Use the original no-wrap flags for normalized AddRecs

llvm-svn: 235822

2 files changed, 9 insertions, 4 deletions

diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 59bf345cd6f2..2caab15adfa8 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -214,6 +214,8 @@ __isl_give isl_pw_aff *
 SCEVAffinator::visitAddRecExpr(const SCEVAddRecExpr *Expr) {
   assert(Expr->isAffine() && "Only affine AddRecurrences allowed");
 
+  auto Flags = Expr->getNoWrapFlags();
+
   // Directly generate isl_pw_aff for Expr if 'start' is zero.
   if (Expr->getStart()->isZero()) {
     assert(S->getRegion().contains(Expr->getLoop()) &&
@@ -236,10 +238,13 @@ SCEVAffinator::visitAddRecExpr(const SCEVAddRecExpr *Expr) {
 
   // Translate AddRecExpr from '{start, +, inc}' into 'start + {0, +, inc}'
   // if 'start' is not zero.
+  // TODO: Using the original SCEV no-wrap flags is not always safe, however
+  //       as our code generation is reordering the expression anyway it doesn't
+  //       really matter.
   ScalarEvolution &SE = *S->getSE();
-  const SCEV *ZeroStartExpr = SE.getAddRecExpr(
-      SE.getConstant(Expr->getStart()->getType(), 0),
-      Expr->getStepRecurrence(SE), Expr->getLoop(), SCEV::FlagAnyWrap);
+  const SCEV *ZeroStartExpr =
+      SE.getAddRecExpr(SE.getConstant(Expr->getStart()->getType(), 0),
+                       Expr->getStepRecurrence(SE), Expr->getLoop(), Flags);
 
   isl_pw_aff *ZeroStartResult = visit(ZeroStartExpr);
   isl_pw_aff *Start = visit(Expr->getStart());
diff --git a/polly/lib/Support/SCEVValidator.cpp b/polly/lib/Support/SCEVValidator.cpp
index 1cfbd66d8521..80c2249769a0 100644
--- a/polly/lib/Support/SCEVValidator.cpp
+++ b/polly/lib/Support/SCEVValidator.cpp
@@ -287,7 +287,7 @@ public:
     // if 'start' is not zero.
     const SCEV *ZeroStartExpr = SE.getAddRecExpr(
         SE.getConstant(Expr->getStart()->getType(), 0),
-        Expr->getStepRecurrence(SE), Expr->getLoop(), SCEV::FlagAnyWrap);
+        Expr->getStepRecurrence(SE), Expr->getLoop(), Expr->getNoWrapFlags());
 
     ValidatorResult ZeroStartResult =
         ValidatorResult(SCEVType::PARAM, ZeroStartExpr);