[Hexagon] Pick a dot-old instruction that matches the architecture

llvm-svn: 297031

3 files changed, 25 insertions, 4 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
index ee49a080435..b265a883da5 100644
--- a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
@@ -3563,10 +3563,31 @@ int HexagonInstrInfo::getDotNewPredOp(const MachineInstr &MI,
   llvm_unreachable(nullptr);
 }
 
-int HexagonInstrInfo::getDotOldOp(const int opc) const {
-  int NewOp = opc;
+int HexagonInstrInfo::getDotOldOp(const MachineInstr &MI) const {
+  int NewOp = MI.getOpcode();
   if (isPredicated(NewOp) && isPredicatedNew(NewOp)) { // Get predicate old form
     NewOp = Hexagon::getPredOldOpcode(NewOp);
+    const MachineFunction &MF = *MI.getParent()->getParent();
+    const HexagonSubtarget &HST = MF.getSubtarget<HexagonSubtarget>();
+    // All Hexagon architectures have prediction bits on dot-new branches,
+    // but only Hexagon V60+ has prediction bits on dot-old ones. Make sure
+    // to pick the right opcode when converting back to dot-old.
+    if (!HST.getFeatureBits()[Hexagon::ArchV60]) {
+      switch (NewOp) {
+      case Hexagon::J2_jumptpt:
+        NewOp = Hexagon::J2_jumpt;
+        break;
+      case Hexagon::J2_jumpfpt:
+        NewOp = Hexagon::J2_jumpf;
+        break;
+      case Hexagon::J2_jumprtpt:
+        NewOp = Hexagon::J2_jumprt;
+        break;
+      case Hexagon::J2_jumprfpt:
+        NewOp = Hexagon::J2_jumprf;
+        break;
+      }
+    }
     assert(NewOp >= 0 &&
            "Couldn't change predicate new instruction to its old form.");
   }
diff --git a/llvm/lib/Target/Hexagon/HexagonInstrInfo.h b/llvm/lib/Target/Hexagon/HexagonInstrInfo.h
index c1eb2165ce7..b268c7a2817 100644
--- a/llvm/lib/Target/Hexagon/HexagonInstrInfo.h
+++ b/llvm/lib/Target/Hexagon/HexagonInstrInfo.h
@@ -404,7 +404,7 @@ public:
                           const MachineBranchProbabilityInfo *MBPI) const;
   int getDotNewPredOp(const MachineInstr &MI,
                       const MachineBranchProbabilityInfo *MBPI) const;
-  int getDotOldOp(const int opc) const;
+  int getDotOldOp(const MachineInstr &MI) const;
   HexagonII::SubInstructionGroup getDuplexCandidateGroup(const MachineInstr &MI)
                                                          const;
   short getEquivalentHWInstr(const MachineInstr &MI) const;
diff --git a/llvm/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp b/llvm/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
index 1c904f2b7cd..3a789a5f7e0 100644
--- a/llvm/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
@@ -440,7 +440,7 @@ bool HexagonPacketizerList::promoteToDotNew(MachineInstr &MI,
 }
 
 bool HexagonPacketizerList::demoteToDotOld(MachineInstr &MI) {
-  int NewOpcode = HII->getDotOldOp(MI.getOpcode());
+  int NewOpcode = HII->getDotOldOp(MI);
   MI.setDesc(HII->get(NewOpcode));
   return true;
 }