Remove combine logic

Author: mtsokol

llvm/include/llvm/Target/GlobalISel/Combine.td

@@ -430,12 +430,6 @@ def binop_right_undef_to_undef: GICombineRule<
          [{ return Helper.matchOperandIsUndef(*${root}, 2); }]),
   (apply [{ Helper.replaceInstWithUndef(*${root}); }])>;
 
-def binop_right_poison_to_poison
-    : GICombineRule<(defs root:$root),
-                    (match(wip_match_opcode G_SHL, G_ASHR, G_LSHR):$root,
-                        [{ return Helper.matchOperandIsPoison(*${root}, 2); }]),
-                    (apply [{ Helper.replaceInstWithPoison(*${root}); }])>;
-
 def unary_undef_to_zero: GICombineRule<
   (defs root:$root),
   (match (wip_match_opcode G_ABS):$root,
@@ -453,17 +447,6 @@ def unary_undef_to_undef : GICombineRule<
   (match (unary_undef_to_undef_frags $dst)),
   (apply [{ Helper.replaceInstWithUndef(*${dst}.getParent()); }])>;
 
-def unary_poison_to_poison_frags
-    : GICombinePatFrag<(outs root:$dst), (ins),
-                       !foreach(op,
-                                [G_TRUNC, G_BITCAST, G_ANYEXT, G_PTRTOINT,
-                                 G_INTTOPTR, G_FPTOSI, G_FPTOUI],
-                                (pattern(op $dst, $x), (G_POISON $x)))>;
-def unary_poison_to_poison
-    : GICombineRule<
-          (defs root:$dst), (match(unary_poison_to_poison_frags $dst)),
-          (apply [{ Helper.replaceInstWithPoison(*${dst}.getParent()); }])>;
-
 // Instructions where if any source operand is undef, the instruction can be
 // replaced with undef.
 def propagate_undef_any_op: GICombineRule<
@@ -472,15 +455,6 @@ def propagate_undef_any_op: GICombineRule<
          [{ return Helper.matchAnyExplicitUseIsUndef(*${root}); }]),
   (apply [{ Helper.replaceInstWithUndef(*${root}); }])>;
 
-// Instructions where if any source operand is poison, the instruction can be
-// replaced with poison.
-def propagate_poison_any_op
-    : GICombineRule<
-          (defs root:$root),
-          (match(wip_match_opcode G_ADD, G_SUB, G_XOR):$root,
-              [{ return Helper.matchAnyExplicitUseIsPoison(*${root}); }]),
-          (apply [{ Helper.replaceInstWithPoison(*${root}); }])>;
-
 // Instructions where if all source operands are undef, the instruction can be
 // replaced with undef.
 def propagate_undef_all_ops: GICombineRule<
@@ -489,15 +463,6 @@ def propagate_undef_all_ops: GICombineRule<
           [{ return Helper.matchAllExplicitUsesAreUndef(*${root}); }]),
   (apply [{ Helper.replaceInstWithUndef(*${root}); }])>;
 
-// Instructions where if all source operands are poison, the instruction can be
-// replaced with poison.
-def propagate_poison_all_ops
-    : GICombineRule<
-          (defs root:$root),
-          (match(wip_match_opcode G_SHUFFLE_VECTOR, G_BUILD_VECTOR):$root,
-              [{ return Helper.matchAllExplicitUsesArePoison(*${root}); }]),
-          (apply [{ Helper.replaceInstWithPoison(*${root}); }])>;
-
 // Replace a G_SHUFFLE_VECTOR with an undef mask with a G_IMPLICIT_DEF.
 def propagate_undef_shuffle_mask: GICombineRule<
   (defs root:$root),
@@ -689,13 +654,6 @@ def erase_undef_store : GICombineRule<
   (apply [{ Helper.eraseInst(*${root}); }])
 >;
 
