ExtVec.h: add long double x2 x4 in ExtVecTraits for AArch64

[davidlt]

The patch adds suport for long double vectors. This revealed GCC
bugs on i*86/x86_64/aarch64 (links below). Only done for AArch64,
as this would ICE GCC on x86_64 until fixed.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65486
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65491

Signed-off-by: David Abdurachmanov davidlt@cern.ch

[cmsbuild]

A new Pull Request was created by @davidlt for CMSSW_7_5_X.

ExtVec.h: add long double x2 x4 in ExtVecTraits for AArch64

It involves the following packages:

DataFormats/Math

@cmsbuild, @cvuosalo, @nclopezo, @slava77 can you please review it and eventually sign? Thanks.
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[davidlt]

There is no need for compile and similar tests as this file is not used on x86_64.

Merge made by the 'recursive' strategy.
 DataFormats/Math/interface/ExtVec.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
Switched to branch 'from-CMSSW_7_5_X_2015-03-19-2300'
>> Checking DataFormats/Math CMSSW_7_5_X_2015-03-19-2300
   x DataFormats/Math/interface/ExtVec.h
Checking out these packages: 0

I found only place in CMSSW (apart from tests) which actually uses long double (x2 and x4) vectors (aka Vec2 and Vec4): RecoMuon/TrackerSeedGenerator/interface/L1MuonPixelTrackFitter.h

   24 class L1MuonPixelTrackFitter : public PixelFitter {
     25
     26 public:
     27   class Circle {
     28   public:
     29     typedef Vector3DBase< long double, GlobalTag>  Vector;
     30     typedef  Point3DBase< long double, GlobalTag>  Point;

Lines 29-30.

[VinInn]

L1MuonPixelTrackFitter should be modified to use plain double....

[slava77]

+1

for #8456 fe1c2a1
the change affects only aarch64; it looks OK visually.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_5_X IBs unless changes or unless it breaks tests. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @nclopezo, @ktf, @smuzaffar