[clang] [CIR] Add value initialization for scalar types (PR #156036)

via cfe-commits cfe-commits at lists.llvm.org
Fri Aug 29 07:46:59 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Morris Hafner (mmha)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/156036.diff


2 Files Affected:

- (modified) clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp (+6-3) 
- (modified) clang/test/CIR/CodeGen/local-vars.cpp (+149-45) 


``````````diff
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 46934e7155adf..6b768c5e9d30d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -92,6 +92,10 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
                                             mlir::Value value, CastKind kind,
                                             QualType destTy);
 
+  mlir::Value emitNullValue(QualType ty, mlir::Location loc) {
+    return cgf.cgm.emitNullConstant(ty, loc);
+  }
+
   mlir::Value emitPromotedValue(mlir::Value result, QualType promotionType) {
     return builder.createFloatingCast(result, cgf.convertType(promotionType));
   }
@@ -1967,9 +1971,8 @@ mlir::Value ScalarExprEmitter::VisitInitListExpr(InitListExpr *e) {
   }
 
   if (numInitElements == 0) {
-    cgf.cgm.errorNYI(e->getSourceRange(),
-                     "InitListExpr Non VectorType with 0 init elements");
-    return {};
+    // C++11 value-initialization for the scalar.
+    return emitNullValue(e->getType(), cgf.getLoc(e->getExprLoc()));
   }
 
   return Visit(e->getInit(0));
diff --git a/clang/test/CIR/CodeGen/local-vars.cpp b/clang/test/CIR/CodeGen/local-vars.cpp
index 9385fdfa65601..fc0eea9bc5338 100644
--- a/clang/test/CIR/CodeGen/local-vars.cpp
+++ b/clang/test/CIR/CodeGen/local-vars.cpp
@@ -1,5 +1,9 @@
-// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t-cir.ll
-// RUN: FileCheck -input-file=%t-cir.ll %s
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s --check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s --check-prefix=OGCG
 
 void test() {
   int i = 1;
@@ -21,46 +25,146 @@ void test() {
   bool uib;
 }
 
-// CHECK: module
-// CHECK: cir.func{{.*}} @_Z4testv()
-// CHECK:    %[[I_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["i", init] {alignment = 4 : i64}
-// CHECK:    %[[L_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["l", init] {alignment = 8 : i64}
-// CHECK:    %[[F_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["f", init] {alignment = 4 : i64}
-// CHECK:    %[[D_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["d", init] {alignment = 8 : i64}
-// CHECK:    %[[B1_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["b1", init] {alignment = 1 : i64}
-// CHECK:    %[[B2_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["b2", init] {alignment = 1 : i64}
-// CHECK:    %[[CI_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["ci", init, const] {alignment = 4 : i64}
-// CHECK:    %[[CL_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["cl", init, const] {alignment = 8 : i64}
-// CHECK:    %[[CF_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["cf", init, const] {alignment = 4 : i64}
-// CHECK:    %[[CD_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["cd", init, const] {alignment = 8 : i64}
-// CHECK:    %[[CB1_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["cb1", init, const] {alignment = 1 : i64}
-// CHECK:    %[[CB2_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["cb2", init, const] {alignment = 1 : i64}
