Handle register mask operands in setPhysRegsDeadExcept().

Calls that use register mask operands don't have implicit defs for
returned values.  The register mask operand handles the call clobber,
but it always behaves like a set of dead defs.

Add live implicit defs for any implicitly defined physregs that are
actually used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149715 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/MachineInstr.h b/include/llvm/CodeGen/MachineInstr.h
index 22a7ef205db0ab9e285b09d703559ac873219d37..4ccc37299c34da8f8bd6d518047f7af0eaba7089 100644 (file)
--- a/include/llvm/CodeGen/MachineInstr.h
+++ b/include/llvm/CodeGen/MachineInstr.h
@@ -792,6 +792,9 @@ public:
 
   /// setPhysRegsDeadExcept - Mark every physreg used by this instruction as
   /// dead except those in the UsedRegs list.
+  ///
+  /// On instructions with register mask operands, also add implicit-def
+  /// operands for all registers in UsedRegs.
   void setPhysRegsDeadExcept(ArrayRef<unsigned> UsedRegs,
                              const TargetRegisterInfo &TRI);
 

diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 6ce01a46ed18aa77bcc58b6407ddbec27bfe7941..de2082a779b4df13e8c87bfa0eefa7325766ab18 100644 (file)
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1795,8 +1795,13 @@ void MachineInstr::addRegisterDefined(unsigned IncomingReg,
 
 void MachineInstr::setPhysRegsDeadExcept(ArrayRef<unsigned> UsedRegs,
                                          const TargetRegisterInfo &TRI) {
+  bool HasRegMask = false;
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
     MachineOperand &MO = getOperand(i);
+    if (MO.isRegMask()) {
+      HasRegMask = true;
+      continue;
+    }
     if (!MO.isReg() || !MO.isDef()) continue;
     unsigned Reg = MO.getReg();
     if (!TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
@@ -1810,6 +1815,13 @@ void MachineInstr::setPhysRegsDeadExcept(ArrayRef<unsigned> UsedRegs,
     // If there are no uses, including partial uses, the def is dead.
     if (Dead) MO.setIsDead();
   }
+
+  // This is a call with a register mask operand.
+  // Mask clobbers are always dead, so add defs for the non-dead defines.
+  if (HasRegMask)
+    for (ArrayRef<unsigned>::iterator I = UsedRegs.begin(), E = UsedRegs.end();
+         I != E; ++I)
+      addRegisterDefined(*I, &TRI);
 }
 
 unsigned