(0.33) Make versioner skip loops that have become acyclic during the pass #147
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The region structure is expected to be a loop. If it isn't, then versioner may misbehave, e.g. it may crash. And besides, there's no point in trying to version an acyclic region anyway. HCR guard versioning removes edges from the CFG immediately (unlike versioning of regular conditionals/virtual guards, which leaves a trivially foldable conditional tree in place). The removal of particular edges can change loops into acyclic regions, so skip any region that is no longer a loop. (OSR guard versioning also removes edges immediately, but the targets of those edges are not within any loop, so their removal can't change loops into acyclic regions.)
vijaysun-omr
approved these changes
Jun 2, 2022
pshipton
approved these changes
Jun 7, 2022
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This is the 0.33 PR for eclipse-omr/omr#6531, with the exact same commit that was merged earlier today into eclipse/omr:master