-// Erase stores of poison values.
-def erase_poison_store
-    : GICombineRule<(defs root:$root),
-                    (match(wip_match_opcode G_STORE):$root,
-                        [{ return Helper.matchPoisonStore(*${root}); }]),
-                    (apply [{ Helper.eraseInst(*${root}); }])>;
-
 def simplify_add_to_sub_matchinfo: GIDefMatchData<"std::tuple<Register, Register>">;
 def simplify_add_to_sub: GICombineRule <
   (defs root:$root, simplify_add_to_sub_matchinfo:$info),
@@ -2023,11 +1981,6 @@ def undef_combines : GICombineGroup<[undef_to_fp_zero, undef_to_int_zero,
                                      erase_undef_store,
                                      insert_extract_vec_elt_out_of_bounds]>;
 
-def poison_combines
-    : GICombineGroup<[binop_right_poison_to_poison, unary_poison_to_poison,
-                      propagate_poison_any_op, propagate_poison_all_ops,
-                      erase_poison_store]>;
-
 def identity_combines : GICombineGroup<[select_same_val, right_identity_zero,
                                         binop_same_val, binop_left_to_zero,
                                         binop_right_to_zero, p2i_to_i2p,
@@ -2083,7 +2036,7 @@ def all_combines : GICombineGroup<[integer_reassoc_combines, trivial_combines,
     vector_ops_combines, freeze_combines, cast_combines,
     insert_vec_elt_combines, extract_vec_elt_combines, combines_for_extload,
     combine_extracted_vector_load,
-    undef_combines, poison_combines, identity_combines, phi_combines,
+    undef_combines, identity_combines, phi_combines,
     simplify_add_to_sub, hoist_logic_op_with_same_opcode_hands, shifts_too_big,
     reassocs, ptr_add_immed_chain, cmp_combines,
     shl_ashr_to_sext_inreg, neg_and_one_to_sext_inreg, sext_inreg_of_load,

llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp

@@ -330,7 +330,6 @@ bool CombinerHelper::matchCombineConcatVectors(
       for (const MachineOperand &BuildVecMO : Def->uses())
         Ops.push_back(BuildVecMO.getReg());
       break;
-    case TargetOpcode::G_POISON:
     case TargetOpcode::G_IMPLICIT_DEF: {
       LLT OpType = MRI.getType(Reg);
       // Keep one undef value for all the undef operands.
@@ -3128,7 +3127,6 @@ bool CombinerHelper::matchCombineInsertVecElts(
   // If we didn't end in a G_IMPLICIT_DEF and the source is not fully
   // overwritten, bail out.
   return TmpInst->getOpcode() == TargetOpcode::G_IMPLICIT_DEF ||
-         TmpInst->getOpcode() == TargetOpcode::G_POISON ||
          all_of(MatchInfo, [](Register Reg) { return !!Reg; });
 }
 
@@ -3499,13 +3497,12 @@ bool CombinerHelper::matchUseVectorTruncate(MachineInstr &MI,
   if (I < 2)
     return false;
 
-  // Check the remaining source elements are only G_IMPLICIT_DEF or G_POISON
+  // Check the remaining source elements are only G_IMPLICIT_DEF
   for (; I < NumOperands; ++I) {
     auto SrcMI = MRI.getVRegDef(BuildMI->getSourceReg(I));
     auto SrcMIOpc = SrcMI->getOpcode();
 
-    if (SrcMIOpc != TargetOpcode::G_IMPLICIT_DEF &&
-        SrcMIOpc != TargetOpcode::G_POISON)
+    if (SrcMIOpc != TargetOpcode::G_IMPLICIT_DEF)
       return false;
   }
 
@@ -7966,12 +7963,6 @@ bool CombinerHelper::matchShuffleDisjointMask(MachineInstr &MI,
   if (getOpcodeDef(TargetOpcode::G_IMPLICIT_DEF, Shuffle.getSrc2Reg(), MRI))
     return false;
 
-  if (getOpcodeDef(TargetOpcode::G_POISON, Shuffle.getSrc1Reg(), MRI))
-    return false;
-
-  if (getOpcodeDef(TargetOpcode::G_POISON, Shuffle.getSrc2Reg(), MRI))
-    return false;
-
   const LLT DstTy = MRI.getType(Shuffle.getReg(0));
   const LLT Src1Ty = MRI.getType(Shuffle.getSrc1Reg());
   if (!isLegalOrBeforeLegalizer(