Assert that we don't RAUW a Constant with a ConstantExpr that contains it.
We already had an assert for foo->RAUW(foo), but not for something like
foo->RAUW(GEP(foo)) and would go in an infinite loop trying to apply
the replacement.
llvm-svn: 208663
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 2ebdb70..9a79e43 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -301,10 +301,45 @@
ST->reinsertValue(this);
}
+#ifndef NDEBUG
+static bool contains(SmallPtrSet<ConstantExpr *, 4> &Cache, ConstantExpr *Expr,
+ Constant *C) {
+ if (!Cache.insert(Expr))
+ return false;
+
+ for (auto &O : Expr->operands()) {
+ if (O == C)
+ return true;
+ auto *CE = dyn_cast<ConstantExpr>(O);
+ if (!CE)
+ continue;
+ if (contains(Cache, CE, C))
+ return true;
+ }
+ return false;
+}
+
+static bool contains(Value *Expr, Value *V) {
+ if (Expr == V)
+ return true;
+
+ auto *C = dyn_cast<Constant>(V);
+ if (!C)
+ return false;
+
+ auto *CE = dyn_cast<ConstantExpr>(Expr);
+ if (!CE)
+ return false;
+
+ SmallPtrSet<ConstantExpr *, 4> Cache;
+ return contains(Cache, CE, C);
+}
+#endif
void Value::replaceAllUsesWith(Value *New) {
assert(New && "Value::replaceAllUsesWith(<null>) is invalid!");
- assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!");
+ assert(!contains(New, this) &&
+ "this->replaceAllUsesWith(expr(this)) is NOT valid!");
assert(New->getType() == getType() &&
"replaceAllUses of value with new value of different type!");