SCEV validator: Add workarounds for some common false positives due to the way it handles strings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166872 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 8c2ba6a..806eafa 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -6941,6 +6941,16 @@
}
typedef DenseMap<const Loop *, std::string> VerifyMap;
+
+/// replaceSubString - Replaces all occurences of From in Str with To.
+static void replaceSubString(std::string &Str, StringRef From, StringRef To) {
+ size_t Pos = 0;
+ while ((Pos = Str.find(From, Pos)) != std::string::npos) {
+ Str.replace(Pos, From.size(), To.data(), To.size());
+ Pos += To.size();
+ }
+}
+
/// getLoopBackedgeTakenCounts - Helper method for verifyAnalysis.
static void
getLoopBackedgeTakenCounts(Loop *L, VerifyMap &Map, ScalarEvolution &SE) {
@@ -6951,6 +6961,14 @@
if (S.empty()) {
raw_string_ostream OS(S);
SE.getBackedgeTakenCount(L)->print(OS);
+
+ // false and 0 are semantically equivalent. This can happen in dead loops.
+ replaceSubString(OS.str(), "false", "0");
+ // Remove wrap flags, their use in SCEV is highly fragile.
+ // FIXME: Remove this when SCEV gets smarter about them.
+ replaceSubString(OS.str(), "<nw>", "");
+ replaceSubString(OS.str(), "<nsw>", "");
+ replaceSubString(OS.str(), "<nuw>", "");
}
}
}