diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index feaf92ad4415f..32488d5bfe1ec 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -800,6 +800,7 @@ Crash and bug fixes
   containing a single colon. (#GH167905)
 - Fixed a crash when parsing malformed #pragma clang loop vectorize_width(4,8,16)
   by diagnosing invalid comma-separated argument lists. (#GH166325)
+- Fixed a crash when explicitly casting a complex type to or from an atomic complex type. (#GH172208)
 
 Improvements
 ^^^^^^^^^^^^
diff --git a/clang/lib/CodeGen/CGExprComplex.cpp b/clang/lib/CodeGen/CGExprComplex.cpp
index e5815ef1130dc..151b9473eb39c 100644
--- a/clang/lib/CodeGen/CGExprComplex.cpp
+++ b/clang/lib/CodeGen/CGExprComplex.cpp
@@ -515,7 +515,12 @@ ComplexPairTy ComplexExprEmitter::EmitComplexToComplexCast(ComplexPairTy Val,
                                                            QualType DestType,
                                                            SourceLocation Loc) {
   // Get the src/dest element type.
+  if (SrcType->isAtomicType())
+    SrcType = SrcType->castAs<AtomicType>()->getValueType();
   SrcType = SrcType->castAs<ComplexType>()->getElementType();
+
+  if (DestType->isAtomicType())
+    DestType = DestType->castAs<AtomicType>()->getValueType();
   DestType = DestType->castAs<ComplexType>()->getElementType();
 
   // C99 6.3.1.6: When a value of complex type is converted to another
diff --git a/clang/test/CodeGen/complex.c b/clang/test/CodeGen/complex.c
index 91fc9dda72f72..f0e0709755538 100644
--- a/clang/test/CodeGen/complex.c
+++ b/clang/test/CodeGen/complex.c
@@ -593,3 +593,87 @@ void imag_on_scalar_with_type_promotion() {
   _Float16 _Complex a;
   _Float16 b = __real__(__imag__ a);
 }
+
+// CHECK-LABEL: define dso_local void @explicit_cast_atomic_complex_to_atomic_complex(
+// CHECK-SAME: ) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[A:%.*]] = alloca { float, float }, align 8
+// CHECK-NEXT:    [[B:%.*]] = alloca { i32, i32 }, align 8
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca { float, float }, align 8
+// CHECK-NEXT:    [[A_REALP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 0
+// CHECK-NEXT:    [[A_IMAGP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 1
+// CHECK-NEXT:    store float 2.000000e+00, ptr [[A_REALP]], align 8
+// CHECK-NEXT:    store float 0.000000e+00, ptr [[A_IMAGP]], align 4
+// CHECK-NEXT:    [[ATOMIC_LOAD:%.*]] = load atomic i64, ptr [[A]] seq_cst, align 8
+// CHECK-NEXT:    store i64 [[ATOMIC_LOAD]], ptr [[ATOMIC_TEMP]], align 8
+// CHECK-NEXT:    [[ATOMIC_TEMP_REALP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[ATOMIC_TEMP]], i32 0, i32 0
+// CHECK-NEXT:    [[ATOMIC_TEMP_REAL:%.*]] = load float, ptr [[ATOMIC_TEMP_REALP]], align 8
+// CHECK-NEXT:    [[ATOMIC_TEMP_IMAGP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[ATOMIC_TEMP]], i32 0, i32 1
+// CHECK-NEXT:    [[ATOMIC_TEMP_IMAG:%.*]] = load float, ptr [[ATOMIC_TEMP_IMAGP]], align 4
+// CHECK-NEXT:    [[CONV:%.*]] = fptosi float [[ATOMIC_TEMP_REAL]] to i32
+// CHECK-NEXT:    [[CONV1:%.*]] = fptosi float [[ATOMIC_TEMP_IMAG]] to i32
+// CHECK-NEXT:    [[B_REALP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 0
+// CHECK-NEXT:    [[B_IMAGP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 1
+// CHECK-NEXT:    store i32 [[CONV]], ptr [[B_REALP]], align 8
+// CHECK-NEXT:    store i32 [[CONV1]], ptr [[B_IMAGP]], align 4
+// CHECK-NEXT:    ret void
+//
+void explicit_cast_atomic_complex_to_atomic_complex() {
