GCC 7 Release Series – Changes, New Features, and Fixes

Re:GCC 7 Release Series – Changes, New Features, and Fixes by DannyBee on Sunday April 09, 2017 @01:05PM (#14073229)

No, it's correct. It's saying "if they are always computed, we move them up".

  if (a)
    foo = a + b
  else b 
    foo = a + b
  ->
  foo = a+b
  if (a)
  else (b)

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Re:GCC 7 Release Series – Changes, New Features, and Fixes by fenollp on Sunday April 09, 2017 @02:05PM (#14073519)

Possible side effects correction:

    ->
      if (a)
      else (b)
      foo = a+b

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Re:GCC 7 Release Series – Changes, New Features, and Fixes by mindleyhilner on Sunday April 09, 2017 @01:09PM (#14073242)

How do you move up towards exit?

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Re:GCC 7 Release Series – Changes, New Features, and Fixes by evilpie on Sunday April 09, 2017 @01:29PM (#14073338)

I think you have to read it like "executed on >all paths to the function exit< as early as possible". As in, if you have an expression that is always executed regardless which path you take before returning. It's useful to move that expression upwards instead of having copies on the different paths to the function exit.

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Re:GCC 7 Release Series – Changes, New Features, and Fixes by sanjoy_das on Sunday April 09, 2017 @05:02PM (#14074346)

My guess is that they meant "up" in the sense of "up in post dominator tree".

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