From 14712ad1536bc396f80b46561e05302a7715a8c9 Mon Sep 17 00:00:00 2001
From: "Alastair F. Donaldson" <alastair.donaldson@imperial.ac.uk>
Date: Fri, 28 May 2021 00:18:21 +0100
Subject: [PATCH] spirv-fuzz: Fix def-use update in PermutePhiOperands

The def-use manager was being incorrectly updated in
TransformationPermutePhiOperands, and this was causing future
transformations to go wrong during fuzzing. This change updates the
def-use manager in a correct manner, and adds a test exposing the
previous bug.

Fixes #4300.
---
 .../transformation_permute_phi_operands.cpp   |  3 +--
 ...ansformation_permute_phi_operands_test.cpp | 26 +++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/source/fuzz/transformation_permute_phi_operands.cpp b/source/fuzz/transformation_permute_phi_operands.cpp
index 605633124a..7ee7a82fa7 100644
--- a/source/fuzz/transformation_permute_phi_operands.cpp
+++ b/source/fuzz/transformation_permute_phi_operands.cpp
@@ -81,8 +81,7 @@ void TransformationPermutePhiOperands::Apply(
   inst->SetInOperands(std::move(permuted_operands));
 
   // Update the def-use manager.
-  ir_context->get_def_use_mgr()->ClearInst(inst);
-  ir_context->get_def_use_mgr()->AnalyzeInstDefUse(inst);
+  ir_context->UpdateDefUse(inst);
 }
 
 protobufs::Transformation TransformationPermutePhiOperands::ToMessage() const {
diff --git a/test/fuzz/transformation_permute_phi_operands_test.cpp b/test/fuzz/transformation_permute_phi_operands_test.cpp
index 3df399a55c..0774dcf3d0 100644
--- a/test/fuzz/transformation_permute_phi_operands_test.cpp
+++ b/test/fuzz/transformation_permute_phi_operands_test.cpp
@@ -60,6 +60,7 @@ TEST(TransformationPermutePhiOperandsTest, BasicTest) {
                OpBranch %17
          %17 = OpLabel
          %25 = OpPhi %6 %20 %16 %24 %21
+         %30 = OpIAdd %6 %25 %25
                OpStore %8 %25
                OpReturn
                OpFunctionEnd
@@ -121,6 +122,30 @@ TEST(TransformationPermutePhiOperandsTest, BasicTest) {
           return true;
         });
   }
+  bool found_use_in_store = false;
+  bool found_use_in_add_lhs = false;
+  bool found_use_in_add_rhs = false;
+  context->get_def_use_mgr()->ForEachUse(
+      25, [&found_use_in_store, &found_use_in_add_lhs, &found_use_in_add_rhs](
+              opt::Instruction* inst, uint32_t operand_index) {
+        if (inst->opcode() == SpvOpStore) {
+          ASSERT_FALSE(found_use_in_store);
+          found_use_in_store = true;
+        } else {
+          ASSERT_EQ(SpvOpIAdd, inst->opcode());
+          if (operand_index == 2) {
+            ASSERT_FALSE(found_use_in_add_lhs);
+            found_use_in_add_lhs = true;
+          } else {
+            ASSERT_EQ(3, operand_index);
+            ASSERT_FALSE(found_use_in_add_rhs);
+            found_use_in_add_rhs = true;
+          }
+        }
+      });
+  ASSERT_TRUE(found_use_in_store);
+  ASSERT_TRUE(found_use_in_add_lhs);
+  ASSERT_TRUE(found_use_in_add_rhs);
 
   std::string after_transformation = R"(
                OpCapability Shader
@@ -159,6 +184,7 @@ TEST(TransformationPermutePhiOperandsTest, BasicTest) {
                OpBranch %17
          %17 = OpLabel
          %25 = OpPhi %6 %24 %21 %20 %16
+         %30 = OpIAdd %6 %25 %25
                OpStore %8 %25
                OpReturn
                OpFunctionEnd