Refactor simplifySCoP [NFC]

  Remove obsolete code and decrease the indention in the
  Scop::simplifySCoP() function.

llvm-svn: 269049

3 files changed, 49 insertions, 72 deletions

diff --git a/polly/include/polly/ScopInfo.h b/polly/include/polly/ScopInfo.h
index ba086f8facf..75eb2547f85 100644
--- a/polly/include/polly/ScopInfo.h
+++ b/polly/include/polly/ScopInfo.h
@@ -1156,10 +1156,6 @@ public:
   /// statements, return its entry block.
   BasicBlock *getEntryBlock() const;
 
-  /// @brief Return RegionInfo's RegionNode for this statements' BB or
-  ///        subregion.
-  RegionNode *getRegionNode() const;
-
   /// @brief Return true if this statement does not contain any accesses.
   bool isEmpty() const { return MemAccs.empty(); }
 
@@ -1614,28 +1610,11 @@ private:
   bool buildDomains(Region *R, ScopDetection &SD, DominatorTree &DT,
                     LoopInfo &LI);
 
-  /// @brief Check if a region part should be represented in the SCoP or not.
-  ///
-  /// If @p RN does not contain any useful calculation or is only reachable
-  /// via error blocks we do not model it in the polyhedral representation.
-  ///
-  /// @param RN The region part to check.
-  /// @param DT The DominatorTree for the current function.
-  /// @param LI The LoopInfo for the current function.
-  ///
-  /// @return True if the part should be ignored, otherwise false.
-  bool isIgnored(RegionNode *RN, DominatorTree &DT, LoopInfo &LI);
-
   /// @brief Add parameter constraints to @p C that imply a non-empty domain.
   __isl_give isl_set *addNonEmptyDomainConstraints(__isl_take isl_set *C) const;
 
   /// @brief Simplify the SCoP representation
-  ///
-  /// At the moment we perform the following simplifications:
-  ///   - removal of no-op statements
-  /// @param RemoveIgnoredStmts If true, also removed ignored statments.
-  /// @see isIgnored()
-  void simplifySCoP(bool RemoveIgnoredStmts, DominatorTree &DT, LoopInfo &LI);
+  void simplifySCoP(bool AfterHoisting, DominatorTree &DT, LoopInfo &LI);
 
   /// @brief Create equivalence classes for required invariant accesses.
   ///
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 72f4e25c539..cb192f8e966 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1657,12 +1657,6 @@ BasicBlock *ScopStmt::getEntryBlock() const {
   return getRegion()->getEntry();
 }
 
-RegionNode *ScopStmt::getRegionNode() const {
-  if (isRegionStmt())
-    return getRegion()->getNode();
-  return getParent()->getRegion().getBBNode(getBasicBlock());
-}
-
 unsigned ScopStmt::getNumParams() const { return Parent.getNumParams(); }
 
 unsigned ScopStmt::getNumIterators() const { return NestLoops.size(); }
@@ -2274,7 +2268,7 @@ bool Scop::buildDomains(Region *R, ScopDetection &SD, DominatorTree &DT,
   DomainMap[EntryBB] = S;
 
   if (IsOnlyNonAffineRegion)
-    return true;
+    return !containsErrorBlock(R->getNode(), *R, LI, DT);
 
   if (!buildDomainsWithBranchConstraints(R, SD, DT, LI))
     return false;
@@ -3087,9 +3081,9 @@ void Scop::init(AliasAnalysis &AA, AssumptionCache &AC, ScopDetection &SD,
 
   addUserAssumptions(AC, DT, LI);
 
-  // Remove empty and ignored statements.
+  // Remove empty statements.
   // Exit early in case there are no executable statements left in this scop.
-  simplifySCoP(true, DT, LI);
+  simplifySCoP(false, DT, LI);
   if (Stmts.empty())
     return;
 
@@ -3116,7 +3110,7 @@ void Scop::init(AliasAnalysis &AA, AssumptionCache &AC, ScopDetection &SD,
 
   hoistInvariantLoads(SD);
   verifyInvariantLoads(SD);
-  simplifySCoP(false, DT, LI);
+  simplifySCoP(true, DT, LI);
 }
 
 Scop::~Scop() {
@@ -3180,20 +3174,16 @@ void Scop::updateAccessDimensionality() {
       Access->updateDimensionality();
 }
 
