[Attributor] Fix sanitizer for getAssumedMinTrailingZeros()

Author: Shoreshen

llvm/include/llvm/Transforms/IPO/Attributor.h

@@ -5341,6 +5341,8 @@ struct AAPotentialConstantValues
 
   /// Return the minimum trailing zeros of potential constants
   unsigned getAssumedMinTrailingZeros() const {
+    if (!isValidState() || getAssumedSet().empty())
+      return 0;
     unsigned TrailingZeros = getAssumedSet().begin()->getBitWidth() + 1;
     for (const APInt &It : getAssumedSet()) {
       if (It.countTrailingZeros() < TrailingZeros)

llvm/test/lit.cfg.py

@@ -584,7 +584,7 @@ def have_cxx_shared_library():
         print("could not exec llvm-readobj")
         return False
 
-    readobj_out = readobj_cmd.stdout.read().decode("ascii")
+    readobj_out = readobj_cmd.stdout.read().decode("utf-8")
     readobj_cmd.wait()
 
     regex = re.compile(r"(libc\+\+|libstdc\+\+|msvcp).*\.(so|dylib|dll)")