From 9d3e0705240333d07c028cf0e682d1e393e63020 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20Sch=C3=BCrmann?= Date: Mon, 11 Nov 2019 11:41:31 +0100 Subject: [PATCH] aco: value number instructions using the execution mask MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch tries to give instructions with the same execution mask also the same pass_flags and enables VN for SALU instructions using exec as Operand. This patch also adds back VN for VOPC instructions and removes VN for phis. v2 (by Timur Kristóf): - Fix some regressions. v3 (by Daniel Schürmann): - Fix additional issues Reviewed-By: Timur Kristóf Reviewed-by: Rhys Perry --- src/amd/compiler/aco_opt_value_numbering.cpp | 79 +++++++++++++------- 1 file changed, 51 insertions(+), 28 deletions(-) diff --git a/src/amd/compiler/aco_opt_value_numbering.cpp b/src/amd/compiler/aco_opt_value_numbering.cpp index fe094ebb219..803249637d5 100644 --- a/src/amd/compiler/aco_opt_value_numbering.cpp +++ b/src/amd/compiler/aco_opt_value_numbering.cpp @@ -81,17 +81,6 @@ struct InstrPred { return false; if (a->operands.size() != b->operands.size() || a->definitions.size() != b->definitions.size()) return false; /* possible with pseudo-instructions */ - /* We can't value number v_readlane_b32 across control flow or discards - * because of the possibility of live-range splits. - * We can't value number permutes for the same reason as - * v_readlane_b32 and because discards affect the result */ - if (a->opcode == aco_opcode::v_readfirstlane_b32 || a->opcode == aco_opcode::v_readlane_b32 || - a->opcode == aco_opcode::ds_bpermute_b32 || a->opcode == aco_opcode::ds_permute_b32 || - a->opcode == aco_opcode::ds_swizzle_b32 || a->format == Format::PSEUDO_REDUCTION || - a->opcode == aco_opcode::p_phi || a->opcode == aco_opcode::p_linear_phi) { - if (a->pass_flags != b->pass_flags) - return false; - } for (unsigned i = 0; i < a->operands.size(); i++) { if (a->operands[i].isConstant()) { if (!b->operands[i].isConstant()) @@ -108,11 +97,11 @@ struct InstrPred { else if (a->operands[i].isUndefined() ^ b->operands[i].isUndefined()) return false; if (a->operands[i].isFixed()) { - if (a->operands[i].physReg() == exec) - return false; if (!b->operands[i].isFixed()) return false; - if (!(a->operands[i].physReg() == b->operands[i].physReg())) + if (a->operands[i].physReg() != b->operands[i].physReg()) + return false; + if (a->operands[i].physReg() == exec && a->pass_flags != b->pass_flags) return false; } } @@ -126,10 +115,19 @@ struct InstrPred { if (a->definitions[i].isFixed()) { if (!b->definitions[i].isFixed()) return false; - if (!(a->definitions[i].physReg() == b->definitions[i].physReg())) + if (a->definitions[i].physReg() != b->definitions[i].physReg()) + return false; + if (a->definitions[i].physReg() == exec) return false; } } + + if (a->opcode == aco_opcode::v_readfirstlane_b32) + return a->pass_flags == b->pass_flags; + + /* The results of VOPC depend on the exec mask if used for subgroup operations. */ + if ((uint32_t) a->format & (uint32_t) Format::VOPC && a->pass_flags != b->pass_flags) + return false; if (a->format == Format::PSEUDO_BRANCH) return false; if (a->isVOP3()) { @@ -157,11 +155,6 @@ struct InstrPred { aDPP->neg[1] == bDPP->neg[1]; } switch (a->format) { - case Format::VOPC: { - /* Since the results depend on the exec mask, these shouldn't - * be value numbered (this is especially useful for subgroupBallot()). */ - return false; - } case Format::SOPK: { SOPK_instruction* aK = static_cast(a); SOPK_instruction* bK = static_cast(b); @@ -185,7 +178,9 @@ struct InstrPred { case Format::PSEUDO_REDUCTION: { Pseudo_reduction_instruction *aR = static_cast(a); Pseudo_reduction_instruction *bR = static_cast(b); - return aR->reduce_op == bR->reduce_op && aR->cluster_size == bR->cluster_size; + return aR->pass_flags == bR->pass_flags && + aR->reduce_op == bR->reduce_op && + aR->cluster_size == bR->cluster_size; } case Format::MTBUF: { /* this is fine since they are only used for vertex input fetches */ @@ -210,14 +205,16 @@ struct InstrPred { case Format::SCRATCH: return false; case Format::DS: { - /* we already handle potential issue with permute/swizzle above */ - DS_instruction* aD = static_cast(a); - DS_instruction* bD = static_cast(b); if (a->opcode != aco_opcode::ds_bpermute_b32 && a->opcode != aco_opcode::ds_permute_b32 && a->opcode != aco_opcode::ds_swizzle_b32) return false; - return aD->gds == bD->gds && aD->offset0 == bD->offset0 && aD->offset1 == bD->offset1; + DS_instruction* aD = static_cast(a); + DS_instruction* bD = static_cast(b); + return aD->pass_flags == bD->pass_flags && + aD->gds == bD->gds && + aD->offset0 == bD->offset0 && + aD->offset1 == bD->offset1; } case Format::MIMG: { MIMG_instruction* aM = static_cast(a); @@ -248,7 +245,13 @@ struct vn_ctx { Program* program; expr_set expr_values; std::map renames; - uint32_t exec_id = 0; + + /* The exec id should be the same on the same level of control flow depth. + * Together with the check for dominator relations, it is safe to assume + * that the same exec_id also means the same execution mask. + * Discards increment the exec_id, so that it won't return to the previous value. + */ + uint32_t exec_id = 1; vn_ctx(Program* program) : program(program) {} }; @@ -276,7 +279,7 @@ void process_block(vn_ctx& ctx, Block& block) op.setTemp(it->second); } - if (instr->definitions.empty()) { + if (instr->definitions.empty() || instr->opcode == aco_opcode::p_phi || instr->opcode == aco_opcode::p_linear_phi) { new_instructions.emplace_back(std::move(instr)); continue; } @@ -339,14 +342,34 @@ void rename_phi_operands(Block& block, std::map& renames) void value_numbering(Program* program) { vn_ctx ctx(program); + std::vector loop_headers; for (Block& block : program->blocks) { + assert(ctx.exec_id > 0); + /* decrement exec_id when leaving nested control flow */ + if (block.kind & block_kind_loop_header) + loop_headers.push_back(block.index); + if (block.kind & block_kind_merge) { + ctx.exec_id--; + } else if (block.kind & block_kind_loop_exit) { + ctx.exec_id -= program->blocks[loop_headers.back()].logical_preds.size(); + ctx.exec_id -= block.logical_preds.size(); + loop_headers.pop_back(); + } + if (block.logical_idom != -1) process_block(ctx, block); else rename_phi_operands(block, ctx.renames); - ctx.exec_id++; + /* increment exec_id when entering nested control flow */ + if (block.kind & block_kind_branch || + block.kind & block_kind_loop_preheader || + block.kind & block_kind_break || + block.kind & block_kind_continue) + ctx.exec_id++; + else if (block.kind & block_kind_continue_or_break) + ctx.exec_id += 2; } /* rename loop header phi operands */ -- 2.30.2