[clang] [llvm] [NFC] Remove unused-but-set global variables (PR #189315)

[John Paul Jepko via cfe-commits]

https://github.com/jpjepko created https://github.com/llvm/llvm-project/pull/189315

Remove four global variables that are set but never read to fix -Wunused-but-set-global warnings:

- `MFMAChainLength` in AMDGPUIGroupLP.cpp
- `Wide` in llvm-objdump.cpp
- `SaveTemps` in ClangSYCLLinker.cpp
- `DeprecatedDriverCommand` in ClangScanDeps.cpp

>From 0483093866c5ce740c9bc664cbae68fea45bc786 Mon Sep 17 00:00:00 2001
From: John Jepko <john.jepko at ericsson.com>
Date: Sun, 29 Mar 2026 04:30:37 +0200
Subject: [PATCH] [NFC] Remove unused-but-set global variables

Remove four global variables that are set but never read to fix
-Wunused-but-set-global warnings.
---
 clang/tools/clang-scan-deps/ClangScanDeps.cpp     | 3 +--
 clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp | 5 +----
 llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp         | 5 -----
 llvm/tools/llvm-objdump/llvm-objdump.cpp          | 3 +--
 4 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/clang/tools/clang-scan-deps/ClangScanDeps.cpp b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
index 8666222984ac0..b2d040eae4cb6 100644
--- a/clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -91,7 +91,6 @@ static std::string CompilationDB;
 static std::optional<std::string> ModuleNames;
 static std::vector<std::string> ModuleDepTargets;
 static std::string TranslationUnitFile;
-static bool DeprecatedDriverCommand;
 static ResourceDirRecipeKind ResourceDirRecipe;
 static bool Verbose;
 static bool AsyncScanModules;
@@ -216,7 +215,7 @@ static void ParseArgs(int argc, char **argv) {
   if (const llvm::opt::Arg *A = Args.getLastArg(OPT_tu_buffer_path_EQ))
     TranslationUnitFile = A->getValue();
 
-  DeprecatedDriverCommand = Args.hasArg(OPT_deprecated_driver_command);
+  Args.hasArg(OPT_deprecated_driver_command);
 
   if (const llvm::opt::Arg *A = Args.getLastArg(OPT_resource_dir_recipe_EQ)) {
     auto Kind =
diff --git a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
index 92068b655d65d..f2f7c07f62ae8 100644
--- a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
+++ b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
@@ -52,9 +52,6 @@ using namespace llvm::opt;
 using namespace llvm::object;
 using namespace clang;
 
-/// Save intermediary results.
-static bool SaveTemps = false;
-
 /// Print commands/steps with arguments without executing.
 static bool DryRun = false;
 
@@ -591,7 +588,7 @@ int main(int argc, char **argv) {
 
   Verbose = Args.hasArg(OPT_verbose);
   DryRun = Args.hasArg(OPT_dry_run);
-  SaveTemps = Args.hasArg(OPT_save_temps);
+  Args.hasArg(OPT_save_temps);
 
   if (!Args.hasArg(OPT_o))
     reportError(createStringError("Output file must be specified"));
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp b/llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp
index 07252252fa35f..d49ec90e4c212 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUIGroupLP.cpp
@@ -910,8 +910,6 @@ class MFMAExpInterleaveOpt final : public IGLPStrategy {
   static unsigned ExpRequirement;
   // The count of independent "chains" of MFMA instructions in the pipeline
   static unsigned MFMAChains;
-  // The length of each independent "chain" of MFMA instructions
-  static unsigned MFMAChainLength;
   // Whether or not the pipeline has V_CVT instructions
   static bool HasCvt;
   // Whether or not there are instructions between the TRANS instruction and
@@ -1340,7 +1338,6 @@ unsigned MFMAExpInterleaveOpt::AddPipeCount = 0;
 unsigned MFMAExpInterleaveOpt::MFMAEnablement = 0;
 unsigned MFMAExpInterleaveOpt::ExpRequirement = 0;
 unsigned MFMAExpInterleaveOpt::MFMAChains = 0;
-unsigned MFMAExpInterleaveOpt::MFMAChainLength = 0;
 bool MFMAExpInterleaveOpt::HasCvt = false;
 bool MFMAExpInterleaveOpt::HasChainBetweenCvt = false;
 std::optional<unsigned> MFMAExpInterleaveOpt::FirstPipeDSR = std::nullopt;
@@ -1478,8 +1475,6 @@ bool MFMAExpInterleaveOpt::analyzeDAG(const SIInstrInfo *TII) {
       FirstPipeDSR = Pred.getSUnit()->NodeNum;
   }
 
-  MFMAChainLength = MFMAPipeCount / MFMAChains;
-
   // The number of bit pack operations that depend on a single V_EXP
   unsigned PackSuccCount =
       llvm::count_if(PackSUs, [this, &TempExp](SUnit *VPack) {
diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index ec2ecb58d6385..8175b6463b24d 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -340,7 +340,6 @@ static bool PrettyPGOAnalysisMap;
 static bool DynamicSymbolTable;
 std::string objdump::TripleName;
 bool objdump::UnwindInfo;
-static bool Wide;
 std::string objdump::Prefix;
 uint32_t objdump::PrefixStrip;
 
@@ -3764,7 +3763,7 @@ static void parseObjdumpOptions(const llvm::opt::InputArgList &InputArgs) {
   DynamicSymbolTable = InputArgs.hasArg(OBJDUMP_dynamic_syms);
   TripleName = InputArgs.getLastArgValue(OBJDUMP_triple_EQ).str();
   UnwindInfo = InputArgs.hasArg(OBJDUMP_unwind_info);
-  Wide = InputArgs.hasArg(OBJDUMP_wide);
+  InputArgs.hasArg(OBJDUMP_wide);
   Prefix = InputArgs.getLastArgValue(OBJDUMP_prefix).str();
   parseIntArg(InputArgs, OBJDUMP_prefix_strip, PrefixStrip);
   if (const opt::Arg *A = InputArgs.getLastArg(OBJDUMP_debug_vars_EQ)) {