[clang] [CIR] Fix warnings related to unused variables in release builds (PR #151412)

[Andy Kaylor via cfe-commits]

https://github.com/andykaylor created https://github.com/llvm/llvm-project/pull/151412

This fixes a number of warnings in release builds due to variables that were only being used in asserts. Some of these variables will later be used in non-debug code, but for now they are unused in release builds.

>From ceabe27febbb5bcde8c2f1f887e06a1e21270296 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akaylor at nvidia.com>
Date: Wed, 30 Jul 2025 15:30:18 -0700
Subject: [PATCH] [CIR] Fix warnings related to unused variables in release
 builds

This fixes a number of warnings in release builds due to variables that were
only being used in asserts. Some of these variables will later be used
in non-debug code, but for now they are unused in release builds.
---
 clang/lib/CIR/CodeGen/CIRGenCall.h          | 2 +-
 clang/lib/CIR/CodeGen/CIRGenExpr.cpp        | 5 +++--
 clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp | 3 +++
 clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp  | 2 +-
 clang/lib/CIR/CodeGen/CIRGenFunction.cpp    | 2 +-
 clang/lib/CIR/CodeGen/CIRGenModule.cpp      | 4 +---
 clang/lib/CIR/CodeGen/CIRGenStmt.cpp        | 4 ++--
 7 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenCall.h b/clang/lib/CIR/CodeGen/CIRGenCall.h
index a78956b4df887..28576a15068fa 100644
--- a/clang/lib/CIR/CodeGen/CIRGenCall.h
+++ b/clang/lib/CIR/CodeGen/CIRGenCall.h
@@ -137,7 +137,7 @@ struct CallArg {
 
   /// A data-flow flag to make sure getRValue and/or copyInto are not
   /// called twice for duplicated IR emission.
-  mutable bool isUsed;
+  [[maybe_unused]] mutable bool isUsed;
 
 public:
   clang::QualType ty;
diff --git a/clang/lib/CIR/CodeGen/CIRGenExpr.cpp b/clang/lib/CIR/CodeGen/CIRGenExpr.cpp
index c18498f80e99f..1ff3a206bca27 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExpr.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExpr.cpp
@@ -1472,9 +1472,10 @@ Address CIRGenFunction::emitArrayToPointerDecay(const Expr *e) {
   if (e->getType()->isVariableArrayType())
     return addr;
 
-  auto pointeeTy = mlir::cast<cir::ArrayType>(lvalueAddrTy.getPointee());
+  [[maybe_unused]] auto pointeeTy =
+      mlir::cast<cir::ArrayType>(lvalueAddrTy.getPointee());
 
-  mlir::Type arrayTy = convertType(e->getType());
+  [[maybe_unused]] mlir::Type arrayTy = convertType(e->getType());
   assert(mlir::isa<cir::ArrayType>(arrayTy) && "expected array");
   assert(pointeeTy == arrayTy);
 
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
index 18d2860030a6d..858d8adca97bc 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
@@ -154,12 +154,15 @@ class ComplexExprEmitter : public StmtVisitor<ComplexExprEmitter, mlir::Value> {
 };
 } // namespace
 
+#ifndef NDEBUG
+// Only used in asserts
 static const ComplexType *getComplexType(QualType type) {
   type = type.getCanonicalType();
   if (const ComplexType *comp = dyn_cast<ComplexType>(type))
     return comp;
   return cast<ComplexType>(cast<AtomicType>(type)->getValueType());
 }
+#endif // NDEBUG
 
 LValue ComplexExprEmitter::emitBinAssignLValue(const BinaryOperator *e,
                                                mlir::Value &value) {
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 2523b0ff33787..f62be49ee7af3 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -439,7 +439,7 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
       value = builder.getTrue(cgf.getLoc(e->getExprLoc()));
     } else if (type->isIntegerType()) {
       QualType promotedType;
-      bool canPerformLossyDemotionCheck = false;
+      [[maybe_unused]] bool canPerformLossyDemotionCheck = false;
       if (cgf.getContext().isPromotableIntegerType(type)) {
         promotedType = cgf.getContext().getPromotedIntegerType(type);
         assert(promotedType != type && "Shouldn't promote to the same type.");
diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
index c65d0254bf8e6..a9643ba08164c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenFunction.cpp
@@ -216,7 +216,7 @@ void CIRGenFunction::emitAndUpdateRetAlloca(QualType type, mlir::Location loc,
 void CIRGenFunction::declare(mlir::Value addrVal, const Decl *var, QualType ty,
                              mlir::Location loc, CharUnits alignment,
                              bool isParam) {
-  const auto *namedVar = dyn_cast_or_null<NamedDecl>(var);
+  [[maybe_unused]] const auto *namedVar = dyn_cast_or_null<NamedDecl>(var);
   assert(namedVar && "Needs a named decl");
   assert(!cir::MissingFeatures::cgfSymbolTable());
 
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 623b84f031c13..192e10b698d4d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -656,8 +656,6 @@ mlir::Value CIRGenModule::getAddrOfGlobalVar(const VarDecl *d, mlir::Type ty,
 
 void CIRGenModule::emitGlobalVarDefinition(const clang::VarDecl *vd,
                                            bool isTentative) {
-  const QualType astTy = vd->getType();
-
   if (getLangOpts().OpenCL || getLangOpts().OpenMPIsTargetDevice) {
     errorNYI(vd->getSourceRange(), "emit OpenCL/OpenMP global variable");
     return;
@@ -701,7 +699,7 @@ void CIRGenModule::emitGlobalVarDefinition(const clang::VarDecl *vd,
     // never attempt to emit a tentative definition if a real one
     // exists. A use may still exists, however, so we still may need
     // to do a RAUW.
-    assert(!astTy->isIncompleteType() && "Unexpected incomplete type");
+    assert(!vd->getType()->isIncompleteType() && "Unexpected incomplete type");
     init = builder.getZeroInitAttr(convertType(vd->getType()));
   } else {
     emitter.emplace(*this);
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index 21bee3312eb0f..77f1b13325cec 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -80,12 +80,12 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
 #include "clang/AST/StmtNodes.inc"
     {
       // Remember the block we came in on.
-      mlir::Block *incoming = builder.getInsertionBlock();
+      [[maybe_unused]] mlir::Block *incoming = builder.getInsertionBlock();
       assert(incoming && "expression emission must have an insertion point");
 
       emitIgnoredExpr(cast<Expr>(s));
 
-      mlir::Block *outgoing = builder.getInsertionBlock();
+      [[maybe_unused]] mlir::Block *outgoing = builder.getInsertionBlock();
       assert(outgoing && "expression emission cleared block!");
       return mlir::success();
     }