diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86ISelDAGToDAG.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp index 32ad262e558..a0ef4b61263 100644 --- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp +++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp @@ -2590,7 +2590,14 @@ bool X86DAGToDAGISel::matchBEXTRFromAnd(SDNode *Node) { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); - if (!Subtarget->hasBMI() && !Subtarget->hasTBM()) + // If we have TBM we can use an immediate for the control. If we have BMI + // we should only do this if the BEXTR instruction is implemented well. + // Otherwise moving the control into a register makes this more costly. + // TODO: Maybe load folding, greater than 32-bit masks, or a guarantee of LICM + // hoisting the move immediate would make it worthwhile with a less optimal + // BEXTR? + if (!Subtarget->hasTBM() && + !(Subtarget->hasBMI() && Subtarget->hasFastBEXTR())) return false; // Must have a shift right. |