-// CHECK:    %[[UII_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["uii"] {alignment = 4 : i64}
-// CHECK:    %[[UIL_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["uil"] {alignment = 8 : i64}
-// CHECK:    %[[UIF_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["uif"] {alignment = 4 : i64}
-// CHECK:    %[[UID_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["uid"] {alignment = 8 : i64}
-// CHECK:    %[[UIB_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["uib"] {alignment = 1 : i64}
-// CHECK:    %[[ONE:.*]] = cir.const #cir.int<1> : !s32i
-// CHECK:    cir.store align(4) %[[ONE]], %[[I_PTR]] : !s32i, !cir.ptr<!s32i>
-// CHECK:    %[[TWO:.*]] = cir.const #cir.int<2> : !s64i
-// CHECK:    cir.store align(8) %[[TWO]], %[[L_PTR]] : !s64i, !cir.ptr<!s64i>
-// CHECK:    %[[THREE:.*]] = cir.const #cir.fp<3.0{{.*}}> : !cir.float
-// CHECK:    cir.store align(4) %[[THREE]], %[[F_PTR]] : !cir.float, !cir.ptr<!cir.float>
-// CHECK:    %[[FOUR:.*]] = cir.const #cir.fp<4.0{{.*}}> : !cir.double
-// CHECK:    cir.store align(8) %[[FOUR]], %[[D_PTR]] : !cir.double, !cir.ptr<!cir.double>
-// CHECK:    %[[TRUE:.*]] = cir.const #true
-// CHECK:    cir.store align(1) %[[TRUE]], %[[B1_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
-// CHECK:    %[[FALSE:.*]] = cir.const #false
-// CHECK:    cir.store align(1) %[[FALSE]], %[[B2_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
-// CHECK:    %[[ONEC:.*]] = cir.const #cir.int<1> : !s32i
-// CHECK:    cir.store align(4) %[[ONEC]], %[[CI_PTR]] : !s32i, !cir.ptr<!s32i>
-// CHECK:    %[[TWOC:.*]] = cir.const #cir.int<2> : !s64i
-// CHECK:    cir.store align(8) %[[TWOC]], %[[CL_PTR]] : !s64i, !cir.ptr<!s64i>
-// CHECK:    %[[THREEC:.*]] = cir.const #cir.fp<3.0{{.*}}> : !cir.float
-// CHECK:    cir.store align(4) %[[THREEC]], %[[CF_PTR]] : !cir.float, !cir.ptr<!cir.float>
-// CHECK:    %[[FOURC:.*]] = cir.const #cir.fp<4.0{{.*}}> : !cir.double
-// CHECK:    cir.store align(8) %[[FOURC]], %[[CD_PTR]] : !cir.double, !cir.ptr<!cir.double>
-// CHECK:    %[[TRUEC:.*]] = cir.const #true
-// CHECK:    cir.store align(1) %[[TRUEC]], %[[CB1_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
-// CHECK:    %[[FALSEC:.*]] = cir.const #false
-// CHECK:    cir.store align(1) %[[FALSEC]], %[[CB2_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+// CIR: module
+// CIR: cir.func{{.*}} @_Z4testv()
+// CIR:    %[[I_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["i", init] {alignment = 4 : i64}
+// CIR:    %[[L_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["l", init] {alignment = 8 : i64}
+// CIR:    %[[F_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["f", init] {alignment = 4 : i64}
+// CIR:    %[[D_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["d", init] {alignment = 8 : i64}
+// CIR:    %[[B1_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["b1", init] {alignment = 1 : i64}
+// CIR:    %[[B2_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["b2", init] {alignment = 1 : i64}
+// CIR:    %[[CI_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["ci", init, const] {alignment = 4 : i64}
+// CIR:    %[[CL_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["cl", init, const] {alignment = 8 : i64}
+// CIR:    %[[CF_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["cf", init, const] {alignment = 4 : i64}
