Changes in directory llvm/lib/CodeGen/SelectionDAG:
SelectionDAG.cpp updated: 1.339 -> 1.340
---
Log message:
Fold extract_element(cst) to cst
---
Diffs of the changes: (+8 -2)
SelectionDAG.cpp | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.339
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.340
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.339 Mon Sep 18
23:51:23 2006
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Tue Sep 19 00:02:39 2006
@@ -1330,12 +1330,18 @@
break;
}
case ISD::EXTRACT_ELEMENT:
+ assert(N2C && (unsigned)N2C->getValue() < 2 && "Bad 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!");
+ if (N1.getOpcode() == ISD::BUILD_PAIR)
return N1.getOperand(N2C->getValue());
+
+ // EXTRACT_ELEMENT of a constant int is also very common.
+ if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N1)) {
+ unsigned Shift = MVT::getSizeInBits(VT) * N2C->getValue();
+ return getConstant(C->getValue() >> Shift, VT);
}
break;
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