+  _Atomic _Complex float a = 2.0f;
+  _Atomic _Complex int b = (_Atomic _Complex int)a;
+}
+
+// CHECK-LABEL: define dso_local void @explicit_cast_atomic_complex_to_complex(
+// CHECK-SAME: ) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[A:%.*]] = alloca { float, float }, align 8
+// CHECK-NEXT:    [[B:%.*]] = alloca { i32, i32 }, align 4
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca { float, float }, align 8
+// CHECK-NEXT:    [[A_REALP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 0
+// CHECK-NEXT:    [[A_IMAGP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 1
+// CHECK-NEXT:    store float 2.000000e+00, ptr [[A_REALP]], align 8
+// CHECK-NEXT:    store float 0.000000e+00, ptr [[A_IMAGP]], align 4
+// CHECK-NEXT:    [[ATOMIC_LOAD:%.*]] = load atomic i64, ptr [[A]] seq_cst, align 8
+// CHECK-NEXT:    store i64 [[ATOMIC_LOAD]], ptr [[ATOMIC_TEMP]], align 8
+// CHECK-NEXT:    [[ATOMIC_TEMP_REALP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[ATOMIC_TEMP]], i32 0, i32 0
+// CHECK-NEXT:    [[ATOMIC_TEMP_REAL:%.*]] = load float, ptr [[ATOMIC_TEMP_REALP]], align 8
+// CHECK-NEXT:    [[ATOMIC_TEMP_IMAGP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[ATOMIC_TEMP]], i32 0, i32 1
+// CHECK-NEXT:    [[ATOMIC_TEMP_IMAG:%.*]] = load float, ptr [[ATOMIC_TEMP_IMAGP]], align 4
+// CHECK-NEXT:    [[CONV:%.*]] = fptosi float [[ATOMIC_TEMP_REAL]] to i32
+// CHECK-NEXT:    [[CONV1:%.*]] = fptosi float [[ATOMIC_TEMP_IMAG]] to i32
+// CHECK-NEXT:    [[B_REALP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 0
+// CHECK-NEXT:    [[B_IMAGP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 1
+// CHECK-NEXT:    store i32 [[CONV]], ptr [[B_REALP]], align 4
+// CHECK-NEXT:    store i32 [[CONV1]], ptr [[B_IMAGP]], align 4
+// CHECK-NEXT:    ret void
+//
+void explicit_cast_atomic_complex_to_complex() {
+  _Atomic _Complex float a = 2.0f;
+  _Complex int b = (_Complex int)a;
+}
+
+// CHECK-LABEL: define dso_local void @explicit_cast_complex_to_atomic_complex(
+// CHECK-SAME: ) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[A:%.*]] = alloca { float, float }, align 4
+// CHECK-NEXT:    [[B:%.*]] = alloca { i32, i32 }, align 8
+// CHECK-NEXT:    [[A_REALP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 0
+// CHECK-NEXT:    [[A_IMAGP:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 1
+// CHECK-NEXT:    store float 2.000000e+00, ptr [[A_REALP]], align 4
+// CHECK-NEXT:    store float 0.000000e+00, ptr [[A_IMAGP]], align 4
+// CHECK-NEXT:    [[A_REALP1:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 0
+// CHECK-NEXT:    [[A_REAL:%.*]] = load float, ptr [[A_REALP1]], align 4
+// CHECK-NEXT:    [[A_IMAGP2:%.*]] = getelementptr inbounds nuw { float, float }, ptr [[A]], i32 0, i32 1
+// CHECK-NEXT:    [[A_IMAG:%.*]] = load float, ptr [[A_IMAGP2]], align 4
+// CHECK-NEXT:    [[CONV:%.*]] = fptosi float [[A_REAL]] to i32
+// CHECK-NEXT:    [[CONV3:%.*]] = fptosi float [[A_IMAG]] to i32
+// CHECK-NEXT:    [[B_REALP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 0
+// CHECK-NEXT:    [[B_IMAGP:%.*]] = getelementptr inbounds nuw { i32, i32 }, ptr [[B]], i32 0, i32 1
+// CHECK-NEXT:    store i32 [[CONV]], ptr [[B_REALP]], align 8
+// CHECK-NEXT:    store i32 [[CONV3]], ptr [[B_IMAGP]], align 4
+// CHECK-NEXT:    ret void
+//
+void explicit_cast_complex_to_atomic_complex() {
+  _Complex float a = 2.0f;
+  _Atomic _Complex int b = (_Atomic _Complex int)a;
+}