maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[DAG] Generalize (sra (trunc (sra x, c1)), c2) -> (trunc (sra x, c1 + c2)) constant folding 

Remove local (uniform) constant folding and rely on getNode() to perform it

Minor cleanup step toward adding non-uniform shift amount support
This commit is contained in:
Simon Pilgrim 2022-05-26 14:05:00 +01:00
parent d4d28f2ace
commit f366acdbf6
1 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -9286,8 +9286,10 @@ SDValue DAGCombiner::visitSRA(SDNode *N) {
unsigned TruncBits = LargeVT.getScalarSizeInBits() - OpSizeInBits;
if (LargeShift->getAPIntValue() == TruncBits) {
SDLoc DL(N);
SDValue Amt = DAG.getConstant(N1C->getZExtValue() + TruncBits, DL,
getShiftAmountTy(LargeVT));
EVT LargeShiftVT = getShiftAmountTy(LargeVT);
SDValue Amt = DAG.getZExtOrTrunc(N1, DL, LargeShiftVT);
Amt = DAG.getNode(ISD::ADD, DL, LargeShiftVT, Amt,
DAG.getConstant(TruncBits, DL, LargeShiftVT));
SDValue SRA =
DAG.getNode(ISD::SRA, DL, LargeVT, N0Op0.getOperand(0), Amt);
return DAG.getNode(ISD::TRUNCATE, DL, VT, SRA);