diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 918db3835308..ba3c0ac33dcb 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2134,6 +2134,12 @@ SDOperand DAGCombiner::visitXOR(SDNode *N) { /// 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(); diff --git a/llvm/test/CodeGen/X86/shift-combine.ll b/llvm/test/CodeGen/X86/shift-combine.ll index 543bb2237875..c8df5b020800 100644 --- a/llvm/test/CodeGen/X86/shift-combine.ll +++ b/llvm/test/CodeGen/X86/shift-combine.ll @@ -1,4 +1,5 @@ ; RUN: llvm-as < %s | llc | not grep shrl +; XFAIL: * target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" target triple = "i686-apple-darwin8"