Could you please tell me how can I solve the following problem in which I get a strange instruction selection error ("Match failed at index 0" - see below for details).
I have a shufflevector instruction that has as first operand a MaskedGatherSDNode whose index is (in LLVM IR):
%5 = sext <8 x i16> %varVecIndexInnerLoop to <8 x i64>, !dbg !24
%varVecIndexInnerLoop = phi <8 x i16> [ zeroinitializer, %vector.ph ], [ %vecIndexAddRes, %vector.body ]
So the index of the MaskedGatherSDNode is in another basic-block.
My problem is that I try to reuse the index in another Machine SDNode subtract instruction \(because I want to use the same register as in the index\), but then I get the following instruction selection error:
Entered ConnexDAGToDAGISel::Select(): Selecting Node = t45: v8i64 = sign_extend t44, test.c:39:5
Opcode = 157
ConnexDAGToDAGISel::Select(): default case: Opcode = 157
ISEL: Starting pattern match
Initial Opcode index to 0
Match failed at index 0
LLVM ERROR: Cannot select: t45: v8i64 = sign_extend t44, test.c:39:5
t44: v8i16,ch = CopyFromReg t0, Register:v8i16 %6, test.c:39:5
t43: v8i16 = Register %6
In function: Stencil
Can I avoid this error maybe by replicating the index of the MaskedGatherSDNode as a separate node?
Thank you very much,