Use Range.getBitWidth()

Signed-off-by: John Lu <[email protected]>

Author: LU-JOHN

llvm/lib/Analysis/ValueTracking.cpp

@@ -429,14 +429,14 @@ void llvm::computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
     ConstantInt *Upper =
         mdconst::extract<ConstantInt>(Ranges.getOperand(2 * i + 1));
     ConstantRange Range(Lower->getValue(), Upper->getValue());
+    // BitWidth must equal the Ranges BitWidth for the correct number of high
+    // bits to be set.
+    assert(BitWidth == Range.getBitWidth() &&
+           "Known bit width must match range bit width!");
 
     // The first CommonPrefixBits of all values in Range are equal.
     unsigned CommonPrefixBits =
         (Range.getUnsignedMax() ^ Range.getUnsignedMin()).countl_zero();
-    // BitWidth must equal the Ranges BitWidth for the correct number of high
-    // bits to be set.
-    assert(BitWidth == Lower->getBitWidth() &&
-           "Known bit width must match range bit width!");
     APInt Mask = APInt::getHighBitsSet(BitWidth, CommonPrefixBits);
     APInt UnsignedMax = Range.getUnsignedMax().zextOrTrunc(BitWidth);
     Known.One &= UnsignedMax & Mask;