setOperand should not zap the operand list or add implicit operands to an

instruction.  Doing so breaks the FP stackifier, the alpha branch selector
the sparc fpmover.

This fixes PR1012 and CodeGen/X86/fp-stack-compare.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31876 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 1 insertions, 40 deletions

diff --git a/include/llvm/CodeGen/MachineInstr.h b/include/llvm/CodeGen/MachineInstr.h
index 907985877f..7ad33f596f 100644
--- a/include/llvm/CodeGen/MachineInstr.h
+++ b/include/llvm/CodeGen/MachineInstr.h
@@ -490,7 +490,7 @@ public:
 
   /// setOpcode - Replace the opcode of the current instruction with a new one.
   ///
-  void setOpcode(unsigned Op);
+  void setOpcode(unsigned Op) { Opcode = Op; }
 
   /// RemoveOperand - Erase an operand  from an instruction, leaving it with one
   /// fewer operand than it started with.
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 41e2cdfe83..16e235a679 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -180,45 +180,6 @@ bool MachineOperand::isIdenticalTo(const MachineOperand &Other) const {
   }
 }
 
-/// setOpcode - Replace the opcode of the current instruction with a new one.
-///
-void MachineInstr::setOpcode(unsigned Op) {
-  Operands.erase(Operands.begin(), Operands.begin()+NumImplicitOps);
-  NumImplicitOps = 0;
-  Opcode = Op;
-  if (!getParent())
-    return;
-  const TargetInstrDescriptor &TID = getParent()->getParent()->
-    getTarget().getInstrInfo()->get(Op);
-  if (TID.ImplicitDefs)
-    for (const unsigned *ImpDefs = TID.ImplicitDefs; *ImpDefs; ++ImpDefs) {
-      MachineOperand Op;
-      Op.opType = MachineOperand::MO_Register;
-      Op.IsDef = true;
-      Op.IsImp = true;
-      Op.IsKill = false;
-      Op.IsDead = false;
-      Op.contents.RegNo = *ImpDefs;
-      Op.offset = 0;
-      Operands.insert(Operands.begin()+NumImplicitOps, Op);
-      NumImplicitOps++;
-    }
-  if (TID.ImplicitUses)
-    for (const unsigned *ImpUses = TID.ImplicitUses; *ImpUses; ++ImpUses) {
-      MachineOperand Op;
-      Op.opType = MachineOperand::MO_Register;
-      Op.IsDef = false;
-      Op.IsImp = true;
-      Op.IsKill = false;
-      Op.IsDead = false;
-      Op.contents.RegNo = *ImpUses;
-      Op.offset = 0;
-      Operands.insert(Operands.begin()+NumImplicitOps, Op);
-      NumImplicitOps++;
-    }
-}
-
-
 void MachineInstr::dump() const {
   std::cerr << "  " << *this;
 }