[clang] aa5bcff - [CIR] Implement part of ConstantExpr support for ScalarExpr (#173009)

[via cfe-commits]

Author: Amr Hesham
Date: 2026-01-06T19:18:23+01:00
New Revision: aa5bcffa06aa5750121a0c4ff418fa66940deffe

URL: https://github.com/llvm/llvm-project/commit/aa5bcffa06aa5750121a0c4ff418fa66940deffe
DIFF: https://github.com/llvm/llvm-project/commit/aa5bcffa06aa5750121a0c4ff418fa66940deffe.diff

LOG: [CIR] Implement part of ConstantExpr support for ScalarExpr (#173009)

Implement part of the ConstantExpr support for the ScalarExpr

Added: 
    

Modified: 
    clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
    clang/test/CIR/CodeGen/constant-expr.cpp

Removed: 
    


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diff  --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index a06f1f1dc1784..70be8977af37a 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -141,6 +141,22 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
   }
 
   mlir::Value VisitConstantExpr(ConstantExpr *e) {
+    // A constant expression of type 'void' generates no code and produces no
+    // value.
+    if (e->getType()->isVoidType())
+      return {};
+
+    if (mlir::Attribute result = ConstantEmitter(cgf).tryEmitConstantExpr(e)) {
+      if (e->isGLValue()) {
+        cgf.cgm.errorNYI(e->getSourceRange(),
+                         "ScalarExprEmitter: constant expr GL Value");
+        return {};
+      }
+
+      return builder.getConstant(cgf.getLoc(e->getSourceRange()),
+                                 mlir::cast<mlir::TypedAttr>(result));
+    }
+
     cgf.cgm.errorNYI(e->getSourceRange(), "ScalarExprEmitter: constant expr");
     return {};
   }

diff  --git a/clang/test/CIR/CodeGen/constant-expr.cpp b/clang/test/CIR/CodeGen/constant-expr.cpp
index b6120ae73f3ea..492cfc5b8fbe2 100644
--- a/clang/test/CIR/CodeGen/constant-expr.cpp
+++ b/clang/test/CIR/CodeGen/constant-expr.cpp
@@ -7,25 +7,37 @@
 
 struct StructWithConstEval {
   consteval int _Complex consteval_ret_complex() { return {1, 2}; }
+  consteval int consteval_ret_int() { return 1; }
+  consteval void consteval_ret_void() {}
 };
 
 void calling_consteval_methods() {
   StructWithConstEval a;
+  int b = a.consteval_ret_int();
   int _Complex c = a.consteval_ret_complex();
+  a.consteval_ret_void();
 }
 
 // CIR: %[[A_ADDR:.*]] = cir.alloca !rec_StructWithConstEval, !cir.ptr<!rec_StructWithConstEval>, ["a"]
+// CIR: %[[B_ADDR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["b", init]
 // CIR: %[[C_ADDR:.*]] = cir.alloca !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>, ["c", init]
+// CIR: %[[CONST_1:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store {{.*}} %[[CONST_1]], %[[B_ADDR]] : !s32i, !cir.ptr<!s32i>
 // CIR: %[[CONST_COMPLEX:.*]] = cir.const #cir.const_complex<#cir.int<1> : !s32i, #cir.int<2> : !s32i> : !cir.complex<!s32i>
 // CIR: cir.store {{.*}} %[[CONST_COMPLEX]], %[[C_ADDR]] : !cir.complex<!s32i>, !cir.ptr<!cir.complex<!s32i>>
 
 // LLVM: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, i64 1, align 1
+// LLVM: %[[B_ADDR:.*]] = alloca i32, i64 1, align 4
 // LLVM: %[[C_ADDR:.*]] = alloca { i32, i32 }, i64 1, align 4
+// LLVM: store i32 1, ptr %[[B_ADDR]], align 4
 // LLVM: store { i32, i32 } { i32 1, i32 2 }, ptr %[[C_ADDR]], align 4
 
 // OGCG: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, align 1
+// OGCG: %[[B_ADDR:.*]] = alloca i32, align 4
 // OGCG: %[[C_ADDR:.*]] = alloca { i32, i32 }, align 4
+// OGCG: store i32 1, ptr %[[B_ADDR]], align 4
 // OGCG: %[[C_REAL_PTR:.*]] = getelementptr inbounds nuw { i32, i32 }, ptr %[[C_ADDR]], i32 0, i32 0
 // OGCG: %[[C_IMAG_PTR:.*]] = getelementptr inbounds nuw { i32, i32 }, ptr %[[C_ADDR]], i32 0, i32 1
 // OGCG: store i32 1, ptr %[[C_REAL_PTR]], align 4
 // OGCG: store i32 2, ptr %[[C_IMAG_PTR]], align 4
+