit:
Author: George Burgess IV <firstname.lastname@example.org>
... and the other with my fusion-enabling patch on top of that.