reg getInductionVariable

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#1

Hi,

The function getInductionVariable mandates the loop to be in “SimplifyForm”.

Loop::getInductionVariable(ScalarEvolution &SE) {
if (!isLoopSimplifyForm())
return nullptr;
…
…
}

bool Loop::isLoopSimplifyForm() {
return getLoopPreheader() && getLoopLatch() && hasDedicatedExits();

}

/// Return true if no exit block for the loop has a predecessor that is

/// outside the loop.
bool hasDedicatedExits() const;

Is it necessary for the loop to have DedicatedExists to find the induction variable?
Can this condition be relaxed?

#2

Potentially, but it is often simpler to force simplified form. If need
dedicated exists, split the exiting edges of a loop. That will create
dedicated exist blocks.

Cheers,
  Johannes