[PATCH] D24266: AMDGPU: Support commuting a FrameIndex operand

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: tstellarAMD.
arsenm added subscribers: llvm-commits, AMDGPU.
Herald added subscribers: nhaehnle, wdng, arsenm.

https://reviews.llvm.org/D24266

Files:
  include/llvm/CodeGen/MachineOperand.h
  lib/CodeGen/MachineInstr.cpp
  lib/Target/AMDGPU/SIInstrInfo.cpp
  test/CodeGen/AMDGPU/commute-compares.ll

Index: test/CodeGen/AMDGPU/commute-compares.ll
===================================================================
--- test/CodeGen/AMDGPU/commute-compares.ll
+++ test/CodeGen/AMDGPU/commute-compares.ll
@@ -693,5 +693,20 @@
   ret void
 }
 
+; Without commuting the frame index in the pre-regalloc run of
+; SIShrinkInstructions, this was using the VOP3 compare.
+
+; GCN-LABEL: {{^}}commute_frameindex:
+; GCN: v_cmp_eq_i32_e32 vcc, 0, v{{[0-9]+}}
+define void @commute_frameindex(i32 addrspace(1)* nocapture %out) #0 {
+entry:
+  %stack0 = alloca i32
+  %ptr0 = load volatile i32*, i32* addrspace(1)* undef
+  %eq = icmp eq i32* %ptr0, %stack0
+  %ext = zext i1 %eq to i32
+  store volatile i32 %ext, i32 addrspace(1)* %out
+  ret void
+}
+
 attributes #0 = { nounwind readnone }
 attributes #1 = { nounwind }
Index: lib/Target/AMDGPU/SIInstrInfo.cpp
===================================================================
--- lib/Target/AMDGPU/SIInstrInfo.cpp
+++ lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -930,16 +930,23 @@
 static MachineInstr *swapRegAndNonRegOperand(MachineInstr &MI,
                                              MachineOperand &RegOp,
                                              MachineOperand &ImmOp) {
-  // TODO: Handle other immediate like types.
-  if (!ImmOp.isImm())
+  unsigned Reg = RegOp.getReg();
+  unsigned SubReg = RegOp.getSubReg();
+  bool IsKill = RegOp.isKill();
+  bool IsDead = RegOp.isDead();
+  bool IsUndef = RegOp.isUndef();
+  bool IsDebug = RegOp.isDebug();
+
+  if (ImmOp.isImm())
+    RegOp.ChangeToImmediate(ImmOp.getImm());
+  else if (ImmOp.isFI())
+    RegOp.ChangeToFrameIndex(ImmOp.getIndex());
+  else
     return nullptr;
 
-  int64_t ImmVal = ImmOp.getImm();
-  ImmOp.ChangeToRegister(RegOp.getReg(), false, false,
-                         RegOp.isKill(), RegOp.isDead(), RegOp.isUndef(),
-                         RegOp.isDebug());
-  ImmOp.setSubReg(RegOp.getSubReg());
-  RegOp.ChangeToImmediate(ImmVal);
+  ImmOp.ChangeToRegister(Reg, false, false, IsKill, IsDead, IsUndef, IsDebug);
+  ImmOp.setSubReg(SubReg);
+
   return &MI;
 }
 
Index: lib/CodeGen/MachineInstr.cpp
===================================================================
--- lib/CodeGen/MachineInstr.cpp
+++ lib/CodeGen/MachineInstr.cpp
@@ -175,6 +175,16 @@
   Contents.Sym = Sym;
 }
 
+void MachineOperand::ChangeToFrameIndex(int Idx) {
+  assert((!isReg() || !isTied()) &&
+         "Cannot change a tied operand into a FrameIndex");
+
+  removeRegFromUses();
+
+  OpKind = MO_FrameIndex;
+  setIndex(Idx);
+}
+
 /// ChangeToRegister - Replace this operand with a new register operand of
 /// the specified value.  If an operand is known to be an register already,
 /// the setReg method should be used.
Index: include/llvm/CodeGen/MachineOperand.h
===================================================================
--- include/llvm/CodeGen/MachineOperand.h
+++ include/llvm/CodeGen/MachineOperand.h
@@ -593,6 +593,9 @@
   /// ChangeToMCSymbol - Replace this operand with a new MC symbol operand.
   void ChangeToMCSymbol(MCSymbol *Sym);
 
+  /// Replace this operand with a frame index.
+  void ChangeToFrameIndex(int Idx);
+
   /// ChangeToRegister - Replace this operand with a new register operand of
   /// the specified value.  If an operand is known to be an register already,
   /// the setReg method should be used.


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