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authorEli Friedman <eli.friedman@gmail.com>2009-05-24 20:32:10 +0000
committerEli Friedman <eli.friedman@gmail.com>2009-05-24 20:32:10 +0000
commitc046c00d0a1f65483a8c69f26c66fc74f5228332 (patch)
tree6e7b5eda823045bb0717cba96abcc22ec6b5990a /lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
parent57f1a4bc40e9103cd41cf541b9d6a73b92f0acba (diff)
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Add a comment which should hopefully make the purpose of this method a
bit clearer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72374 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp')
-rw-r--r--lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp3
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index b6f74aea41..693ac68e30 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -224,6 +224,9 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
}
SDValue VectorLegalizer::PromoteVectorOp(SDValue Op) {
+ // Vector "promotion" is basically just bitcasting and doing the operation
+ // in a different type. For example, x86 promotes ISD::AND on v2i32 to
+ // v1i64.
MVT VT = Op.getValueType();
assert(Op.getNode()->getNumValues() == 1 &&
"Can't promote a vector with multiple results!");