From df96e243c633b939690a42d89904e04f50126e86 Mon Sep 17 00:00:00 2001
From: Lei Zhang <antiagainst@google.com>
Date: Sat, 22 Jul 2017 10:48:28 -0400
Subject: [PATCH] Revert "Opt: LocalBlockElim: Add HasOnlySupportedRefs"

This reverts commit 2d0f7fbc1151004c4cf111b947f1070a03dfe092.
---
 source/opt/aggressive_dead_code_elim_pass.cpp |  1 +
 source/opt/local_single_block_elim_pass.cpp   | 25 -------------------------
 source/opt/local_single_block_elim_pass.h     |  8 --------
 source/opt/local_ssa_elim_pass.h              |  3 ++-
 4 files changed, 3 insertions(+), 34 deletions(-)

diff --git a/source/opt/aggressive_dead_code_elim_pass.cpp b/source/opt/aggressive_dead_code_elim_pass.cpp
index 85e8041..8238206 100644
--- a/source/opt/aggressive_dead_code_elim_pass.cpp
+++ b/source/opt/aggressive_dead_code_elim_pass.cpp
@@ -231,6 +231,7 @@ bool AggressiveDCEPass::AggressiveDCE(ir::Function* func) {
 }
 
 void AggressiveDCEPass::Initialize(ir::Module* module) {
+
   module_ = module;
 
   // Initialize id-to-function map
diff --git a/source/opt/local_single_block_elim_pass.cpp b/source/opt/local_single_block_elim_pass.cpp
index c3c6613..39d7ba5 100644
--- a/source/opt/local_single_block_elim_pass.cpp
+++ b/source/opt/local_single_block_elim_pass.cpp
@@ -218,24 +218,6 @@ void LocalSingleBlockLoadStoreElimPass::DCEInst(ir::Instruction* inst) {
   }
 }
 
-bool LocalSingleBlockLoadStoreElimPass::HasOnlySupportedRefs(uint32_t ptrId) {
-  if (supported_ref_ptrs_.find(ptrId) != supported_ref_ptrs_.end())
-    return true;
-  analysis::UseList* uses = def_use_mgr_->GetUses(ptrId);
-  assert(uses != nullptr);
-  for (auto u : *uses) {
-    SpvOp op = u.inst->opcode();
-    if (IsNonPtrAccessChain(op)) {
-      if (!HasOnlySupportedRefs(u.inst->result_id()))
-        return false;
-    }
-    else if (op != SpvOpStore && op != SpvOpLoad && op != SpvOpName)
-      return false;
-  }
-  supported_ref_ptrs_.insert(ptrId);
-  return true;
-}
-
 bool LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElim(
     ir::Function* func) {
   // Perform local store/load and load/load elimination on each block
@@ -252,8 +234,6 @@ bool LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElim(
         ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
         if (!IsTargetVar(varId))
           continue;
-        if (!HasOnlySupportedRefs(varId))
-          continue;
         // Register the store
         if (ptrInst->opcode() == SpvOpVariable) {
           // if not pinned, look for WAW
@@ -278,8 +258,6 @@ bool LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElim(
         ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
         if (!IsTargetVar(varId))
           continue;
-        if (!HasOnlySupportedRefs(varId))
-          continue;
         // Look for previous store or load
         uint32_t replId = 0;
         if (ptrInst->opcode() == SpvOpVariable) {
@@ -342,9 +320,6 @@ void LocalSingleBlockLoadStoreElimPass::Initialize(ir::Module* module) {
   seen_target_vars_.clear();
   seen_non_target_vars_.clear();
 
-  // Clear collections
-  supported_ref_ptrs_.clear();
-
   // TODO(): Reuse def/use from previous passes
   def_use_mgr_.reset(new analysis::DefUseManager(consumer(), module_));
 
diff --git a/source/opt/local_single_block_elim_pass.h b/source/opt/local_single_block_elim_pass.h
index 2476f26..b5a14f4 100644
--- a/source/opt/local_single_block_elim_pass.h
+++ b/source/opt/local_single_block_elim_pass.h
@@ -85,10 +85,6 @@ class LocalSingleBlockLoadStoreElimPass : public Pass {
   // labels. 
   void DCEInst(ir::Instruction* inst);
 
-  // Return true if all uses of |varId| are only through supported reference
-  // operations ie. loads and store. Also cache in supported_ref_ptrs_;
-  bool HasOnlySupportedRefs(uint32_t varId);
-
   // On all entry point functions, within each basic block, eliminate
   // loads and stores to function variables where possible. For
   // loads, if previous load or store to same variable, replace
@@ -146,10 +142,6 @@ class LocalSingleBlockLoadStoreElimPass : public Pass {
   // from this set each time a new store of that variable is encountered.
   std::unordered_set<uint32_t> pinned_vars_;
 
-  // Variables that are only referenced by supported operations for this
-  // pass ie. loads and stores.
-  std::unordered_set<uint32_t> supported_ref_ptrs_;
-
   // Next unused ID
   uint32_t next_id_;
 };
diff --git a/source/opt/local_ssa_elim_pass.h b/source/opt/local_ssa_elim_pass.h
index 7459c76..7cce51a 100644
--- a/source/opt/local_ssa_elim_pass.h
+++ b/source/opt/local_ssa_elim_pass.h
@@ -184,7 +184,8 @@ class LocalMultiStoreElimPass : public Pass {
   // the runtime and effectiveness of this function.
   bool EliminateMultiStoreLocal(ir::Function* func);
 
-  // Return true if |op| is decorate.
+  // Return true if all uses of varId are only through supported reference
+  // operations ie. loads and store. Also cache in supported_ref_vars_;
   inline bool IsDecorate(uint32_t op) const {
     return (op == SpvOpDecorate || op == SpvOpDecorateId);
   }
-- 
2.7.4