3 files changed, 12 insertions, 28 deletions
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 2e1caf51b10..4ee92fcfa93 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -149,11 +149,6 @@ static cl::opt<bool>
                            cl::Hidden, cl::init(false), cl::ZeroOrMore,
                            cl::cat(PollyCategory));
 
-static cl::opt<bool> AllowUnsigned("polly-allow-unsigned",
-                                   cl::desc("Allow unsigned expressions"),
-                                   cl::Hidden, cl::init(false), cl::ZeroOrMore,
-                                   cl::cat(PollyCategory));
-
 static cl::opt<bool, true>
     TrackFailures("polly-detect-track-failures",
                   cl::desc("Track failure strings in detecting scop regions"),
@@ -385,13 +380,6 @@ bool ScopDetection::isValidBranch(BasicBlock &BB, BranchInst *BI,
   }
 
   ICmpInst *ICmp = cast<ICmpInst>(Condition);
-  // Unsigned comparisons are not allowed. They trigger overflow problems
-  // in the code generation.
-  //
-  // TODO: This is not sufficient and just hides bugs. However it does pretty
-  //       well.
-  if (ICmp->isUnsigned() && !AllowUnsigned)
-    return invalid<ReportUnsignedCond>(Context, /*Assert=*/true, BI, &BB);
 
   // Are both operands of the ICmp affine?
   if (isa<UndefValue>(ICmp->getOperand(0)) ||
diff --git a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
index 5d5a1a43f8e..25b121bc3ae 100644
--- a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
+++ b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
@@ -196,22 +196,6 @@ bool ReportInvalidCond::classof(const RejectReason *RR) {
 }
 
 //===----------------------------------------------------------------------===//
-// ReportUnsignedCond.
-
-std::string ReportUnsignedCond::getMessage() const {
-  return ("Condition in BB '" + BB->getName()).str() +
-         "' performs a comparision on (not yet supported) unsigned integers.";
-}
-
-std::string ReportUnsignedCond::getEndUserMessage() const {
-  return "Unsupported comparision on unsigned integers encountered";
-}
-
-bool ReportUnsignedCond::classof(const RejectReason *RR) {
-  return RR->getKind() == rrkUnsignedCond;
-}
-
-//===----------------------------------------------------------------------===//
 // ReportUndefOperand.
 
 std::string ReportUndefOperand::getMessage() const {
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 3b8770afa9a..014919634ed 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1317,6 +1317,18 @@ buildConditionSets(ScopStmt &Stmt, Value *Condition, TerminatorInst *TI,
     isl_pw_aff *LHS, *RHS;
     LHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(0), L));
     RHS = Stmt.getPwAff(SE.getSCEVAtScope(ICond->getOperand(1), L));
+
+    if (ICond->isUnsigned()) {
+      // For unsigned comparisons we assumed the signed bit of neither operand
+      // to be set. The comparison is equal to a signed comparison under this
+      // assumption.
+      auto *BB = Stmt.getEntryBlock();
+      S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(LHS)),
+                         TI->getDebugLoc(), AS_ASSUMPTION, BB);
+      S.recordAssumption(UNSIGNED, isl_pw_aff_nonneg_set(isl_pw_aff_copy(RHS)),
+                         TI->getDebugLoc(), AS_ASSUMPTION, BB);
+    }
+
     ConsequenceCondSet =
         buildConditionSet(ICond->getPredicate(), LHS, RHS, Domain);
   }