[AMDGPU] Stop looking for implicit M0 uses on MOV instructions

Before D114230, indirect moves used regular MOV opcodes and were
identified by having an implicit use of M0. Since D114230 they use
dedicated opcodes instead, so remove some old code that checks for
implicit uses of M0. NFCI.

Differential Revision: https://reviews.llvm.org/D138308

diff --git a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
index f571bcd..979f335 100644 (file)
--- a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -449,24 +449,10 @@ bool SIFoldOperands::tryAddToFoldList(SmallVectorImpl<FoldCandidate> &FoldList,
   return true;
 }
 
-// If the use operand doesn't care about the value, this may be an operand only
-// used for register indexing, in which case it is unsafe to fold.
 bool SIFoldOperands::isUseSafeToFold(const MachineInstr &MI,
                                      const MachineOperand &UseMO) const {
-  if (UseMO.isUndef() || TII->isSDWA(MI))
-    return false;
-
-  switch (MI.getOpcode()) {
-  case AMDGPU::V_MOV_B32_e32:
-  case AMDGPU::V_MOV_B32_e64:
-  case AMDGPU::V_MOV_B64_PSEUDO:
-  case AMDGPU::V_MOV_B64_e32:
-  case AMDGPU::V_MOV_B64_e64:
-    // Do not fold into an indirect mov.
-    return !MI.hasRegisterImplicitUseOperand(AMDGPU::M0);
-  }
-
-  return true;
+  // Operands of SDWA instructions must be registers.
+  return !TII->isSDWA(MI);
 }
 
 // Find a def of the UseReg, check if it is a reg_sequence and find initializers

diff --git a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
index c54d23e..0e01d93 100644 (file)
--- a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
+++ b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
@@ -637,9 +637,6 @@ MachineInstr *SIShrinkInstructions::matchSwap(MachineInstr &MovT) const {
   if (!TRI->isVGPR(*MRI, X))
     return nullptr;
 
-  if (MovT.hasRegisterImplicitUseOperand(AMDGPU::M0))
-    return nullptr;
-
   const unsigned SearchLimit = 16;
   unsigned Count = 0;
   bool KilledT = false;
@@ -654,8 +651,7 @@ MachineInstr *SIShrinkInstructions::matchSwap(MachineInstr &MovT) const {
          MovY->getOpcode() != AMDGPU::COPY) ||
         !MovY->getOperand(1).isReg()        ||
         MovY->getOperand(1).getReg() != T   ||
-        MovY->getOperand(1).getSubReg() != Tsub ||
-        MovY->hasRegisterImplicitUseOperand(AMDGPU::M0))
+        MovY->getOperand(1).getSubReg() != Tsub)
       continue;
 
     Register Y = MovY->getOperand(0).getReg();
@@ -688,9 +684,6 @@ MachineInstr *SIShrinkInstructions::matchSwap(MachineInstr &MovT) const {
         MovX = nullptr;
         break;
       }
-      // Implicit use of M0 is an indirect move.
-      if (I->hasRegisterImplicitUseOperand(AMDGPU::M0))
-        continue;
 
       if (Size > 1 && (I->getNumImplicitOperands() > (I->isCopy() ? 0U : 1U)))
         continue;

diff --git a/llvm/test/CodeGen/AMDGPU/v_swap_b32.mir b/llvm/test/CodeGen/AMDGPU/v_swap_b32.mir
index 2220633..83c2d06 100644 (file)
--- a/llvm/test/CodeGen/AMDGPU/v_swap_b32.mir
+++ b/llvm/test/CodeGen/AMDGPU/v_swap_b32.mir
@@ -848,7 +848,7 @@ body:             |
 ...
 
 # GCN-LABEL: name: indirect_mov_t
-# GCN:      $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec, implicit $m0
+# GCN:      $vgpr2 = V_MOV_B32_indirect_read killed $vgpr0, implicit $exec, implicit $m0
 # GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
 # GCN-NEXT: $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec
 # GCN-NEXT: S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
@@ -859,7 +859,7 @@ tracksRegLiveness: true
 body:             |
   bb.0:
     liveins: $vgpr0, $vgpr1, $sgpr30_sgpr31
-    $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec, implicit $m0
+    $vgpr2 = V_MOV_B32_indirect_read killed $vgpr0, implicit $exec, implicit $m0
     $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
     $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec
     S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
@@ -867,7 +867,7 @@ body:             |
 
 # GCN-LABEL: name: indirect_mov_x
 # GCN:      $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec
-# GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $m0
+# GCN-NEXT: $vgpr0 = V_MOV_B32_indirect_read killed $vgpr1, implicit $exec, implicit $m0
 # GCN-NEXT: $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec
 # GCN-NEXT: S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
 
@@ -878,7 +878,7 @@ body:             |
   bb.0:
     liveins: $vgpr0, $vgpr1, $sgpr30_sgpr31
     $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec
-    $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec, implicit $m0
+    $vgpr0 = V_MOV_B32_indirect_read killed $vgpr1, implicit $exec, implicit $m0
     $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec
     S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
 ...
@@ -886,7 +886,7 @@ body:             |
 # GCN-LABEL: name: indirect_mov_y
 # GCN:      $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec
 # GCN-NEXT: $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
-# GCN-NEXT: $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec, implicit $m0
+# GCN-NEXT: $vgpr1 = V_MOV_B32_indirect_read killed $vgpr2, implicit $exec, implicit $m0
 # GCN-NEXT: S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
 
 ---
@@ -897,7 +897,7 @@ body:             |
     liveins: $vgpr0, $vgpr1, $sgpr30_sgpr31
     $vgpr2 = V_MOV_B32_e32 killed $vgpr0, implicit $exec
     $vgpr0 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
-    $vgpr1 = V_MOV_B32_e32 killed $vgpr2, implicit $exec, implicit $m0
+    $vgpr1 = V_MOV_B32_indirect_read killed $vgpr2, implicit $exec, implicit $m0
     S_SETPC_B64_return $sgpr30_sgpr31, implicit $vgpr0, implicit $vgpr1
 ...