+// CIR:    %[[CD_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["cd", init, const] {alignment = 8 : i64}
+// CIR:    %[[CB1_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["cb1", init, const] {alignment = 1 : i64}
+// CIR:    %[[CB2_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["cb2", init, const] {alignment = 1 : i64}
+// CIR:    %[[UII_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["uii"] {alignment = 4 : i64}
+// CIR:    %[[UIL_PTR:.*]] = cir.alloca !s64i, !cir.ptr<!s64i>, ["uil"] {alignment = 8 : i64}
+// CIR:    %[[UIF_PTR:.*]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["uif"] {alignment = 4 : i64}
+// CIR:    %[[UID_PTR:.*]] = cir.alloca !cir.double, !cir.ptr<!cir.double>, ["uid"] {alignment = 8 : i64}
+// CIR:    %[[UIB_PTR:.*]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["uib"] {alignment = 1 : i64}
+// CIR:    %[[ONE:.*]] = cir.const #cir.int<1> : !s32i
+// CIR:    cir.store align(4) %[[ONE]], %[[I_PTR]] : !s32i, !cir.ptr<!s32i>
+// CIR:    %[[TWO:.*]] = cir.const #cir.int<2> : !s64i
+// CIR:    cir.store align(8) %[[TWO]], %[[L_PTR]] : !s64i, !cir.ptr<!s64i>
+// CIR:    %[[THREE:.*]] = cir.const #cir.fp<3.0{{.*}}> : !cir.float
+// CIR:    cir.store align(4) %[[THREE]], %[[F_PTR]] : !cir.float, !cir.ptr<!cir.float>
+// CIR:    %[[FOUR:.*]] = cir.const #cir.fp<4.0{{.*}}> : !cir.double
+// CIR:    cir.store align(8) %[[FOUR]], %[[D_PTR]] : !cir.double, !cir.ptr<!cir.double>
+// CIR:    %[[TRUE:.*]] = cir.const #true
+// CIR:    cir.store align(1) %[[TRUE]], %[[B1_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+// CIR:    %[[FALSE:.*]] = cir.const #false
+// CIR:    cir.store align(1) %[[FALSE]], %[[B2_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+// CIR:    %[[ONEC:.*]] = cir.const #cir.int<1> : !s32i
+// CIR:    cir.store align(4) %[[ONEC]], %[[CI_PTR]] : !s32i, !cir.ptr<!s32i>
+// CIR:    %[[TWOC:.*]] = cir.const #cir.int<2> : !s64i
+// CIR:    cir.store align(8) %[[TWOC]], %[[CL_PTR]] : !s64i, !cir.ptr<!s64i>
+// CIR:    %[[THREEC:.*]] = cir.const #cir.fp<3.0{{.*}}> : !cir.float
+// CIR:    cir.store align(4) %[[THREEC]], %[[CF_PTR]] : !cir.float, !cir.ptr<!cir.float>
+// CIR:    %[[FOURC:.*]] = cir.const #cir.fp<4.0{{.*}}> : !cir.double
+// CIR:    cir.store align(8) %[[FOURC]], %[[CD_PTR]] : !cir.double, !cir.ptr<!cir.double>
+// CIR:    %[[TRUEC:.*]] = cir.const #true
+// CIR:    cir.store align(1) %[[TRUEC]], %[[CB1_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+// CIR:    %[[FALSEC:.*]] = cir.const #false
+// CIR:    cir.store align(1) %[[FALSEC]], %[[CB2_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+
+// LLVM: define dso_local void @_Z4testv()
+// LLVM:   %[[I_PTR:.+]] = alloca i32
+// LLVM:   %[[L_PTR:.+]] = alloca i64
+// LLVM:   %[[F_PTR:.+]] = alloca float
+// LLVM:   %[[D_PTR:.+]] = alloca double
+// LLVM:   %[[B1_PTR:.+]] = alloca i8
+// LLVM:   %[[B2_PTR:.+]] = alloca i8
+// LLVM:   %[[CI_PTR:.+]] = alloca i32
+// LLVM:   %[[CL_PTR:.+]] = alloca i64
+// LLVM:   %[[CF_PTR:.+]] = alloca float
+// LLVM:   %[[CD_PTR:.+]] = alloca double
+// LLVM:   %[[CB1_PTR:.+]] = alloca i8
+// LLVM:   %[[CB2_PTR:.+]] = alloca i8
+// LLVM:   %[[UII_PTR:.+]] = alloca i32
+// LLVM:   %[[UIL_PTR:.+]] = alloca i64
+// LLVM:   %[[UIF_PTR:.+]] = alloca float
+// LLVM:   %[[UID_PTR:.+]] = alloca double
+// LLVM:   %[[UIB_PTR:.+]] = alloca i8
+// LLVM:   store i32 1, ptr %[[I_PTR]]
