diff --git a/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h b/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h --- a/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h +++ b/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h @@ -356,6 +356,16 @@ Worklist.insert(CurrentL); } + bool isLoopNestChanged() const { + return LoopNestChanged; + } + + /// Loopnest passes should use this method to indicate if the + /// loopnest has been modified. + void markLoopNestChanged(bool Changed) { + LoopNestChanged = Changed; + } + private: friend class llvm::FunctionToLoopPassAdaptor; @@ -368,6 +378,7 @@ Loop *CurrentL; bool SkipCurrentLoop; const bool LoopNestMode; + bool LoopNestChanged; #ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS // In debug builds we also track the parent loop to implement asserts even in @@ -376,8 +387,10 @@ #endif LPMUpdater(SmallPriorityWorklist &Worklist, - LoopAnalysisManager &LAM, bool LoopNestMode = false) - : Worklist(Worklist), LAM(LAM), LoopNestMode(LoopNestMode) {} + LoopAnalysisManager &LAM, bool LoopNestMode = false, + bool LoopNestChanged = false) + : Worklist(Worklist), LAM(LAM), LoopNestMode(LoopNestMode), + LoopNestChanged(LoopNestChanged) {} }; template diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp --- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp +++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp @@ -44,6 +44,7 @@ #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Scalar/LoopPassManager.h" #include "llvm/Transforms/Utils/BasicBlockUtils.h" #include "llvm/Transforms/Utils/LoopUtils.h" #include @@ -1766,5 +1767,6 @@ OptimizationRemarkEmitter ORE(&F); if (!LoopInterchange(&AR.SE, &AR.LI, &DI, &AR.DT, CC, &ORE).run(LN)) return PreservedAnalyses::all(); + U.markLoopNestChanged(true); return getLoopPassPreservedAnalyses(); } diff --git a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp --- a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp +++ b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp @@ -84,6 +84,7 @@ // invalid when encountering a loop-nest pass. std::unique_ptr LoopNestPtr; bool IsLoopNestPtrValid = false; + Loop *OuterMostLoop = &L; for (size_t I = 0, E = IsLoopNestPass.size(); I != E; ++I) { Optional PassPA; @@ -97,10 +98,18 @@ // If the loop-nest object calculated before is no longer valid, // re-calculate it here before running the loop-nest pass. - if (!IsLoopNestPtrValid) { - LoopNestPtr = LoopNest::getLoopNest(L, AR.SE); + // + // FIXME: PreservedAnalysis should not be abused to tell if the + // status of loopnest has been changed. We should use and only + // use LPMUpdater for this purpose. + if (!IsLoopNestPtrValid || U.isLoopNestChanged()) { + while (auto *ParentLoop = OuterMostLoop->getParentLoop()) + OuterMostLoop = ParentLoop; + LoopNestPtr = LoopNest::getLoopNest(*OuterMostLoop, AR.SE); IsLoopNestPtrValid = true; + U.markLoopNestChanged(false); } + PassPA = runSinglePass(*LoopNestPtr, Pass, AM, AR, U, PI); } @@ -118,7 +127,7 @@ // Update the analysis manager as each pass runs and potentially // invalidates analyses. - AM.invalidate(L, *PassPA); + AM.invalidate(IsLoopNestPass[I] ? *OuterMostLoop : L, *PassPA); // Finally, we intersect the final preserved analyses to compute the // aggregate preserved set for this pass manager. @@ -130,7 +139,7 @@ // After running the loop pass, the parent loop might change and we need to // notify the updater, otherwise U.ParentL might gets outdated and triggers // assertion failures in addSiblingLoops and addChildLoops. - U.setParentLoop(L.getParentLoop()); + U.setParentLoop((IsLoopNestPass[I] ? *OuterMostLoop : L).getParentLoop()); } return PA; } diff --git a/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-4.ll b/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-4.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/LoopInterchange/interchanged-loop-nest-4.ll @@ -0,0 +1,53 @@ +; REQUIRES: asserts +; RUN: opt < %s -passes="loop(loop-interchange,loop-interchange)" -cache-line-size=8 -verify-dom-info -verify-loop-info \ +; RUN: -debug-only=loop-interchange 2>&1 | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +@g_75 = external global i32, align 1 +@g_78 = external global [6 x ptr], align 1 + +; Loop interchange as a loopnest pass should always construct the loop nest from +; the outermost loop. This test case runs loop interchange twice. In the loop pass +; manager, it might occur that after the first loop interchange transformation +; the original outermost loop becomes a inner loop hence the loop nest constructed +; afterwards for the second loop interchange pass turns out to be a loop list of size +; 2 and is not valid. This causes functional issues. +; +; Make sure we always construct the valid and correct loop nest at the beginning +; of execution of a loopnest pass. + +; CHECK: Processing LoopList of size = 3 +; CHECK: Processing LoopList of size = 3 +define void @loopnest_01() { +entry: + br label %for.cond5.preheader.i.i.i + +for.cond5.preheader.i.i.i: ; preds = %for.end16.i.i.i, %entry + %storemerge11.i.i.i = phi i32 [ 4, %entry ], [ %sub18.i.i.i, %for.end16.i.i.i ] + br label %for.cond8.preheader.i.i.i + +for.cond8.preheader.i.i.i: ; preds = %for.inc14.i.i.i, %for.cond5.preheader.i.i.i + %l_105.18.i.i.i = phi i16 [ 0, %for.cond5.preheader.i.i.i ], [ %add15.i.i.i, %for.inc14.i.i.i ] + br label %for.body10.i.i.i + +for.body10.i.i.i: ; preds = %for.body10.i.i.i, %for.cond8.preheader.i.i.i + %storemerge56.i.i.i = phi i16 [ 5, %for.cond8.preheader.i.i.i ], [ %sub.i.i.i, %for.body10.i.i.i ] + %arrayidx.i.i.i = getelementptr [6 x ptr], ptr @g_78, i16 0, i16 %storemerge56.i.i.i + store ptr @g_75, ptr %arrayidx.i.i.i, align 1 + %sub.i.i.i = add nsw i16 %storemerge56.i.i.i, -1 + br i1 true, label %for.inc14.i.i.i, label %for.body10.i.i.i + +for.inc14.i.i.i: ; preds = %for.body10.i.i.i + %add15.i.i.i = add nuw nsw i16 %l_105.18.i.i.i, 1 + %exitcond.not.i.i.i = icmp eq i16 %add15.i.i.i, 6 + br i1 %exitcond.not.i.i.i, label %for.end16.i.i.i, label %for.cond8.preheader.i.i.i + +for.end16.i.i.i: ; preds = %for.inc14.i.i.i + %sub18.i.i.i = add nsw i32 %storemerge11.i.i.i, -1 + %cmp.i10.not.i.i = icmp eq i32 %storemerge11.i.i.i, 0 + br i1 %cmp.i10.not.i.i, label %func_4.exit.i, label %for.cond5.preheader.i.i.i + +func_4.exit.i: ; preds = %for.end16.i.i.i + unreachable +}