AArch64: Implement missed conditional compare sequences.

Summary:
This is an extension to the existing implementation of r242436 which
restricts to only select inputs. This version fixes missed opportunities
in pr26084 by attempting to lower conditional compare sequences of
and/or trees with setcc leafs. This will additionaly handle the case
when a tree with select input is not a conjunction-disjunction tree
but some of the sub trees are conjunction-disjunction trees.

Reviewers: jmolloy, t.p.northover, mcrosier, MatzeB

Subscribers: mcrosier, llvm-commits, junbuml, haicheng, mssimpso, gberry

Differential Revision: http://reviews.llvm.org/D16291

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259387 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6323a4b..be306c0 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1721,7 +1721,7 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
     return SDValue(N, 0);
 
   // fold (a+b) -> (a|b) iff a and b share no bits.
-  if ((!LegalOperations || TLI.isOperationLegal(ISD::OR, VT)) &&
+  if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::OR, VT)) &&
       VT.isInteger() && !VT.isVector() && DAG.haveNoCommonBitsSet(N0, N1))
     return DAG.getNode(ISD::OR, SDLoc(N), VT, N0, N1);
 
@@ -6363,7 +6363,7 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
       isa<LoadSDNode>(N0.getOperand(0)) &&
       N0.getOperand(1).getOpcode() == ISD::Constant &&
       TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, N0.getValueType()) &&
-      (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) {
+      (!LegalOperations && TLI.isOperationLegalOrCustom(N0.getOpcode(), VT))) {
     LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0));
     if (LN0->getExtensionType() != ISD::SEXTLOAD && LN0->isUnindexed()) {
       bool DoXform = true;

diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index 644aa3d..2be5f3c 100644 (file)
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -144,6 +144,16 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
   setOperationAction(ISD::XOR, MVT::i32, Custom);
   setOperationAction(ISD::XOR, MVT::i64, Custom);
 
+  // Custom lowering hooks are needed for OR
+  // to fold it into CCMP.
+  setOperationAction(ISD::OR, MVT::i32, Custom);
+  setOperationAction(ISD::OR, MVT::i64, Custom);
+
+  // Custom lowering hooks are needed for AND
+  // to fold it into CCMP.
+  setOperationAction(ISD::AND, MVT::i32, Custom);
+  setOperationAction(ISD::AND, MVT::i64, Custom);
+
   // Virtually no operation on f128 is legal, but LLVM can't expand them when
   // there's a valid register class, so we need custom operations in most cases.
   setOperationAction(ISD::FABS, MVT::f128, Expand);
@@ -1597,6 +1607,27 @@ static SDValue getAArch64Cmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
   return Cmp;
 }
 
+// Attempt to form conditional compare sequences for and/or trees
+// with setcc leafs.
+static SDValue tryLowerToAArch64Cmp(SDValue Op, SelectionDAG &DAG) {
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  if ((LHS.getOpcode() != ISD::SETCC) || (RHS.getOpcode() != ISD::SETCC))
+    return Op;
+
+  bool CanNegate;
+  if (!isConjunctionDisjunctionTree(Op, CanNegate))
+    return SDValue();
+
+  EVT VT = Op.getValueType();
+  SDLoc DL(Op);
+  SDValue TVal = DAG.getConstant(1, DL, VT);
+  SDValue FVal = DAG.getConstant(0, DL, VT);
+  SDValue CCVal;
+  SDValue Cmp = getAArch64Cmp(Op, FVal, ISD::SETEQ, CCVal, DAG, DL);
+  return DAG.getNode(AArch64ISD::CSEL, DL, VT, FVal, TVal, CCVal, Cmp);
+}
+
 static std::pair<SDValue, SDValue>
 getAArch64XALUOOp(AArch64CC::CondCode &CC, SDValue Op, SelectionDAG &DAG) {
   assert((Op.getValueType() == MVT::i32 || Op.getValueType() == MVT::i64) &&
@@ -1718,6 +1749,18 @@ SDValue AArch64TargetLowering::LowerF128Call(SDValue Op, SelectionDAG &DAG,
   return makeLibCall(DAG, Call, MVT::f128, Ops, false, SDLoc(Op)).first;
 }
 
+SDValue AArch64TargetLowering::LowerAND(SDValue Op, SelectionDAG &DAG) const {
+  if (Op.getValueType().isVector())
+    return LowerVectorAND(Op, DAG);
+  return tryLowerToAArch64Cmp(Op, DAG);
+}
+
+SDValue AArch64TargetLowering::LowerOR(SDValue Op, SelectionDAG &DAG) const {
+  if (Op.getValueType().isVector())
+    return LowerVectorOR(Op, DAG);
+  return tryLowerToAArch64Cmp(Op, DAG);
+}
+
 static SDValue LowerXOR(SDValue Op, SelectionDAG &DAG) {
   SDValue Sel = Op.getOperand(0);
   SDValue Other = Op.getOperand(1);
@@ -2372,9 +2415,9 @@ SDValue AArch64TargetLowering::LowerOperation(SDValue Op,
   case ISD::FCOPYSIGN:
     return LowerFCOPYSIGN(Op, DAG);
   case ISD::AND:
-    return LowerVectorAND(Op, DAG);
+    return LowerAND(Op, DAG);
   case ISD::OR:
-    return LowerVectorOR(Op, DAG);
+    return LowerOR(Op, DAG);
   case ISD::XOR:
     return LowerXOR(Op, DAG);
   case ISD::PREFETCH:

