[CIR] Fix warnings related to unused variables in release builds #151412

andykaylor · 2025-07-30T22:46:47Z

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.

llvmbot · 2025-07-30T22:47:18Z

@llvm/pr-subscribers-clangir

Author: Andy Kaylor (andykaylor)

Changes

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.

Full diff: https://github.com/llvm/llvm-project/pull/151412.diff

7 Files Affected:

(modified) clang/lib/CIR/CodeGen/CIRGenCall.h (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenExpr.cpp (+3-2)
(modified) clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp (+3)
(modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenFunction.cpp (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenModule.cpp (+1-3)
(modified) clang/lib/CIR/CodeGen/CIRGenStmt.cpp (+2-2)

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();
     }

llvmbot · 2025-07-30T22:47:18Z

@llvm/pr-subscribers-clang

Author: Andy Kaylor (andykaylor)

Changes

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.

Full diff: https://github.com/llvm/llvm-project/pull/151412.diff

7 Files Affected:

(modified) clang/lib/CIR/CodeGen/CIRGenCall.h (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenExpr.cpp (+3-2)
(modified) clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp (+3)
(modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenFunction.cpp (+1-1)
(modified) clang/lib/CIR/CodeGen/CIRGenModule.cpp (+1-3)
(modified) clang/lib/CIR/CodeGen/CIRGenStmt.cpp (+2-2)

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();
     }

andykaylor · 2025-07-30T22:47:12Z

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;


Ironic, isn't it?

andykaylor · 2025-07-30T22:49:52Z

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 =


These could be sunk into the asserts, but the expressions would need to be repeated. I was on the fence about which way to go.

andykaylor · 2025-07-30T22:50:24Z

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;


This is written to but never read. It will be read when sanitizer support is added.

andykaylor · 2025-07-30T22:55:13Z

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();


Classic codegen uses these to erase the outgoing block if it doesn't match the incoming block and isn't used. The incubator doesn't do that, perhaps because the canonicalize pass will erase it.

andykaylor · 2025-07-30T22:56:14Z

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);


The assert can be rewritten to eliminate this one. I didn't notice that until now.

…needed.

xlauko · 2025-07-31T11:46:54Z

clang/lib/CIR/CodeGen/CIRGenFunction.cpp

@@ -216,8 +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);
-  assert(namedVar && "Needs a named decl");
+  assert(mlir::isa<NamedDecl>(var) && "Needs a named decl");


This is not mlir thing:

Suggested change

assert(mlir::isa<NamedDecl>(var) && "Needs a named decl");

assert(isa<NamedDecl>(var) && "Needs a named decl");

xlauko

lgtm, with minor nit

[CIR] Fix warnings related to unused variables in release builds

ceabe27

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.

andykaylor requested review from xlauko, bcardosolopes, mmha, erichkeane and lanza July 30, 2025 22:46

llvmbot added clang Clang issues not falling into any other category ClangIR Anything related to the ClangIR project labels Jul 30, 2025

andykaylor commented Jul 30, 2025

View reviewed changes

andykaylor added 2 commits July 30, 2025 15:58

Fold namedVar into the assert.

5fa2289

Remove unused incoming and outgoing vars. Comment on why they aren't …

bd8f03b

…needed.

xlauko approved these changes Jul 31, 2025

View reviewed changes

xlauko reviewed Jul 31, 2025

View reviewed changes

erichkeane approved these changes Jul 31, 2025

View reviewed changes

Fix bad namespacer

c794a25

andykaylor merged commit ba2edbd into llvm:main Jul 31, 2025
9 checks passed

andykaylor deleted the fix-unused branch July 31, 2025 21:55

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[CIR] Fix warnings related to unused variables in release builds #151412

[CIR] Fix warnings related to unused variables in release builds #151412

Uh oh!

andykaylor commented Jul 30, 2025

Uh oh!

llvmbot commented Jul 30, 2025

Uh oh!

llvmbot commented Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Uh oh!

xlauko Jul 31, 2025

Uh oh!

xlauko left a comment

Uh oh!

Uh oh!

Uh oh!

	assert(mlir::isa<NamedDecl>(var) && "Needs a named decl");
	assert(isa<NamedDecl>(var) && "Needs a named decl");

[CIR] Fix warnings related to unused variables in release builds #151412

[CIR] Fix warnings related to unused variables in release builds #151412

Uh oh!

Conversation

andykaylor commented Jul 30, 2025

Uh oh!

llvmbot commented Jul 30, 2025

Uh oh!

llvmbot commented Jul 30, 2025

Uh oh!

andykaylor Jul 30, 2025

Choose a reason for hiding this comment

Uh oh!

andykaylor Jul 30, 2025

Choose a reason for hiding this comment

Uh oh!

andykaylor Jul 30, 2025

Choose a reason for hiding this comment

Uh oh!

andykaylor Jul 30, 2025

Choose a reason for hiding this comment

Uh oh!

andykaylor Jul 30, 2025

Choose a reason for hiding this comment

Uh oh!

xlauko Jul 31, 2025

Choose a reason for hiding this comment

Uh oh!

xlauko left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!