search for: createsimpleloopunrollpass

...createIndVarSimplifyPass()); // Canonicalize indvars MPM.add(createLoopIdiomPass()); // Recognize idioms like memset. addExtensionsToPM(EP_LateLoopOptimizations, MPM); MPM.add(createLoopDeletionPass()); // Delete dead loops .. if (!DisableUnrollLoops) MPM.add(createSimpleLoopUnrollPass(OptLevel)); // Unroll small loops I see -debug-pass=Structure output: Scalar Evolution Analysis Loop Pass Manager Induction Variable Simplification Recognize loop idioms Delete dead loops Unroll loops MergedLoadStoreMotion Which i...

...addExtensionsToPM(EP_LateLoopOptimizations, MPM); MPM.add(createLoopDeletionPass()); // Delete dead loops if (EnableLoopInterchange) { MPM.add(createLoopInterchangePass()); // Interchange loops MPM.add(createCFGSimplificationPass()); } if (!DisableUnrollLoops) MPM.add(createSimpleLoopUnrollPass()); // Unroll small loops addExtensionsToPM(EP_LoopOptimizerEnd, MPM); // <GVN is now immediately after loop optimizatons if (OptLevel > 1) { MPM.add(createMergedLoadStoreMotionPass()); // Merge ld/st in diamonds MPM.add(NewGVN ? createNewGVNPass() : crea...

I think this has to do with how the pass manager is populated when we give -O3 vs when we give particular pass names. Some passes have multiple createXYZPass() methods that accept arguments too. These methods call non-default pass constructors, which in turn cause the passes to behave in a different manner. eg: Pass *llvm::createLICMPass() { return new LegacyLICMPass(); } Pass