From: Craig Topper <craig.topper@gmail.com>
Date: Sat, 10 Oct 2015 18:54:26 +0000 (+0000)
Subject: In isUIntN, make sure N is less than 64 before using in a shift to avoid undefined... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=41f6283c479aeff95296bae207d6ba3e717f1662

In isUIntN, make sure N is less than 64 before using in a shift to avoid undefined behavior. Also change it to use the same formula as the template version which I think results in less math in compiled code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249951 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h
index 71b22b0f2fc..2c515bbd242 100644
--- a/include/llvm/Support/MathExtras.h
+++ b/include/llvm/Support/MathExtras.h
@@ -313,7 +313,7 @@ inline bool isShiftedUInt(uint64_t x) {
 /// isUIntN - Checks if an unsigned integer fits into the given (dynamic)
 /// bit width.
 inline bool isUIntN(unsigned N, uint64_t x) {
-  return x == (x & (~0ULL >> (64 - N)));
+  return N >= 64 || x < (UINT64_C(1)<<(N));
 }
 
 /// isIntN - Checks if an signed integer fits into the given (dynamic)