-void Scop::simplifySCoP(bool RemoveIgnoredStmts, DominatorTree &DT,
-                        LoopInfo &LI) {
+void Scop::simplifySCoP(bool AfterHoisting, DominatorTree &DT, LoopInfo &LI) {
   for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
     ScopStmt &Stmt = *StmtIt;
-    RegionNode *RN = Stmt.getRegionNode();
 
-    bool RemoveStmt = StmtIt->isEmpty();
+    bool RemoveStmt = Stmt.isEmpty();
     if (!RemoveStmt)
       RemoveStmt = isl_set_is_empty(DomainMap[Stmt.getEntryBlock()]);
-    if (!RemoveStmt)
-      RemoveStmt = (RemoveIgnoredStmts && isIgnored(RN, DT, LI));
 
     // Remove read only statements only after invariant loop hoisting.
-    if (!RemoveStmt && !RemoveIgnoredStmts) {
+    if (!RemoveStmt && AfterHoisting) {
       bool OnlyRead = true;
       for (MemoryAccess *MA : Stmt) {
         if (MA->isRead())
@@ -3206,19 +3196,19 @@ void Scop::simplifySCoP(bool RemoveIgnoredStmts, DominatorTree &DT,
       RemoveStmt = OnlyRead;
     }
 
-    if (RemoveStmt) {
-      // Remove the statement because it is unnecessary.
-      if (Stmt.isRegionStmt())
-        for (BasicBlock *BB : Stmt.getRegion()->blocks())
-          StmtMap.erase(BB);
-      else
-        StmtMap.erase(Stmt.getBasicBlock());
-
-      StmtIt = Stmts.erase(StmtIt);
+    if (!RemoveStmt) {
+      StmtIt++;
       continue;
     }
 
-    StmtIt++;
+    // Remove the statement because it is unnecessary.
+    if (Stmt.isRegionStmt())
+      for (BasicBlock *BB : Stmt.getRegion()->blocks())
+        StmtMap.erase(BB);
+    else
+      StmtMap.erase(Stmt.getBasicBlock());
+
+    StmtIt = Stmts.erase(StmtIt);
   }
 }
 
@@ -3922,29 +3912,6 @@ bool Scop::restrictDomains(__isl_take isl_union_set *Domain) {
 
 ScalarEvolution *Scop::getSE() const { return SE; }
 
-bool Scop::isIgnored(RegionNode *RN, DominatorTree &DT, LoopInfo &LI) {
-  BasicBlock *BB = getRegionNodeBasicBlock(RN);
-  ScopStmt *Stmt = getStmtFor(RN);
-
-  // If there is no stmt, then it already has been removed.
-  if (!Stmt)
-    return true;
-
-  // Check if there are accesses contained.
-  if (Stmt->isEmpty())
-    return true;
-
-  // Check for reachability via non-error blocks.
-  if (!DomainMap.count(BB))
-    return true;
-
-  // Check if error blocks are contained.
-  if (containsErrorBlock(RN, getRegion(), LI, DT))
-    return true;
-
-  return false;
-}
-
 struct MapToDimensionDataTy {
   int N;
   isl_union_pw_multi_aff *Res;
diff --git a/polly/test/Isl/CodeGen/only_non_affine_error_region.ll b/polly/test/Isl/CodeGen/only_non_affine_error_region.ll
new file mode 100644
index 00000000000..e8ba7686343
--- /dev/null
+++ b/polly/test/Isl/CodeGen/only_non_affine_error_region.ll
@@ -0,0 +1,31 @@
+; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
+;
+; CHECK-NOT: polly.start
+;
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; Function Attrs: nounwind uwtable
+define void @f(i32 %argc, i32* %A) #0 {
+entry:
+  br i1 undef, label %for.end, label %for.body
+
+for.body:                                         ; preds = %entry
+  br label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  %i.2 = phi i32 [ 1, %entry ], [ 1, %for.body ]
+  %cmp170 = icmp eq i32 %i.2, %argc
+  br i1 %cmp170, label %if.then172, label %if.end174
+
+if.then172:                                       ; preds = %for.end
+  %0 = load i32, i32* %A
+  tail call void @usage()
+  br label %if.end174
+
+if.end174:                                        ; preds = %if.then172, %for.end
+  %idxprom175 = sext i32 %i.2 to i64
+  ret void
+}
+
+; Function Attrs: nounwind uwtable
+declare void @usage()