[ScopBuilder] Split statements on encountering store instructions.

Introduce -polly-stmt-granularity=store option.

Contributed-by: Nandini Singhal <cs15mtech01004@iith.ac.in>

Differential Revision: https://reviews.llvm.org/D37337

llvm-svn: 320360

polly/include/polly/ScopBuilder.h

@@ -233,7 +233,7 @@ class ScopBuilder {
   ///
   /// Consecutive instructions are associated to the same statement until a
   /// separator is found.
-  void buildSequentialBlockStmts(BasicBlock *BB);
+  void buildSequentialBlockStmts(BasicBlock *BB, bool SplitOnStore = false);
 
   /// Create one or more ScopStmts for @p BB using equivalence classes.
   ///

polly/lib/Analysis/ScopBuilder.cpp

@@ -103,7 +103,7 @@ static cl::opt<bool> DisableMultiplicativeReductions(
     cl::desc("Disable multiplicative reductions"), cl::Hidden, cl::ZeroOrMore,
     cl::init(false), cl::cat(PollyCategory));
 
-enum class GranularityChoice { BasicBlocks, ScalarIndependence };
+enum class GranularityChoice { BasicBlocks, ScalarIndependence, Stores };
 
 static cl::opt<GranularityChoice> StmtGranularity(
     "polly-stmt-granularity",
@@ -112,7 +112,9 @@ static cl::opt<GranularityChoice> StmtGranularity(
     cl::values(clEnumValN(GranularityChoice::BasicBlocks, "bb",
                           "One statement per basic block"),
                clEnumValN(GranularityChoice::ScalarIndependence, "scalar-indep",
-                          "Scalar independence heuristic")),
+                          "Scalar independence heuristic"),
+               clEnumValN(GranularityChoice::Stores, "store",
+                          "Store-level granularity")),
     cl::init(GranularityChoice::BasicBlocks), cl::cat(PollyCategory));
 
 void ScopBuilder::buildPHIAccesses(ScopStmt *PHIStmt, PHINode *PHI,
@@ -686,15 +688,16 @@ bool ScopBuilder::shouldModelInst(Instruction *Inst, Loop *L) {
          !canSynthesize(Inst, *scop, &SE, L);
 }
 
-void ScopBuilder::buildSequentialBlockStmts(BasicBlock *BB) {
+void ScopBuilder::buildSequentialBlockStmts(BasicBlock *BB, bool SplitOnStore) {
   Loop *SurroundingLoop = LI.getLoopFor(BB);
 
   int Count = 0;
   std::vector<Instruction *> Instructions;
   for (Instruction &Inst : *BB) {
     if (shouldModelInst(&Inst, SurroundingLoop))
       Instructions.push_back(&Inst);
-    if (Inst.getMetadata("polly_split_after")) {
+    if (Inst.getMetadata("polly_split_after") ||
+        (SplitOnStore && isa<StoreInst>(Inst))) {
       scop->addScopStmt(BB, SurroundingLoop, Instructions, Count);
       Count++;
       Instructions.clear();
@@ -900,6 +903,9 @@ void ScopBuilder::buildStmts(Region &SR) {
       case GranularityChoice::ScalarIndependence:
         buildEqivClassBlockStmts(BB);
         break;
+      case GranularityChoice::Stores:
+        buildSequentialBlockStmts(BB, true);
+        break;
       }
     }
 }

polly/test/ScopInfo/stmt_split_on_store.ll

@@ -0,0 +1,62 @@
+; RUN: opt %loadPolly -polly-scops -analyze -polly-stmt-granularity=store -polly-print-instructions < %s | FileCheck %s
+
+;      void func(int *A, int *B){
+;        for (int i = 0; i < 1024; i+=1) {
+;      Stmt:
+;          A[i] = i;
+;          B[i] = i;
+;        }
+;      }
+;
+; CHECK:    Statements {
+; CHECK-NEXT: 	Stmt_Stmt
+; CHECK-NEXT:       Domain :=
+; CHECK-NEXT:           { Stmt_Stmt[i0] : 0 <= i0 <= 1023 };
+; CHECK-NEXT:       Schedule :=
+; CHECK-NEXT:           { Stmt_Stmt[i0] -> [i0, 0] };
+; CHECK-NEXT:       MustWriteAccess :=	[Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:           { Stmt_Stmt[i0] -> MemRef_A[i0] };
+; CHECK-NEXT:       Instructions {
+; CHECK-NEXT:             store i32 %i.0, i32* %arrayidx, align 4
+; CHECK-NEXT:       }
+; CHECK-NEXT:  	Stmt_Stmt1
+; CHECK-NEXT:       Domain :=
+; CHECK-NEXT:           { Stmt_Stmt1[i0] : 0 <= i0 <= 1023 };
+; CHECK-NEXT:       Schedule :=
+; CHECK-NEXT:           { Stmt_Stmt1[i0] -> [i0, 1] };
+; CHECK-NEXT:       MustWriteAccess :=	[Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:           { Stmt_Stmt1[i0] -> MemRef_B[i0] };
+; CHECK-NEXT:       Instructions {
+; CHECK-NEXT:             store i32 %i.0, i32* %arrayidx2, align 4
+; CHECK-NEXT:       }
+; CHECK-NEXT:    }
+;
+; Function Attrs: noinline nounwind uwtable
+define void @func(i32* %A, i32* %B) #0 {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %i.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ]
+  %cmp = icmp slt i32 %i.0, 1024
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  br label %Stmt
+
+Stmt:                                             ; preds = %for.body
+  %idxprom = sext i32 %i.0 to i64
+  %arrayidx = getelementptr inbounds i32, i32* %A, i64 %idxprom
+  store i32 %i.0, i32* %arrayidx, align 4
+  %idxprom1 = sext i32 %i.0 to i64
+  %arrayidx2 = getelementptr inbounds i32, i32* %B, i64 %idxprom1
+  store i32 %i.0, i32* %arrayidx2, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %Stmt
+  %add = add nsw i32 %i.0, 1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret void
+}