Fold zext_inreg(zextload), likewise for sext's
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21204 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 7cf8914..6b94adf 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1101,6 +1101,12 @@
return N1;
}
+ // If we are (zero|sign) extending a [zs]extload, return just the load.
+ if ((N1.getOpcode() == ISD::ZEXTLOAD && Opcode == ISD::ZERO_EXTEND_INREG) ||
+ (N1.getOpcode() == ISD::SEXTLOAD && Opcode == ISD::SIGN_EXTEND_INREG))
+ if (cast<MVTSDNode>(N1)->getExtraValueType() <= EVT)
+ return N1;
+
// If we are extending the result of a setcc, and we already know the
// contents of the top bits, eliminate the extension.
if (N1.getOpcode() == ISD::SETCC)