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>

Merged from: https://llvm.org/svn/llvm-project/polly/trunk@181987

llvm-svn: 183374

6 files changed, 51 insertions, 5 deletions

diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
index 06f0fa7854f7..753942fea211 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 136a87321f41..d5c3a9f43593 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 881a0ac24aaf..da0c782bc6d1 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");
diff --git a/polly/test/Cloog/CodeGen/loop_with_condition_nested.ll b/polly/test/Cloog/CodeGen/loop_with_condition_nested.ll
index 0ecdfe5ed75d..40a1fd89b44e 100644
--- a/polly/test/Cloog/CodeGen/loop_with_condition_nested.ll
+++ b/polly/test/Cloog/CodeGen/loop_with_condition_nested.ll
@@ -1,4 +1,5 @@
-; RUN: opt %loadPolly %defaultOpts -polly-cloog -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -basicaa -polly-cloog -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -basicaa -polly-codegen -loops -analyze < %s | FileCheck %s -check-prefix=LOOPS
 
 ;#include <string.h>
 ;#define N 1024
@@ -214,3 +215,7 @@ declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
 ; CHECK:     Stmt_9(c2);
 ; CHECK: }
 
+
+; LOOPS: Loop at depth 1 containing: %polly.loop_header<header>,%polly.stmt.,%polly.stmt.3<latch><exiting>
+; LOOPS: Loop at depth 1 containing: %polly.loop_header5<header>,%polly.stmt.11,%polly.stmt.12<latch><exiting>
+; LOOPS: Loop at depth 1 containing: %polly.loop_header15<header>,%polly.stmt.21<latch><exiting>
diff --git a/polly/test/Isl/CodeGen/loop_with_condition_nested.ll b/polly/test/Isl/CodeGen/loop_with_condition_nested.ll
index 188e293409e1..d6b710302d49 100644
--- a/polly/test/Isl/CodeGen/loop_with_condition_nested.ll
+++ b/polly/test/Isl/CodeGen/loop_with_condition_nested.ll
@@ -1,4 +1,6 @@
-; RUN: opt %loadPolly %defaultOpts -polly-ast -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -basicaa -polly-ast -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -basicaa -polly-codegen-isl -loops -analyze < %s | FileCheck %s -check-prefix=LOOPS
+
 
 ;#include <string.h>
 ;#define N 1024
@@ -209,3 +211,8 @@ declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
 ; CHECK:     Stmt_6(c1);
 ; CHECK:   Stmt_9(c1);
 ; CHECK: }
+
+; LOOPS: Printing analysis 'Natural Loop Information' for function 'loop_with_condition':
+; LOOPS: Loop at depth 1 containing: %1<header><exiting>,%2,%4,%7,%6,%8,%9,%10<latch>
+; LOOPS: Loop at depth 1 containing:
+; LOOPS: %polly.loop_header<header>,%polly.cond,%polly.merge,%polly.then,%polly.else,%polly.stmt.,%polly.cond3,%polly.merge4,%polly.then5,%polly.else6,%polly.stmt.7,%polly.stmt.8<latch><exiting>
diff --git a/polly/test/Isl/single_loop_param_less_equal.ll b/polly/test/Isl/single_loop_param_less_equal.ll
index 06d32085b637..fbc798ea36b9 100644
--- a/polly/test/Isl/single_loop_param_less_equal.ll
+++ b/polly/test/Isl/single_loop_param_less_equal.ll
@@ -1,5 +1,6 @@
 ; RUN: opt %loadPolly -polly-ast -analyze < %s | FileCheck %s
 ; RUN: opt %loadPolly -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=CODEGEN
+; RUN: opt %loadPolly -polly-codegen-isl -loops -analyze < %s | FileCheck %s -check-prefix=LOOPS
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-pc-linux-gnu"
 
@@ -57,3 +58,6 @@ ret:
 
 ; CODEGEN: polly.loop_preheader:
 ; CODEGEN:   br label %polly.loop_header
+
+; LOOPS: Loop at depth 1 containing: %loop.header<header><exiting>,%loop.body,%loop.backedge<latch>
+; LOOPS: Loop at depth 1 containing: %polly.loop_header<header>,%polly.stmt.loop.body<latch><exiting>