+// LLVM:   store i64 2, ptr %[[L_PTR]]
+// LLVM:   store float 3.000000e+00, ptr %[[F_PTR]]
+// LLVM:   store double 4.000000e+00, ptr %[[D_PTR]]
+// LLVM:   store i8 1, ptr %[[B1_PTR]]
+// LLVM:   store i8 0, ptr %[[B2_PTR]]
+// LLVM:   store i32 1, ptr %[[CI_PTR]]
+// LLVM:   store i64 2, ptr %[[CL_PTR]]
+// LLVM:   store float 3.000000e+00, ptr %[[CF_PTR]]
+// LLVM:   store double 4.000000e+00, ptr %[[CD_PTR]]
+// LLVM:   store i8 1, ptr %[[CB1_PTR]]
+// LLVM:   store i8 0, ptr %[[CB2_PTR]]
+// LLVM:   ret void
+
+// OGCG: define dso_local void @_Z4testv()
+// OGCG:   %[[I_PTR:.+]] = alloca i32
+// OGCG:   %[[L_PTR:.+]] = alloca i64
+// OGCG:   %[[F_PTR:.+]] = alloca float
+// OGCG:   %[[D_PTR:.+]] = alloca double
+// OGCG:   %[[B1_PTR:.+]] = alloca i8
+// OGCG:   %[[B2_PTR:.+]] = alloca i8
+// OGCG:   %[[CI_PTR:.+]] = alloca i32
+// OGCG:   %[[CL_PTR:.+]] = alloca i64
+// OGCG:   %[[CF_PTR:.+]] = alloca float
+// OGCG:   %[[CD_PTR:.+]] = alloca double
+// OGCG:   %[[CB1_PTR:.+]] = alloca i8
+// OGCG:   %[[CB2_PTR:.+]] = alloca i8
+// OGCG:   %[[UII_PTR:.+]] = alloca i32
+// OGCG:   %[[UIL_PTR:.+]] = alloca i64
+// OGCG:   %[[UIF_PTR:.+]] = alloca float
+// OGCG:   %[[UID_PTR:.+]] = alloca double
+// OGCG:   %[[UIB_PTR:.+]] = alloca i8
+// OGCG:   store i32 1, ptr %[[I_PTR]]
+// OGCG:   store i64 2, ptr %[[L_PTR]]
+// OGCG:   store float 3.000000e+00, ptr %[[F_PTR]]
+// OGCG:   store double 4.000000e+00, ptr %[[D_PTR]]
+// OGCG:   store i8 1, ptr %[[B1_PTR]]
+// OGCG:   store i8 0, ptr %[[B2_PTR]]
+// OGCG:   store i32 1, ptr %[[CI_PTR]]
+// OGCG:   store i64 2, ptr %[[CL_PTR]]
+// OGCG:   store float 3.000000e+00, ptr %[[CF_PTR]]
+// OGCG:   store double 4.000000e+00, ptr %[[CD_PTR]]
+// OGCG:   store i8 1, ptr %[[CB1_PTR]]
+// OGCG:   store i8 0, ptr %[[CB2_PTR]]
+// OGCG:   ret void
+
+void value_init() {
+  float f{};
+  bool b{};
+  int i{};
+}
+
+// CIR: cir.func{{.*}} @_Z10value_initv()
+// CIR:   %[[F_PTR:.+]] = cir.alloca !cir.float, !cir.ptr<!cir.float>, ["f", init]
+// CIR:   %[[B_PTR:.+]] = cir.alloca !cir.bool, !cir.ptr<!cir.bool>, ["b", init]
+// CIR:   %[[I_PTR:.+]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["i", init]
+// CIR:   %[[ZEROF:.+]] = cir.const #cir.fp<0.000000e+00> : !cir.float
+// CIR:   cir.store {{.*}} %[[ZEROF]], %[[F_PTR]] : !cir.float, !cir.ptr<!cir.float>
+// CIR:   %[[FALSE:.+]] = cir.const #false
+// CIR:   cir.store {{.*}} %[[FALSE]], %[[B_PTR]] : !cir.bool, !cir.ptr<!cir.bool>
+// CIR:   %[[ZEROI:.+]] = cir.const #cir.int<0> : !s32i
+// CIR:   cir.store {{.*}} %[[ZEROI]], %[[I_PTR]] : !s32i, !cir.ptr<!s32i>
+// CIR:   cir.return
+
+// LLVM: define dso_local void @_Z10value_initv()
+// LLVM:   %[[F_PTR:.+]] = alloca float
+// LLVM:   %[[B_PTR:.+]] = alloca i8
+// LLVM:   %[[I_PTR:.+]] = alloca i32
+// LLVM:   store float 0.000000e+00, ptr %[[F_PTR]]
+// LLVM:   store i8 0, ptr %[[B_PTR]]
+// LLVM:   store i32 0, ptr %[[I_PTR]]
+// LLVM:   ret void
+
+// OGCG: define dso_local void @_Z10value_initv()
+// OGCG:   %[[F_PTR:.+]] = alloca float
+// OGCG:   %[[B_PTR:.+]] = alloca i8
+// OGCG:   %[[I_PTR:.+]] = alloca i32
+// OGCG:   store float 0.000000e+00, ptr %[[F_PTR]]
+// OGCG:   store i8 0, ptr %[[B_PTR]]
+// OGCG:   store i32 0, ptr %[[I_PTR]]
+// OGCG:   ret void

``````````

</details>


https://github.com/llvm/llvm-project/pull/156036


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