Minor speedup for legalize by avoiding some malloc traffic
llvm-svn: 30477
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index df6d604..55b128f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1329,6 +1329,15 @@
if (EVT == VT) return N1; // Not actually extending
break;
}
+ case ISD::EXTRACT_ELEMENT:
+ // EXTRACT_ELEMENT of BUILD_PAIR is often formed while legalize is expanding
+ // 64-bit integers into 32-bit parts. Instead of building the extract of
+ // the BUILD_PAIR, only to have legalize rip it apart, just do it now.
+ if (N2C && N1.getOpcode() == ISD::BUILD_PAIR) {
+ assert((unsigned)N2C->getValue() < 2 && "Bad EXTRACT_ELEMENT!");
+ return N1.getOperand(N2C->getValue());
+ }
+ break;
// FIXME: figure out how to safely handle things like
// int foo(int x) { return 1 << (x & 255); }