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-rw-r--r--lib/CodeGen/SelectionDAG/LegalizeDAG.cpp25
1 files changed, 21 insertions, 4 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 27e621f6d8..0f6f3d5915 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1132,10 +1132,27 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
Result = Tmp1;
break;
}
-// case ISD::CTTZ:
-// break;
-// case ISD::CTLZ:
-// break;
+ case ISD::CTTZ:
+ /* This should be used for targets that support ctpop:
+int nlz5(unsigned x) {
+ int pop(unsigned x);
+
+ x = x | (x >> 1);
+ x = x | (x >> 2);
+ x = x | (x >> 4);
+ x = x | (x >> 8);
+ x = x | (x >>16);
+ return ctpop(~x);
+}
+ See also: http://www.hackersdelight.org/HDcode/nlz.cc
+*/
+
+ assert(0 && "Cannot expand this yet!");
+ break;
+ case ISD::CTLZ:
+ // See Also: http://www.hackersdelight.org/HDcode/ntz.cc
+ assert(0 && "Cannot expand this yet!");
+ break;
default:
assert(0 && "Cannot expand this yet!");
break;