llvm · jhuber6 · Sep 12, 2025
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
@@ -9385,11 +9385,21 @@ AssignConvertType Sema::CheckAssignmentConstraints(QualType LHSType,
     return AssignConvertType::Incompatible;
   }
 
-  // Allow scalar to ExtVector assignments, and assignments of an ExtVector type
-  // to the same ExtVector type.
-  if (LHSType->isExtVectorType()) {
-    if (RHSType->isExtVectorType())
+  // Allow scalar to ExtVector assignments, assignment to bool, and assignments
+  // of an ExtVector type to the same ExtVector type.
+  if (auto *LHSExtType = LHSType->getAs<ExtVectorType>()) {
+    if (auto *RHSExtType = RHSType->getAs<ExtVectorType>()) {
+      // Implicit conversions require the same number of elements.
+      if (LHSExtType->getNumElements() != RHSExtType->getNumElements())
+        return AssignConvertType::Incompatible;
+
+      if (LHSType->isExtVectorBoolType() &&
+          RHSExtType->getElementType()->isIntegerType()) {
+        Kind = CK_IntegralToBoolean;
+        return AssignConvertType::Compatible;
+      }
       return AssignConvertType::Incompatible;
+    }
     if (RHSType->isArithmeticType()) {
       // CK_VectorSplat does T -> vector T, so first cast to the element type.
       if (ConvertRHS)

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
@@ -2162,9 +2162,18 @@ static bool IsVectorConversion(Sema &S, QualType FromType, QualType ToType,
 
   // There are no conversions between extended vector types, only identity.
   if (auto *ToExtType = ToType->getAs<ExtVectorType>()) {
-    if (FromType->getAs<ExtVectorType>()) {
-      // There are no conversions between extended vector types other than the
-      // identity conversion.
+    if (auto *FromExtType = FromType->getAs<ExtVectorType>()) {
+      // Implicit conversions require the same number of elements.
+      if (ToExtType->getNumElements() != FromExtType->getNumElements())
+        return false;
+
+      // Permit implicit conversions from integral values to boolean vectors.
+      if (ToType->isExtVectorBoolType() &&
+          FromExtType->getElementType()->isIntegerType()) {
+        ICK = ICK_Boolean_Conversion;
+        return true;
+      }
+      // There are no other conversions between extended vector types.
       return false;
     }
 

