[PATCH] D69063: [AMDGPU] Do not combine dpp with physreg def

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG3d99310c15e4: [AMDGPU] Do not combine dpp with physreg def (authored by rampitec).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69063/new/

https://reviews.llvm.org/D69063

Files:
  llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
  llvm/test/CodeGen/AMDGPU/dpp_combine.mir


Index: llvm/test/CodeGen/AMDGPU/dpp_combine.mir
===================================================================
--- llvm/test/CodeGen/AMDGPU/dpp_combine.mir
+++ llvm/test/CodeGen/AMDGPU/dpp_combine.mir
@@ -563,6 +563,18 @@
     %3:vgpr_32 = V_CEIL_F32_e32 %2, implicit $exec
 ...
 
+# Do not combine a dpp mov which writes a physreg.
+# GCN-LABEL: name: phys_dpp_mov_dst
+# GCN: $vgpr0 = V_MOV_B32_dpp undef %0:vgpr_32, undef %1:vgpr_32, 1, 15, 15, 1, implicit $exec
+# GCN: %2:vgpr_32 = V_CEIL_F32_e32 $vgpr0, implicit $exec
+name: phys_dpp_mov_dst
+tracksRegLiveness: true
+body: |
+  bb.0:
+    $vgpr0 = V_MOV_B32_dpp undef %1:vgpr_32, undef %0:vgpr_32, 1, 15, 15, 1, implicit $exec
+    %2:vgpr_32 = V_CEIL_F32_e32 $vgpr0, implicit $exec
+...
+
 # GCN-LABEL: name: dpp_reg_sequence_both_combined
 # GCN: %0:vreg_64 = COPY $vgpr0_vgpr1
 # GCN: %1:vreg_64 = COPY $vgpr2_vgpr3
Index: llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
+++ llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
@@ -353,6 +353,10 @@
   auto *DstOpnd = TII->getNamedOperand(MovMI, AMDGPU::OpName::vdst);
   assert(DstOpnd && DstOpnd->isReg());
   auto DPPMovReg = DstOpnd->getReg();
+  if (DPPMovReg.isPhysical()) {
+    LLVM_DEBUG(dbgs() << "  failed: dpp move writes physreg\n");
+    return false;
+  }
   if (execMayBeModifiedBeforeAnyUse(*MRI, DPPMovReg, MovMI)) {
     LLVM_DEBUG(dbgs() << "  failed: EXEC mask should remain the same"
                          " for all uses\n");


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