[PATCH] Allow setcc (sext setcc) [0|1] [eq|ne] -> setcc

[Chandler Carruth]

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Comment at: lib/CodeGen/SelectionDAG/TargetLowering.cpp:1204
@@ +1203,3 @@
+// setcc (setcc), [0|1], [eq|ne]  -> setcc
+static SDValue setCCSetCCCombine(const TargetLowering *TLI,
+                                 TargetLowering::DAGCombinerInfo &DCI,
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I would call it 'nestedSetCCCombine'?

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Comment at: lib/CodeGen/SelectionDAG/TargetLowering.cpp:1496
@@ +1495,3 @@
+          return Ret;
+      } else if (N0.getOpcode() == ISD::SIGN_EXTEND) {
+        // setcc (sext (setcc)), [0|1], [eq|ne]  -> setcc
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Why only sign_extend? if zext or anyext can't happen here, it seems worth a comment.

http://reviews.llvm.org/D4600