diff --git a/clang/test/CodeGen/vector-convert-boolean.cpp b/clang/test/CodeGen/vector-convert-boolean.cpp
@@ -0,0 +1,70 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -emit-llvm -o - | FileCheck %s
+
+using v1i = int [[clang::ext_vector_type(1)]];
+using v1b = bool [[clang::ext_vector_type(1)]];
+using v8i = int [[clang::ext_vector_type(8)]];
+using v8b = bool [[clang::ext_vector_type(8)]];
+using v16i = short [[clang::ext_vector_type(16)]];
+using v16b = bool [[clang::ext_vector_type(16)]];
+using v32i = char [[clang::ext_vector_type(32)]];
+using v32b = bool [[clang::ext_vector_type(32)]];
+
+// CHECK-LABEL: define dso_local noundef i8 @_Z3fooDv1_i(
+// CHECK-SAME: i32 noundef [[V_COERCE:%.*]]) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[RETVAL:%.*]] = alloca <1 x i1>, align 1
+// CHECK-NEXT:    [[V:%.*]] = alloca <1 x i32>, align 4
+// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca <1 x i32>, align 4
+// CHECK-NEXT:    store i32 [[V_COERCE]], ptr [[V]], align 4
+// CHECK-NEXT:    [[V1:%.*]] = load <1 x i32>, ptr [[V]], align 4
+// CHECK-NEXT:    store <1 x i32> [[V1]], ptr [[V_ADDR]], align 4
+// CHECK-NEXT:    [[TMP0:%.*]] = load <1 x i32>, ptr [[V_ADDR]], align 4
+// CHECK-NEXT:    [[TOBOOL:%.*]] = icmp ne <1 x i32> [[TMP0]], zeroinitializer
+// CHECK-NEXT:    store <1 x i1> [[TOBOOL]], ptr [[RETVAL]], align 1
+// CHECK-NEXT:    [[TMP1:%.*]] = load i8, ptr [[RETVAL]], align 1
+// CHECK-NEXT:    ret i8 [[TMP1]]
+//
+v1b foo(v1i v) { return v; }
+// CHECK-LABEL: define dso_local noundef i8 @_Z3fooDv8_i(
+// CHECK-SAME: ptr noundef byval(<8 x i32>) align 32 [[TMP0:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[RETVAL:%.*]] = alloca <8 x i1>, align 1
+// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca <8 x i32>, align 32
+// CHECK-NEXT:    [[V:%.*]] = load <8 x i32>, ptr [[TMP0]], align 32
+// CHECK-NEXT:    store <8 x i32> [[V]], ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TMP1:%.*]] = load <8 x i32>, ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TOBOOL:%.*]] = icmp ne <8 x i32> [[TMP1]], zeroinitializer
+// CHECK-NEXT:    store <8 x i1> [[TOBOOL]], ptr [[RETVAL]], align 1
+// CHECK-NEXT:    [[TMP2:%.*]] = load i8, ptr [[RETVAL]], align 1
+// CHECK-NEXT:    ret i8 [[TMP2]]
+//
+v8b foo(v8i v) { return v; }
+// CHECK-LABEL: define dso_local noundef i16 @_Z3fooDv16_s(
+// CHECK-SAME: ptr noundef byval(<16 x i16>) align 32 [[TMP0:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[RETVAL:%.*]] = alloca <16 x i1>, align 2
+// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca <16 x i16>, align 32
+// CHECK-NEXT:    [[V:%.*]] = load <16 x i16>, ptr [[TMP0]], align 32
+// CHECK-NEXT:    store <16 x i16> [[V]], ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TMP1:%.*]] = load <16 x i16>, ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TOBOOL:%.*]] = icmp ne <16 x i16> [[TMP1]], zeroinitializer
+// CHECK-NEXT:    store <16 x i1> [[TOBOOL]], ptr [[RETVAL]], align 2
+// CHECK-NEXT:    [[TMP2:%.*]] = load i16, ptr [[RETVAL]], align 2
+// CHECK-NEXT:    ret i16 [[TMP2]]
+//
+v16b foo(v16i v) { return v; }
+// CHECK-LABEL: define dso_local noundef i32 @_Z3fooDv32_c(
+// CHECK-SAME: ptr noundef byval(<32 x i8>) align 32 [[TMP0:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[RETVAL:%.*]] = alloca <32 x i1>, align 4
+// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca <32 x i8>, align 32
+// CHECK-NEXT:    [[V:%.*]] = load <32 x i8>, ptr [[TMP0]], align 32
+// CHECK-NEXT:    store <32 x i8> [[V]], ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TMP1:%.*]] = load <32 x i8>, ptr [[V_ADDR]], align 32
+// CHECK-NEXT:    [[TOBOOL:%.*]] = icmp ne <32 x i8> [[TMP1]], zeroinitializer
+// CHECK-NEXT:    store <32 x i1> [[TOBOOL]], ptr [[RETVAL]], align 4
+// CHECK-NEXT:    [[TMP2:%.*]] = load i32, ptr [[RETVAL]], align 4
+// CHECK-NEXT:    ret i32 [[TMP2]]
+//
+v32b foo(v32i v) { return v; }
diff --git a/clang/test/Sema/vector-bool-assign.c b/clang/test/Sema/vector-bool-assign.c
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify %s
+
+typedef _Bool bool;
+
+typedef __attribute__((ext_vector_type(8))) int v8i;
+typedef __attribute__((ext_vector_type(8))) bool v8b;
+typedef __attribute__((ext_vector_type(4))) float v4f;
+typedef __attribute__((ext_vector_type(4))) bool v4b;
+
+void foo(v8b);
+
+v8b integral(v8i v) {
+  v8b m1 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) int);
+  v8b m2 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) unsigned);
+  v8b m3 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) long);
+  v8b m4 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) unsigned long);
+  v8b m5 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) char);
+  v8b m6 = __builtin_convertvector(v, __attribute__((ext_vector_type(8))) unsigned char);
+  foo(v);
+  return v;
+}
+
+v4b non_integral(v4f vf) {
+  return vf; // expected-error{{returning 'v4f' (vector of 4 'float' values) from a function with incompatible result type 'v4b' (vector of 4 'bool' values}}
+}
+
+v4b size_mismatch(v8i v) {
+  return v; // expected-error{{returning 'v8i' (vector of 8 'int' values) from a function with incompatible result type 'v4b' (vector of 4 'bool' values)}}
+}
diff --git a/clang/test/Sema/vector-bool-assign.cpp b/clang/test/Sema/vector-bool-assign.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify %s
+
+using v8i = int [[clang::ext_vector_type(8)]];
+using v8b = bool [[clang::ext_vector_type(8)]];
+using v4f = float [[clang::ext_vector_type(4)]];
+using v4b = bool [[clang::ext_vector_type(4)]];
+
+void foo(v8b);
+
+v8b integral(v8i v) {
+  v8b m1 = __builtin_convertvector(v, int [[clang::ext_vector_type(8)]]);
+  v8b m2 = __builtin_convertvector(v, unsigned [[clang::ext_vector_type(8)]]);
+  v8b m3 = __builtin_convertvector(v, long [[clang::ext_vector_type(8)]]);
+  v8b m4 = __builtin_convertvector(v, unsigned long [[clang::ext_vector_type(8)]]);
+  v8b m5 = __builtin_convertvector(v, char [[clang::ext_vector_type(8)]]);
+  v8b m6 = __builtin_convertvector(v, unsigned char [[clang::ext_vector_type(8)]]);
+  foo(v);
+  return v;
+}
+
+v4b non_integral(v4f vf) {
+  return vf; // expected-error{{cannot initialize return object of type 'v4b' (vector of 4 'bool' values) with an lvalue of type 'v4f' (vector of 4 'float' values)}}
+}
+
+v4b size_mismatch(v8i v) {
+  return v; // expected-error{{cannot initialize return object of type 'v4b' (vector of 4 'bool' values) with an lvalue of type 'v8i' (vector of 8 'int' values)}}
+}