Simplify isHighOnes().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35211 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Zhou Sheng 2007-03-20 12:49:06 +00:00
parent 07073e5f70
commit 2cde46cb66

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@ -3491,15 +3491,7 @@ static bool isLowOnes(const ConstantInt *CI) {
// isHighOnes - Return true if the constant is of the form 1+0+.
// This is the same as lowones(~X).
static bool isHighOnes(const ConstantInt *CI) {
if (CI->getValue() == 0) return false; // 0's does not match "1+"
APInt V(~CI->getValue());
// There won't be bits set in parts that the type doesn't contain.
V &= APInt::getAllOnesValue(CI->getType()->getBitWidth());
APInt U(V+1); // If it is low ones, this should be a power of two.
return (U!=0) && (V!=0) && (U & V) == 0;
return (~CI->getValue() + 1).isPowerOf2();
}
/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits