[llvm] r305768 - [DAG] Simplify BaseIndexOffset. NFCI.
Nirav Dave via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 19 19:48:39 PDT 2017
Author: niravd
Date: Mon Jun 19 21:48:39 2017
New Revision: 305768
URL: http://llvm.org/viewvc/llvm-project?rev=305768&view=rev
Log:
[DAG] Simplify BaseIndexOffset. NFCI.
Remove tail calls and cleanup codeflow.
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=305768&r1=305767&r2=305768&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Jun 19 21:48:39 2017
@@ -4726,74 +4726,72 @@ struct BaseIndexOffset {
}
/// Parses tree in Ptr for base, index, offset addresses.
- static BaseIndexOffset match(SDValue Ptr, SelectionDAG &DAG,
- int64_t PartialOffset = 0) {
+ static BaseIndexOffset match(SDValue Ptr, SelectionDAG &DAG) {
+
+ SDValue Base = Ptr;
+ SDValue Index = SDValue();
+ int64_t Offset = 0;
bool IsIndexSignExt = false;
- // Split up a folded GlobalAddress+Offset into its component parts.
- if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Ptr))
- if (GA->getOpcode() == ISD::GlobalAddress && GA->getOffset() != 0) {
- return BaseIndexOffset(DAG.getGlobalAddress(GA->getGlobal(),
- SDLoc(GA),
- GA->getValueType(0),
- /*Offset=*/PartialOffset,
- /*isTargetGA=*/false,
- GA->getTargetFlags()),
- SDValue(),
- GA->getOffset(),
- IsIndexSignExt);
- }
+ // (((B + I*M) + O)) + O ...
- // We only can pattern match BASE + INDEX + OFFSET. If Ptr is not an ADD
- // instruction, then it could be just the BASE or everything else we don't
- // know how to handle. Just use Ptr as BASE and give up.
- if (Ptr->getOpcode() != ISD::ADD)
- return BaseIndexOffset(Ptr, SDValue(), PartialOffset, IsIndexSignExt);
-
- // We know that we have at least an ADD instruction. Try to pattern match
- // the simple case of BASE + OFFSET.
- if (isa<ConstantSDNode>(Ptr->getOperand(1))) {
- int64_t Offset = cast<ConstantSDNode>(Ptr->getOperand(1))->getSExtValue();
- return match(Ptr->getOperand(0), DAG, Offset + PartialOffset);
+ //Consume constant adds
+ while (Base->getOpcode() == ISD::ADD &&
+ isa<ConstantSDNode>(Base->getOperand(1))) {
+ int64_t POffset = cast<ConstantSDNode>(Base->getOperand(1))->getSExtValue();
+ Offset += POffset;
+ Base = Base->getOperand(0);
}
- // Inside a loop the current BASE pointer is calculated using an ADD and a
- // MUL instruction. In this case Ptr is the actual BASE pointer.
- // (i64 add (i64 %array_ptr)
- // (i64 mul (i64 %induction_var)
- // (i64 %element_size)))
- if (Ptr->getOperand(1)->getOpcode() == ISD::MUL)
- return BaseIndexOffset(Ptr, SDValue(), PartialOffset, IsIndexSignExt);
-
- // Look at Base + Index + Offset cases.
- SDValue Base = Ptr->getOperand(0);
- SDValue IndexOffset = Ptr->getOperand(1);
-
- // Skip signextends.
- if (IndexOffset->getOpcode() == ISD::SIGN_EXTEND) {
- IndexOffset = IndexOffset->getOperand(0);
- IsIndexSignExt = true;
- }
+ // Split up a folded GlobalAddress+Offset into its component parts.
+ if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Base))
+ if (GA->getOpcode() == ISD::GlobalAddress && GA->getOffset() != 0) {
+ Base = DAG.getGlobalAddress(GA->getGlobal(),
+ SDLoc(GA),
+ GA->getValueType(0),
+ /*Offset*/ 0,
+ /*isTargetGA=*/false,
+ GA->getTargetFlags());
+ Offset += GA->getOffset();
+ return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
+ }
- // Either the case of Base + Index (no offset) or something else.
- if (IndexOffset->getOpcode() != ISD::ADD)
- return BaseIndexOffset(Base, IndexOffset, PartialOffset, IsIndexSignExt);
-
- // Now we have the case of Base + Index + offset.
- SDValue Index = IndexOffset->getOperand(0);
- SDValue Offset = IndexOffset->getOperand(1);
+ if (Base->getOpcode() == ISD::ADD) {
+ // TODO: The following code appears to be needless as it just
+ // bails on some Ptrs early, reducing the cases where we
+ // find equivalence. We should be able to remove this.
+ // Inside a loop the current BASE pointer is calculated using an ADD and a
+ // MUL instruction. In this case Base is the actual BASE pointer.
+ // (i64 add (i64 %array_ptr)
+ // (i64 mul (i64 %induction_var)
+ // (i64 %element_size)))
+ if (Base->getOperand(1)->getOpcode() == ISD::MUL)
+ return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
+
+ // Look at Base + Index + Offset cases.
+ Index = Base->getOperand(1);
+ SDValue PotentialBase = Base->getOperand(0);
+
+ // Skip signextends.
+ if (Index->getOpcode() == ISD::SIGN_EXTEND) {
+ Index = Index->getOperand(0);
+ IsIndexSignExt = true;
+ }
- if (!isa<ConstantSDNode>(Offset))
- return BaseIndexOffset(Ptr, SDValue(), PartialOffset, IsIndexSignExt);
+ // Check if Index Offset pattern
+ if (Index->getOpcode() != ISD::ADD ||
+ !isa<ConstantSDNode>(Index->getOperand(1)))
+ return BaseIndexOffset(PotentialBase, Index, Offset, IsIndexSignExt);
- // Ignore signextends.
- if (Index->getOpcode() == ISD::SIGN_EXTEND) {
+ Offset += cast<ConstantSDNode>(Index->getOperand(1))->getSExtValue();
Index = Index->getOperand(0);
- IsIndexSignExt = true;
- } else IsIndexSignExt = false;
-
- int64_t Off = cast<ConstantSDNode>(Offset)->getSExtValue();
- return BaseIndexOffset(Base, Index, Off + PartialOffset, IsIndexSignExt);
+ if (Index->getOpcode() == ISD::SIGN_EXTEND) {
+ Index = Index->getOperand(0);
+ IsIndexSignExt = true;
+ } else IsIndexSignExt = false;
+ Base = PotentialBase;
+ }
+ return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
}
};
} // namespace
More information about the llvm-commits
mailing list