[CIR] Upstream zero init for global variables (#133100)

This change adds zero initialization for global variables

1 files changed, 5 insertions, 2 deletions

diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 9776a4e..2a37d6c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -140,17 +140,20 @@ void CIRGenModule::emitGlobalVarDefinition(const clang::VarDecl *vd,
     // certain constant expressions is implemented for now.
     const VarDecl *initDecl;
     const Expr *initExpr = vd->getAnyInitializer(initDecl);
+    mlir::Attribute initializer;
     if (initExpr) {
-      mlir::Attribute initializer;
       if (APValue *value = initDecl->evaluateValue()) {
         ConstantEmitter emitter(*this);
         initializer = emitter.tryEmitPrivateForMemory(*value, astTy);
       } else {
         errorNYI(initExpr->getSourceRange(), "non-constant initializer");
       }
-      varOp.setInitialValueAttr(initializer);
+    } else {
+      initializer = builder.getZeroInitAttr(convertType(astTy));
     }
 
+    varOp.setInitialValueAttr(initializer);
+
     // Set CIR's linkage type as appropriate.
     cir::GlobalLinkageKind linkage =
         getCIRLinkageVarDefinition(vd, /*IsConstant=*/false);