Teach ADCE about OpImageTexelPointer

Currently OpImageTexelPointer operations are treat like a use of the pointer, but it does not look for the memory being referenced to make sure stores are not removed. This change teaches it so identify the memory being accessed, and treats it as if that memory is loaded. Contributes to #1445.
KhronosGroup · Apr 2, 2018 · 1fccc6c · 1fccc6c
1 parent fc9f621
commit 1fccc6c
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Showing 4 changed files with 56 additions and 7 deletions.
diff --git a/source/opt/aggressive_dead_code_elim_pass.cpp b/source/opt/aggressive_dead_code_elim_pass.cpp
@@ -433,6 +433,15 @@ bool AggressiveDCEPass::AggressiveDCE(ir::Function* func) {
     else if (liveInst->opcode() == SpvOpFunctionParameter) {
       ProcessLoad(liveInst->result_id());
     }
+    // We treat an OpImageTexelPointer as a load of the pointer, and
+    // that value is manipulated to get the result.
+    else if (liveInst->opcode() == SpvOpImageTexelPointer) {
+      uint32_t varId;
+      (void)GetPtr(liveInst, &varId);
+      if (varId != 0) {
+        ProcessLoad(varId);
+      }
+    }
     worklist_.pop();
   }
 

diff --git a/source/opt/instruction.cpp b/source/opt/instruction.cpp
@@ -158,8 +158,8 @@ bool Instruction::IsReadOnlyLoad() const {
 
 Instruction* Instruction::GetBaseAddress() const {
   assert((IsLoad() || opcode() == SpvOpStore || opcode() == SpvOpAccessChain ||
-          opcode() == SpvOpInBoundsAccessChain ||
-          opcode() == SpvOpCopyObject) &&
+          opcode() == SpvOpInBoundsAccessChain || opcode() == SpvOpCopyObject ||
+          opcode() == SpvOpImageTexelPointer) &&
          "GetBaseAddress should only be called on instructions that take a "
          "pointer or image.");
   uint32_t base = GetSingleWordInOperand(kLoadBaseIndex);

diff --git a/source/opt/mem_pass.cpp b/source/opt/mem_pass.cpp
@@ -28,9 +28,7 @@ namespace opt {
 namespace {
 
 const uint32_t kCopyObjectOperandInIdx = 0;
-const uint32_t kLoadPtrIdInIdx = 0;
 const uint32_t kLoopMergeMergeBlockIdInIdx = 0;
-const uint32_t kStorePtrIdInIdx = 0;
 const uint32_t kStoreValIdInIdx = 1;
 const uint32_t kTypePointerStorageClassInIdx = 0;
 const uint32_t kTypePointerTypeIdInIdx = 1;
@@ -120,9 +118,10 @@ ir::Instruction* MemPass::GetPtr(uint32_t ptrId, uint32_t* varId) {
 
 ir::Instruction* MemPass::GetPtr(ir::Instruction* ip, uint32_t* varId) {
   const SpvOp op = ip->opcode();
-  assert(op == SpvOpStore || op == SpvOpLoad);
-  const uint32_t ptrId = ip->GetSingleWordInOperand(
-      op == SpvOpStore ? kStorePtrIdInIdx : kLoadPtrIdInIdx);
+  assert(op == SpvOpStore || op == SpvOpLoad || op == SpvOpImageTexelPointer);
+
+  // All of these opcode place the pointer in position 0.
+  const uint32_t ptrId = ip->GetSingleWordInOperand(0);
   return GetPtr(ptrId, varId);
 }
 

diff --git a/test/opt/aggressive_dead_code_elim_test.cpp b/test/opt/aggressive_dead_code_elim_test.cpp
@@ -5369,6 +5369,47 @@ OpFunctionEnd
   SinglePassRunAndCheck<opt::AggressiveDCEPass>(text, text, true, true);
 }
 
+TEST_F(AggressiveDCETest, AtomicAdd) {
+  const std::string text = R"(OpCapability SampledBuffer
+OpCapability StorageImageExtendedFormats
+OpCapability ImageBuffer
+OpCapability Shader
+%1 = OpExtInstImport "GLSL.std.450"
+OpMemoryModel Logical GLSL450
+OpEntryPoint GLCompute %2 "min" %gl_GlobalInvocationID
+OpExecutionMode %2 LocalSize 64 1 1
+OpSource HLSL 600
+OpDecorate %gl_GlobalInvocationID BuiltIn GlobalInvocationId
+OpDecorate %4 DescriptorSet 4
+OpDecorate %4 Binding 70
+%uint = OpTypeInt 32 0
+%6 = OpTypeImage %uint Buffer 0 0 0 2 R32ui
+%_ptr_UniformConstant_6 = OpTypePointer UniformConstant %6
+%_ptr_Private_6 = OpTypePointer Private %6
+%void = OpTypeVoid
+%10 = OpTypeFunction %void
+%uint_0 = OpConstant %uint 0
+%uint_1 = OpConstant %uint 1
+%v3uint = OpTypeVector %uint 3
+%_ptr_Input_v3uint = OpTypePointer Input %v3uint
+%_ptr_Image_uint = OpTypePointer Image %uint
+%4 = OpVariable %_ptr_UniformConstant_6 UniformConstant
+%16 = OpVariable %_ptr_Private_6 Private
+%gl_GlobalInvocationID = OpVariable %_ptr_Input_v3uint Input
+%2 = OpFunction %void None %10
+%17 = OpLabel
+%18 = OpLoad %6 %4
+OpStore %16 %18
+%19 = OpImageTexelPointer %_ptr_Image_uint %16 %uint_0 %uint_0
+%20 = OpAtomicIAdd %uint %19 %uint_1 %uint_0 %uint_1
+OpReturn
+OpFunctionEnd
+)";
+
+  SetAssembleOptions(SPV_TEXT_TO_BINARY_OPTION_PRESERVE_NUMERIC_IDS);
+  SinglePassRunAndCheck<opt::AggressiveDCEPass>(text, text, true, true);
+}
+
 // TODO(greg-lunarg): Add tests to verify handling of these cases:
 //
 //    Check that logical addressing required