AMDGPU/SI: Add implicit register operands in the correct order.

This commit fixes a bug in the class 'SIInstrInfo' where the implicit register
machine operands were added to a machine instruction in an incorrect order -
the implicit uses were added before the implicit defs.

I found this bug while working on moving the implicit register operand
verification code from the MIR parser to the machine verifier.

This commit also makes the method 'addImplicitDefUseOperands' in the machine
instruction class public so that it can be reused in the 'SIInstrInfo' class.

Reviewers: Matt Arsenault

Differential Revision: http://reviews.llvm.org/D11689

llvm-svn: 243799

4 files changed, 19 insertions, 24 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h
index be0b629a697..1a4d750a941 100644
--- a/llvm/include/llvm/CodeGen/MachineInstr.h
+++ b/llvm/include/llvm/CodeGen/MachineInstr.h
@@ -1180,6 +1180,8 @@ public:
     }
   }
 
+  /// Add all implicit def and use operands to this instruction.
+  void addImplicitDefUseOperands(MachineFunction &MF);
 
 private:
   /// If this instruction is embedded into a MachineFunction, return the
@@ -1187,9 +1189,6 @@ private:
   /// return null.
   MachineRegisterInfo *getRegInfo();
 
-  /// Add all implicit def and use operands to this instruction.
-  void addImplicitDefUseOperands(MachineFunction &MF);
-
   /// Unlink all of the register operands in this instruction from their
   /// respective use lists.  This requires that the operands already be on their
   /// use lists.
diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 9b391530a2f..aff4a57e1fa 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -2305,7 +2305,7 @@ void SIInstrInfo::moveToVALU(MachineInstr &TopInst) const {
       Inst->addOperand(MachineOperand::CreateImm(0));
     }
 
-    addDescImplicitUseDef(NewDesc, Inst);
+    Inst->addImplicitDefUseOperands(*Inst->getParent()->getParent());
 
     if (Opcode == AMDGPU::S_BFE_I32 || Opcode == AMDGPU::S_BFE_U32) {
       const MachineOperand &OffsetWidthOp = Inst->getOperand(2);
@@ -2593,24 +2593,6 @@ void SIInstrInfo::splitScalar64BitBFE(SmallVectorImpl<MachineInstr *> &Worklist,
   MRI.replaceRegWith(Dest.getReg(), ResultReg);
 }
 
-void SIInstrInfo::addDescImplicitUseDef(const MCInstrDesc &NewDesc,
-                                        MachineInstr *Inst) const {
-  // Add the implict and explicit register definitions.
-  if (NewDesc.ImplicitUses) {
-    for (unsigned i = 0; NewDesc.ImplicitUses[i]; ++i) {
-      unsigned Reg = NewDesc.ImplicitUses[i];
-      Inst->addOperand(MachineOperand::CreateReg(Reg, false, true));
-    }
-  }
-
-  if (NewDesc.ImplicitDefs) {
-    for (unsigned i = 0; NewDesc.ImplicitDefs[i]; ++i) {
-      unsigned Reg = NewDesc.ImplicitDefs[i];
-      Inst->addOperand(MachineOperand::CreateReg(Reg, true, true));
-    }
-  }
-}
-
 unsigned SIInstrInfo::findUsedSGPR(const MachineInstr *MI,
                                    int OpIndices[3]) const {
   const MCInstrDesc &Desc = get(MI->getOpcode());
diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.h b/llvm/lib/Target/AMDGPU/SIInstrInfo.h
index 4f3b0b3fd71..da60ad372db 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.h
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.h
@@ -58,8 +58,6 @@ private:
   void splitScalar64BitBFE(SmallVectorImpl<MachineInstr *> &Worklist,
                            MachineInstr *Inst) const;
 
-  void addDescImplicitUseDef(const MCInstrDesc &Desc, MachineInstr *MI) const;
-
   bool checkInstOffsetsDoNotOverlap(MachineInstr *MIa,
                                     MachineInstr *MIb) const;
 
diff --git a/llvm/test/CodeGen/AMDGPU/si-instr-info-correct-implicit-operands.ll b/llvm/test/CodeGen/AMDGPU/si-instr-info-correct-implicit-operands.ll
new file mode 100644
index 00000000000..dfd5f6b435f
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/si-instr-info-correct-implicit-operands.ll
@@ -0,0 +1,16 @@
+; RUN: llc -o /dev/null %s -march=amdgcn -mcpu=verde -verify-machineinstrs -stop-after expand-isel-pseudos 2>&1 | FileCheck %s
+; This test verifies that the instruction selection will add the implicit
+; register operands in the correct order when modifying the opcode of an
+; instruction to V_ADD_I32_e32.
+
+; CHECK: %19 = V_ADD_I32_e32 killed %13, killed %12, implicit-def %vcc, implicit %exec
+
+define void @test(i32 addrspace(1)* %out, i32 addrspace(1)* %in) {
+entry:
+  %b_ptr = getelementptr i32, i32 addrspace(1)* %in, i32 1
+  %a = load i32, i32 addrspace(1)* %in
+  %b = load i32, i32 addrspace(1)* %b_ptr
+  %result = add i32 %a, %b
+  store i32 %result, i32 addrspace(1)* %out
+  ret void
+}