search for: expandshiftwithknownamountbit

...called. Below is the execution of DAGTypeLegalizer::ExpandIntRes_Shift() using my example showing how ExpandShiftWithUnknownAmountBit gets called. My email is about the logic of this function. if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N->getOperand(1))) { <== False ... } if (ExpandShiftWithKnownAmountBit(N, Lo, Hi)) { <== The call returns False ... } if (N->getOpcode() == ISD::SHL) { <== Branch taken PartsOpc = ISD::SHL_PARTS; } else if (N->getOpcode() == ISD::SRL) { ... } else { ... } if ((Action == TargetLowering::Legal && TLI.isTypeLegal(NVT)) || Action == T...

Hi Javier, > The problem is the implementation of the expansion. Perhaps an example > can help illustrate better. Take the case of a 64-bit integer shifted > left by say 6 bits and is decomposed using 32-bit registers. Because 6 > is less than the 32 (the register size) the resulting low part should be > equal to the source low part shifted left by 6 bits. The current >

Hi Duncan, The problem is the implementation of the expansion. Perhaps an example can help illustrate better. Take the case of a 64-bit integer shifted left by say 6 bits and is decomposed using 32-bit registers. Because 6 is less than the 32 (the register size) the resulting low part should be equal to the source low part shifted left by 6 bits. The current implementation places a zero