[CIR] Implement part of ConstantExpr support for ScalarExpr

[AmrDeveloper]

Implement part of the ConstantExpr support for the ScalarExpr

[llvmbot]

@llvm/pr-subscribers-clangir

Author: Amr Hesham (AmrDeveloper)

Changes

Implement part of the ConstantExpr support for the ScalarExpr

---

Full diff: https://github.com/llvm/llvm-project/pull/173009.diff

2 Files Affected:

• (modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+17)
• (added) clang/test/CIR/CodeGen/constant-expr.cpp (+30)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index dbd67b367ec4c..cc4048b5aa021 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -141,6 +141,23 @@ 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
new file mode 100644
index 0000000000000..e3325782b6fa3
--- /dev/null
+++ b/clang/test/CIR/CodeGen/constant-expr.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+struct StructWithConstEval {
+  consteval int consteval_ret_int() { return 1; }
+  consteval void consteval_ret_void() {}
+};
+
+void calling_consteval_methods() {
+  StructWithConstEval a;
+  int b = a.consteval_ret_int();
+  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: %[[CONST_1:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store {{.*}} %[[CONST_1]], %[[B_ADDR]] : !s32i, !cir.ptr<!s32i>
+
+// LLVM: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, i64 1, align 1
+// LLVM: %[[B_ADDR:.*]] = alloca i32, i64 1, align 4
+// LLVM: store i32 1, ptr %[[B_ADDR]], align 4
+
+// OGCG: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, align 1
+// OGCG: %[[B_ADDR:.*]] = alloca i32, align 4
+// OGCG: store i32 1, ptr %[[B_ADDR]], align 4

[llvmbot]

@llvm/pr-subscribers-clang

Author: Amr Hesham (AmrDeveloper)

Changes

Implement part of the ConstantExpr support for the ScalarExpr

---

Full diff: https://github.com/llvm/llvm-project/pull/173009.diff

2 Files Affected:

• (modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+17)
• (added) clang/test/CIR/CodeGen/constant-expr.cpp (+30)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index dbd67b367ec4c..cc4048b5aa021 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -141,6 +141,23 @@ 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
new file mode 100644
index 0000000000000..e3325782b6fa3
--- /dev/null
+++ b/clang/test/CIR/CodeGen/constant-expr.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+struct StructWithConstEval {
+  consteval int consteval_ret_int() { return 1; }
+  consteval void consteval_ret_void() {}
+};
+
+void calling_consteval_methods() {
+  StructWithConstEval a;
+  int b = a.consteval_ret_int();
+  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: %[[CONST_1:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store {{.*}} %[[CONST_1]], %[[B_ADDR]] : !s32i, !cir.ptr<!s32i>
+
+// LLVM: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, i64 1, align 1
+// LLVM: %[[B_ADDR:.*]] = alloca i32, i64 1, align 4
+// LLVM: store i32 1, ptr %[[B_ADDR]], align 4
+
+// OGCG: %[[A_ADDR:.*]] = alloca %struct.StructWithConstEval, align 1
+// OGCG: %[[B_ADDR:.*]] = alloca i32, align 4
+// OGCG: store i32 1, ptr %[[B_ADDR]], align 4