Actually, disable this code for now. More analysis and improvements to
the X86 backend are needed before this should be enabled by default.
llvm-svn: 44657
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 918db38..ba3c0ac 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2134,6 +2134,12 @@
/// visitShiftByConstant - Handle transforms common to the three shifts, when
/// the shift amount is a constant.
SDOperand DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) {
+ // FIXME: disable this for now. This pessimizes some common cases like:
+ //
+ //void foo(int *X, int i) { X[i & 1235] = 1; }
+ //int bar(int *X, int i) { return X[i & 255]; }
+ return SDOperand();
+
SDNode *LHS = N->getOperand(0).Val;
if (!LHS->hasOneUse()) return SDOperand();