diff options
| author | Dan Gohman <gohman@apple.com> | 2010-04-21 00:19:28 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2010-04-21 00:19:28 +0000 |
| commit | bc7588eb6882466fe3cd2e36bfb3d01e4ce23faa (patch) | |
| tree | 1ad414dcdda974caea3f61780d97e59c0cca0610 /lib/CodeGen/SelectionDAG/SelectionDAG.cpp | |
| parent | d6139425f5f5c303d5ae6a2202fb40a8f6dde9a6 (diff) | |
Add another variant of this test which found a place where
CodeGen's ComputeMaskedBits was being over-conservative when computing
bits for an ADD.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101963 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAG.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 13f69c4e81..5031170946 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1917,7 +1917,8 @@ void SelectionDAG::ComputeMaskedBits(SDValue Op, const APInt &Mask, // Output known-0 bits are known if clear or set in both the low clear bits // common to both LHS & RHS. For example, 8+(X<<3) is known to have the // low 3 bits clear. - APInt Mask2 = APInt::getLowBitsSet(BitWidth, Mask.countTrailingOnes()); + APInt Mask2 = APInt::getLowBitsSet(BitWidth, + BitWidth - Mask.countLeadingZeros()); ComputeMaskedBits(Op.getOperand(0), Mask2, KnownZero2, KnownOne2, Depth+1); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); unsigned KnownZeroOut = KnownZero2.countTrailingOnes(); |