Update LoopInfo correctly

When the Polly code generation was written we did not correctly update the
LoopInfo data, but still claimed that the loop information is correct. This
does not only lead to missed optimizations, but it can also cause
miscompilations in case passes such as LoopSimplify are run after Polly.

Reported-by: Sergei Larin <slarin@codeaurora.org>
llvm-svn: 181987

3 files changed, 33 insertions, 3 deletions

diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
index 06f0fa7854f..753942fea21 100644
--- a/polly/lib/CodeGen/CodeGeneration.cpp
+++ b/polly/lib/CodeGen/CodeGeneration.cpp
@@ -924,6 +924,13 @@ void ClastStmtCodeGen::codegen(const clast_guard *g) {
   Builder.CreateBr(MergeBB);
   Builder.SetInsertPoint(ThenBB->begin());
 
+  LoopInfo &LI = P->getAnalysis<LoopInfo>();
+  Loop *L = LI.getLoopFor(CondBB);
+  if (L) {
+    L->addBasicBlockToLoop(ThenBB, LI.getBase());
+    L->addBasicBlockToLoop(MergeBB, LI.getBase());
+  }
+
   codegen(g->then);
 
   Builder.SetInsertPoint(MergeBB->begin());
@@ -1030,8 +1037,6 @@ public:
 
     AU.addPreserved<CloogInfo>();
     AU.addPreserved<Dependences>();
-
-    // FIXME: We do not create LoopInfo for the newly generated loops.
     AU.addPreserved<LoopInfo>();
     AU.addPreserved<DominatorTree>();
     AU.addPreserved<ScopDetection>();
diff --git a/polly/lib/CodeGen/IslCodeGeneration.cpp b/polly/lib/CodeGen/IslCodeGeneration.cpp
index 136a87321f4..d5c3a9f4359 100644
--- a/polly/lib/CodeGen/IslCodeGeneration.cpp
+++ b/polly/lib/CodeGen/IslCodeGeneration.cpp
@@ -860,6 +860,13 @@ void IslNodeBuilder::createIf(__isl_take isl_ast_node *If) {
   DT.addNewBlock(ElseBB, CondBB);
   DT.changeImmediateDominator(MergeBB, CondBB);
 
+  LoopInfo &LI = P->getAnalysis<LoopInfo>();
+  Loop *L = LI.getLoopFor(CondBB);
+  if (L) {
+    L->addBasicBlockToLoop(ThenBB, LI.getBase());
+    L->addBasicBlockToLoop(ElseBB, LI.getBase());
+  }
+
   CondBB->getTerminator()->eraseFromParent();
 
   Builder.SetInsertPoint(CondBB);
@@ -1051,7 +1058,6 @@ public:
 
     AU.addPreserved<Dependences>();
 
-    // FIXME: We do not create LoopInfo for the newly generated loops.
     AU.addPreserved<LoopInfo>();
     AU.addPreserved<DominatorTree>();
     AU.addPreserved<IslAstInfo>();
diff --git a/polly/lib/CodeGen/LoopGenerators.cpp b/polly/lib/CodeGen/LoopGenerators.cpp
index 881a0ac24aa..da0c782bc6d 100644
--- a/polly/lib/CodeGen/LoopGenerators.cpp
+++ b/polly/lib/CodeGen/LoopGenerators.cpp
@@ -15,6 +15,7 @@
 #include "polly/ScopDetection.h"
 #include "polly/CodeGen/LoopGenerators.h"
 #include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -50,6 +51,7 @@ Value *polly::createLoop(Value *LB, Value *UB, Value *Stride,
                          ICmpInst::Predicate Predicate) {
 
   DominatorTree &DT = P->getAnalysis<DominatorTree>();
+  LoopInfo &LI = P->getAnalysis<LoopInfo>();
   Function *F = Builder.GetInsertBlock()->getParent();
   LLVMContext &Context = F->getContext();
 
@@ -63,6 +65,23 @@ Value *polly::createLoop(Value *LB, Value *UB, Value *Stride,
   BasicBlock *PreHeaderBB =
       BasicBlock::Create(Context, "polly.loop_preheader", F);
 
+  // Update LoopInfo
+  Loop *OuterLoop = LI.getLoopFor(BeforeBB);
+  Loop *NewLoop = new Loop();
+
+  if (OuterLoop) {
+    OuterLoop->addChildLoop(NewLoop);
+  } else {
+    LI.addTopLevelLoop(NewLoop);
+  }
+
+  if (OuterLoop) {
+    OuterLoop->addBasicBlockToLoop(GuardBB, LI.getBase());
+    OuterLoop->addBasicBlockToLoop(PreHeaderBB, LI.getBase());
+  }
+
+  NewLoop->addBasicBlockToLoop(HeaderBB, LI.getBase());
+
   // ExitBB
   ExitBB = SplitBlock(BeforeBB, Builder.GetInsertPoint()++, P);
   ExitBB->setName("polly.loop_exit");