Bring forward the SPE code to later version of GCC

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• I think it is only deprecated in GCC 8. Is it easy to just build with SPE enabled?
• SPE for GCC 11?

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The thing that makes this more difficult is: https://gcc.gnu.org/legacy-ml/gcc-patches/2017-05/msg01227.html
Around late 2017 the SPE was split from the rs6000 which is what our Amiga SPEC file etc relies on.

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Closed as - won't happen.

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Re open. See pali/gcc-powerpcspe-musl@317a010

Check whether it is the target option combined with obsolete that is not being supported.

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wrt. above: that patch is talking about fixing the case when the build and host are different. When you build a cross compiler, the build == host, so if this patch is only doing what it says, and it looks like it is - I believe that will have no affect. It may have an affect when building the native compiler on a different build machine. After testing, it seemed not to have effect.

This: https://git.yoctoproject.org/meta-arm/tree/meta-arm-toolchain/recipes-devtools/gcc/gcc-arm-9.2/0036-Re-introduce-spe-commandline-options.patch?h=gatesgarth is useful, though. The spe option does not exist in our gcc 8+. But, it is not just re-installing that option that we need to do. We need the rs6000.c to actually use the set variable and generate different code if it is set. In 8.3.0, the set variable is no longer even used is rs6000.

It looks like it will be a combination of

• the https://git.yoctoproject.org/meta-arm/tree/meta-arm-toolchain/recipes-devtools/gcc/gcc-arm-9.2/0036-Re-introduce-spe-commandline-options.patch?h=gatesgarth
• Re-instating the code into the rs6000.c to actually use that set variable
• And, possibly, pali/gcc-powerpcspe-musl@317a010.

But, the first action is to get a cross compiler built, so at this stage I am not sure the latter matters - but may, soon.

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Another issue is the list of patches that have removed SPE support. For example:
https://gcc.gnu.org/pipermail/gcc-patches/2017-June/476140.html

Not sure I really want to take on this work without some sort of financial incentive! I remember now why I closed this ticket initially and said that it just won't happen.

It is not enough to just re-enable the SPE option in the .opt file - all the code has been removed from rs6000.c to actually do anything having set the option!