diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 21 | ||||
| -rw-r--r-- | test/CodeGen/X86/2009-07-20-DAGCombineBug.ll | 29 |
2 files changed, 41 insertions, 9 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 4ff2a3a..370054d 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2475,15 +2475,18 @@ SDValue DAGCombiner::visitSHL(SDNode *N) { if (N1C && N0.getOpcode() == ISD::SRL && N0.getOperand(1).getOpcode() == ISD::Constant) { uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); - uint64_t c2 = N1C->getZExtValue(); - SDValue Mask = DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, N0.getOperand(0), - DAG.getConstant(~0ULL << c1, VT)); - if (c2 > c1) - return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mask, - DAG.getConstant(c2-c1, N1.getValueType())); - else - return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Mask, - DAG.getConstant(c1-c2, N1.getValueType())); + if (c1 < VT.getSizeInBits()) { + uint64_t c2 = N1C->getZExtValue(); + SDValue Mask = DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, + N0.getOperand(0), + DAG.getConstant(~0ULL << c1, VT)); + if (c2 > c1) + return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mask, + DAG.getConstant(c2-c1, N1.getValueType())); + else + return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Mask, + DAG.getConstant(c1-c2, N1.getValueType())); + } } // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1)) if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) diff --git a/test/CodeGen/X86/2009-07-20-DAGCombineBug.ll b/test/CodeGen/X86/2009-07-20-DAGCombineBug.ll new file mode 100644 index 0000000..51aa88d --- /dev/null +++ b/test/CodeGen/X86/2009-07-20-DAGCombineBug.ll @@ -0,0 +1,29 @@ +; RUN: llvm-as < %s | llc -march=x86 + +@bsBuff = internal global i32 0 ; <i32*> [#uses=1] +@llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @bsGetUInt32 to i8*)], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0] + +define fastcc i32 @bsGetUInt32() nounwind ssp { +entry: + %bsBuff.promoted44 = load i32* @bsBuff ; <i32> [#uses=1] + %0 = add i32 0, -8 ; <i32> [#uses=1] + %1 = lshr i32 %bsBuff.promoted44, %0 ; <i32> [#uses=1] + %2 = shl i32 %1, 8 ; <i32> [#uses=1] + br label %bb3.i17 + +bb3.i9: ; preds = %bb3.i17 + br i1 false, label %bb2.i16, label %bb1.i15 + +bb1.i15: ; preds = %bb3.i9 + unreachable + +bb2.i16: ; preds = %bb3.i9 + br label %bb3.i17 + +bb3.i17: ; preds = %bb2.i16, %entry + br i1 false, label %bb3.i9, label %bsR.exit18 + +bsR.exit18: ; preds = %bb3.i17 + %3 = or i32 0, %2 ; <i32> [#uses=0] + ret i32 0 +} |