[MacPorts] #37846: cctools as does not support AVX, consider using llvm

[MacPorts]

#37846: cctools as does not support AVX, consider using llvm
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  Reporter:  wd11@…       |      Owner:  macports-tickets@…
      Type:  defect       |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.1.2
Resolution:               |   Keywords:
      Port:  cctools gcc  |
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Comment (by raimue):

 These AVX instructions are not emitted by gcc; the example code uses
 intrinsics. gcc does not validate that, it just passes it through to the
 assembler like it always does for inline assembler code.

 I do not know or check whether gcc on macOS would emit AVX code from C
 code (keyword: auto-vectorization).

 If we want to support this, we need to modify the gcc ports in MacPorts to
 use the LLVM assembler. The simplest option seems to be to use `--with-
 as=/usr/bin/as` (maybe the same for the other target tools that are now
 provided by cctools?).

 But this can only be done on macOS and Xcode version combinations that
 already use the LLVM assembler by default and not the old cctools. You
 need to find out which these are. Older versions should continue to use
 cctools, as that is still newer than what is provided in `/usr/bin`.

 Then test this setup and report back.

-- 
Ticket URL: <https://trac.macports.org/ticket/37846#comment:13>
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