[IslNodeBuilder] Move run-time check generation to NodeBuilder [NFC]

This improves the structure of the code and allows us to reuse the runtime
code generation in the PPCGCodeGeneration.

llvm-svn: 278017

polly/include/polly/CodeGen/IslNodeBuilder.h

@@ -66,6 +66,20 @@ public:
   virtual ~IslNodeBuilder() {}
 
   void addParameters(__isl_take isl_set *Context);
+
+  /// @brief Generate code that evaluates @p Condition at run-time.
+  ///
+  /// This function is typically called to generate the LLVM-IR for the
+  /// run-time condition of the scop, that verifies that all the optimistic
+  /// assumptions we have taken during scop modeling and transformation
+  /// hold at run-time.
+  ///
+  /// @param Condition The condition to evaluate
+  ///
+  /// @result An llvm::Value that is true if the condition holds and false
+  ///         otherwise.
+  Value *createRTC(isl_ast_expr *Condition);
+
   void create(__isl_take isl_ast_node *Node);
 
   /// @brief Allocate memory for all new arrays created by Polly.

polly/lib/CodeGen/CodeGeneration.cpp

@@ -66,19 +66,6 @@ public:
   RegionInfo *RI;
   ///}
 
-  /// @brief Build the runtime condition.
-  ///
-  /// Build the condition that evaluates at run-time to true iff all
-  /// assumptions taken for the SCoP hold, and to false otherwise.
-  ///
-  /// @return A value evaluating to true/false if execution is save/unsafe.
-  Value *buildRTC(PollyIRBuilder &Builder, IslExprBuilder &ExprBuilder) {
-    Value *RTC = ExprBuilder.create(AI->getRunCondition());
-    if (!RTC->getType()->isIntegerTy(1))
-      RTC = Builder.CreateIsNotNull(RTC);
-    return RTC;
-  }
-
   void verifyGeneratedFunction(Scop &S, Function &F) {
     if (!verifyFunction(F, &errs()) || !Verify)
       return;
@@ -147,7 +134,6 @@ public:
     PollyIRBuilder Builder = createPollyIRBuilder(EnteringBB, Annotator);
 
     IslNodeBuilder NodeBuilder(Builder, Annotator, this, *DL, *LI, *SE, *DT, S);
-    IslExprBuilder &ExprBuilder = NodeBuilder.getExprBuilder();
 
     // Only build the run-time condition and parameters _after_ having
     // introduced the conditional branch. This is important as the conditional
@@ -189,15 +175,8 @@ public:
       isl_ast_node_free(AstRoot);
     } else {
       NodeBuilder.allocateNewArrays();
-
       NodeBuilder.addParameters(S.getContext());
-
-      ExprBuilder.setTrackOverflow(true);
-      Value *RTC = buildRTC(Builder, ExprBuilder);
-      Value *OverflowHappened = Builder.CreateNot(
-          ExprBuilder.getOverflowState(), "polly.rtc.overflown");
-      RTC = Builder.CreateAnd(RTC, OverflowHappened, "polly.rtc.result");
-      ExprBuilder.setTrackOverflow(false);
+      Value *RTC = NodeBuilder.createRTC(AI->getRunCondition());
 
       Builder.GetInsertBlock()->getTerminator()->setOperand(0, RTC);
       Builder.SetInsertPoint(&StartBlock->front());

polly/lib/CodeGen/IslNodeBuilder.cpp

@@ -1239,3 +1239,20 @@ Value *IslNodeBuilder::generateSCEV(const SCEV *Expr) {
   return expandCodeFor(S, SE, DL, "polly", Expr, Expr->getType(),
                        InsertLocation, &ValueMap);
 }
+
+/// The AST expression we generate to perform the run-time check assumes
+/// computations on integer types of infinite size. As we only use 64-bit
+/// arithmetic we check for overflows, in case of which we set the result
+/// of this run-time check to false to be cosnservatively correct,
+Value *IslNodeBuilder::createRTC(isl_ast_expr *Condition) {
+  auto ExprBuilder = getExprBuilder();
+  ExprBuilder.setTrackOverflow(true);
+  Value *RTC = ExprBuilder.create(Condition);
+  if (!RTC->getType()->isIntegerTy(1))
+    RTC = Builder.CreateIsNotNull(RTC);
+  Value *OverflowHappened =
+      Builder.CreateNot(ExprBuilder.getOverflowState(), "polly.rtc.overflown");
+  RTC = Builder.CreateAnd(RTC, OverflowHappened, "polly.rtc.result");
+  ExprBuilder.setTrackOverflow(false);
+  return RTC;
+}