diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/R600/AMDGPUISelLowering.cpp | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp index 8440c39c18d..89dab098710 100644 --- a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp +++ b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp @@ -2048,16 +2048,23 @@ SDValue AMDGPUTargetLowering::PerformDAGCombine(SDNode *N, return DAG.getZeroExtendInReg(BitsFrom, DL, SmallVT); } - if (ConstantSDNode *Val = dyn_cast<ConstantSDNode>(N->getOperand(0))) { + if (ConstantSDNode *CVal = dyn_cast<ConstantSDNode>(N->getOperand(0))) { if (Signed) { + // Avoid undefined left shift of a negative in the constant fold. + // TODO: I'm not sure what the behavior of the hardware is, this should + // probably follow that instead. + int32_t Val = CVal->getSExtValue(); + if (Val < 0) + return SDValue(); + return constantFoldBFE<int32_t>(DAG, - Val->getSExtValue(), + Val, OffsetVal, WidthVal); } return constantFoldBFE<uint32_t>(DAG, - Val->getZExtValue(), + CVal->getZExtValue(), OffsetVal, WidthVal); } |
