Implement carry for subtract/add for mips16

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166755 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/Mips16InstrInfo.td

@@ -194,6 +194,10 @@ class FRR16_ins<bits<5> f, string asmstr, InstrItinClass itin> :
         !strconcat(asmstr, "\t$rx, $ry"), [], itin> {
 }
 
+class FRRTR16_ins<bits<5> f, string asmstr, InstrItinClass itin> :
+  FRR16<f, (outs CPU16Regs:$rz), (ins CPU16Regs:$rx, CPU16Regs:$ry),
+        !strconcat(asmstr, "\t$rx, $ry\n\tmove\t$rz, $$t8"), [], itin> ;
+
 //
 // maybe refactor but need a $zero as a dummy first parameter
 //
@@ -816,6 +820,9 @@ def SltCCRxRy16: FCCRR16_ins<0b00010, "slt", IIAlu>;
 // Purpose: Set on Less Than Unsigned
 // To record the result of an unsigned less-than comparison.
 //
+def SltuRxRyRz16: FRRTR16_ins<0b00011, "sltu", IIAlu> {
+  let isCodeGenOnly=1;
+}
 
 
 def SltuCCRxRy16: FCCRR16_ins<0b00011, "sltu", IIAlu>;
@@ -976,6 +983,14 @@ def : Mips16Pat<(i32 imm:$imm),
                 (OrRxRxRy16 (SllX16 (LiRxImmX16 (HI16 imm:$imm)), 16),
                 (LiRxImmX16 (LO16 imm:$imm)))>;
 
+// Carry MipsPatterns
+def : Mips16Pat<(subc CPU16Regs:$lhs, CPU16Regs:$rhs),
+                (SubuRxRyRz16 CPU16Regs:$lhs, CPU16Regs:$rhs)>;
+def : Mips16Pat<(addc CPU16Regs:$lhs, CPU16Regs:$rhs),
+                (AdduRxRyRz16 CPU16Regs:$lhs, CPU16Regs:$rhs)>;
+def : Mips16Pat<(addc  CPU16Regs:$src, immSExt16:$imm),
+                (AddiuRxRxImmX16 CPU16Regs:$src, imm:$imm)>;
+
 //
 // Some branch conditional patterns are not generated by llvm at this time.
 // Some are for seemingly arbitrary reasons not used: i.e. with signed number

lib/Target/Mips/MipsISelDAGToDAG.cpp

@@ -413,6 +413,7 @@ SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
 
   case ISD::SUBE:
   case ISD::ADDE: {
+    bool inMips16Mode = Subtarget.inMips16Mode();
     SDValue InFlag = Node->getOperand(2), CmpLHS;
     unsigned Opc = InFlag.getOpcode(); (void)Opc;
     assert(((Opc == ISD::ADDC || Opc == ISD::ADDE) ||
@@ -422,10 +423,16 @@ SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
     unsigned MOp;
     if (Opcode == ISD::ADDE) {
       CmpLHS = InFlag.getValue(0);
-      MOp = Mips::ADDu;
+      if (inMips16Mode)
+        MOp = Mips::AdduRxRyRz16;
+      else
+        MOp = Mips::ADDu;
     } else {
       CmpLHS = InFlag.getOperand(0);
-      MOp = Mips::SUBu;
+      if (inMips16Mode)
+        MOp = Mips::SubuRxRyRz16;
+      else
+        MOp = Mips::SUBu;
     }
 
     SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };
@@ -434,8 +441,11 @@ SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
     SDValue RHS = Node->getOperand(1);
 
     EVT VT = LHS.getValueType();
-    SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, dl, VT, Ops, 2);
+
-    SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, dl, VT,
+    unsigned Sltu_op = inMips16Mode? Mips::SltuRxRyRz16: Mips::SLTu;
+    SDNode *Carry = CurDAG->getMachineNode(Sltu_op, dl, VT, Ops, 2);
+    unsigned Addu_op = inMips16Mode? Mips::AdduRxRyRz16 : Mips::ADDu;
+    SDNode *AddCarry = CurDAG->getMachineNode(Addu_op, dl, VT,
                                               SDValue(Carry,0), RHS);
 
     return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue,

test/CodeGen/Mips/llcarry.ll

@@ -0,0 +1,51 @@
+; RUN: llc  -march=mipsel -mcpu=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16
+
+@i = global i64 4294967295, align 8
+@j = global i64 15, align 8
+@ii = global i64 4294967295, align 8
+@k = common global i64 0, align 8
+@l = common global i64 0, align 8
+@m = common global i64 0, align 8
+
+define void @test1() nounwind {
+entry:
+  %0 = load i64* @i, align 8
+  %1 = load i64* @j, align 8
+  %add = add nsw i64 %1, %0
+  store i64 %add, i64* @k, align 8
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+; 16:	sltu	${{[0-9]+}}, ${{[0-9]+}}
+; 16:	move	${{[0-9]+}}, $t8
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+  ret void
+}
+
+define void @test2() nounwind {
+entry:
+  %0 = load i64* @i, align 8
+  %1 = load i64* @j, align 8
+  %sub = sub nsw i64 %0, %1
+; 16:	subu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+; 16:	sltu	${{[0-9]+}}, ${{[0-9]+}}
+; 16:	move	${{[0-9]+}}, $t8
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+; 16:	subu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+  store i64 %sub, i64* @l, align 8
+  ret void
+}
+
+define void @test3() nounwind {
+entry:
+  %0 = load i64* @ii, align 8
+  %add = add nsw i64 %0, 15
+; 16:	addiu	${{[0-9]+}}, 15
+; 16:	sltu	${{[0-9]+}}, ${{[0-9]+}}
+; 16:	move	${{[0-9]+}}, $t8
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+; 16:	addu	${{[0-9]+}}, ${{[0-9]+}}, ${{[0-9]+}}
+  store i64 %add, i64* @m, align 8
+  ret void
+}
+
+