diff --git a/lib/Target/AArch64/AArch64ISelLowering.h b/lib/Target/AArch64/AArch64ISelLowering.h
index e99616c..20c468e 100644 (file)
--- a/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/lib/Target/AArch64/AArch64ISelLowering.h
@@ -488,6 +488,8 @@ private:
   SDValue LowerCTPOP(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerF128Call(SDValue Op, SelectionDAG &DAG,
                         RTLIB::Libcall Call) const;
+  SDValue LowerAND(SDValue Op, SelectionDAG &DAG) const;
+  SDValue LowerOR(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerFP_EXTEND(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerFP_ROUND(SDValue Op, SelectionDAG &DAG) const;

diff --git a/test/CodeGen/AArch64/arm64-ccmp.ll b/test/CodeGen/AArch64/arm64-ccmp.ll
index 767df74..c6062d3 100644 (file)
--- a/test/CodeGen/AArch64/arm64-ccmp.ll
+++ b/test/CodeGen/AArch64/arm64-ccmp.ll
@@ -371,21 +371,76 @@ define i32 @select_andor(i32 %v1, i32 %v2, i32 %v3) {
   ret i32 %sel
 }
 
-; CHECK-LABEL: select_noccmp1
-define i64 @select_noccmp1(i64 %v1, i64 %v2, i64 %v3, i64 %r) {
-; CHECK: cmp x0, #0
-; CHECK-NEXT: cset [[REG0:w[0-9]+]], lt
-; CHECK-NEXT: cmp x0, #13
-; CHECK-NOT: ccmp
+; CHECK-LABEL: single_noselect
+define i32 @single_noselect(i32 %A, i32 %B) #0 {
+; CHECK: cmp w1, #1
+; CHECK-NEXT: ccmp w0, #1, #8, ge
+; CHECK-NEXT: cset w0, lt
+; CHECK-NEXT: ret
+  %notlhs = icmp slt i32 %A, 1
+  %notrhs = icmp slt i32 %B, 1
+  %lnot = or i1 %notlhs, %notrhs
+  %conv = zext i1 %lnot to i32
+  ret i32 %conv
+}
+
+; CHECK-LABEL: single_and_ext
+define i32 @single_and_ext(i32 %A, i32 %B, i32 %C) #0 {
+; CHECK: cmp w1, #2
+; CHECK-NEXT: ccmp w0, #4, #0, lt
+; CHECK-NEXT: cinc w0, w2, lt
+; CHECK-NEXT: ret
+  %cmp = icmp slt i32 %A, 4
+  %cmp1 = icmp slt i32 %B, 2
+  %and1 = and i1 %cmp, %cmp1
+  %conv = zext i1 %and1 to i32
+  %add = add nsw i32 %conv, %C
+  ret i32 %add
+}
+
+; CHECK-LABEL: single_noselect_phi
+define i32 @single_noselect_phi(i32 %A, i32 %B, i32 %C) #0 {
+; CHECK: cmp w1, #0
+; CHECK-NEXT: ccmp w0, #0, #4, gt
 ; CHECK-NEXT: cset [[REG1:w[0-9]+]], gt
-; CHECK-NEXT: cmp x2, #2
+; CHECK-NEXT: cmp w1, #2
+; CHECK-NEXT: ccmp w0, #4, #8, ge
 ; CHECK-NEXT: cset [[REG2:w[0-9]+]], lt
+; CHECK-NEXT: cmp w2, #0
+; CHECK-NEXT: csel w0, [[REG1]], [[REG2]], eq
+; CHECK-NEXT: ret
+entry:
+  %tobool = icmp eq i32 %C, 0
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:                                          ; preds = %entry
+  %cmp = icmp slt i32 %A, 4
+  %cmp1 = icmp slt i32 %B, 2
+  %0 = or i1 %cmp, %cmp1
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %cmp2 = icmp sgt i32 %A, 0
+  %cmp3 = icmp sgt i32 %B, 0
+  %1 = and i1 %cmp2, %cmp3
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %b.0.in = phi i1 [ %0, %if.then ], [ %1, %if.else ]
+  %conv = zext i1 %b.0.in to i32
+  ret i32 %conv
+}
+
+; CHECK-LABEL: select_noccmp1
+define i64 @select_noccmp1(i64 %v1, i64 %v2, i64 %v3, i64 %r) {
+; CHECK: cmp x0, #13
+; CHECK-NEXT: ccmp x0, #0, #0, gt
+; CHECK-NEXT: cset [[REG1:w[0-9]+]], lt
 ; CHECK-NEXT: cmp x2, #4
-; CHECK-NEXT: cset [[REG3:w[0-9]+]], gt
-; CHECK-NEXT: and [[REG4:w[0-9]+]], [[REG0]], [[REG1]]
-; CHECK-NEXT: and [[REG5:w[0-9]+]], [[REG2]], [[REG3]]
-; CHECK-NEXT: orr [[REG6:w[0-9]+]], [[REG4]], [[REG5]]
-; CHECK-NEXT: cmp [[REG6]], #0
+; CHECK-NEXT: ccmp x2, #2, #0, gt
+; CHECK-NEXT: cset [[REG2:w[0-9]+]], lt
+; CHECK-NEXT: orr [[REG3:w[0-9]+]], [[REG1]], [[REG2]]
+; CHECK-NEXT: cmp [[REG3]], #0
 ; CHECK-NEXT: csel x0, xzr, x3, ne
 ; CHECK-NEXT: ret
   %c0 = icmp slt i64 %v1, 0