diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -837,7 +837,9 @@
       E = ImpCastExprToType(E, PTy, CK_IntegralCast).get();
       return E;
     }
-    if (Ty->isPromotableIntegerType()) {
+    if (Ty->isPromotableIntegerType() &&
+        // Avoid promote integer type to int.
+        !getLangOpts().HLSL) {
       QualType PT = Context.getPromotedIntegerType(Ty);
       E = ImpCastExprToType(E, PT, CK_IntegralCast).get();
       return E;
diff --git a/clang/test/CodeGenHLSL/basic_types.hlsl b/clang/test/CodeGenHLSL/basic_types.hlsl
--- a/clang/test/CodeGenHLSL/basic_types.hlsl
+++ b/clang/test/CodeGenHLSL/basic_types.hlsl
@@ -4,7 +4,7 @@
 
 
 // CHECK:"?uint16_t_Val@@3GA" = global i16 0, align 2
-// CHECK:"?int16_t_Val@@3FA" = global i16 0, align 2
+// CHECK:"?int16_t_Val@@3FA" = global i16 0
 // CHECK:"?uint_Val@@3IA" = global i32 0, align 4
 // CHECK:"?uint64_t_Val@@3KA" = global i64 0, align 8
 // CHECK:"?int64_t_Val@@3JA" = global i64 0, align 8
diff --git a/clang/test/CodeGenHLSL/builtins/abs.hlsl b/clang/test/CodeGenHLSL/builtins/abs.hlsl
--- a/clang/test/CodeGenHLSL/builtins/abs.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/abs.hlsl
@@ -7,8 +7,7 @@
 
 
 // CHECK: define noundef signext i16 @
-// FIXME: int16_t is promoted to i32 now. Change to abs.i16 once it is fixed.
-// CHECK: call i32 @llvm.abs.i32(
+// CHECK: call i16 @llvm.abs.i16(
 int16_t test_abs_int16_t ( int16_t p0 ) {
   return abs ( p0 );
 }
diff --git a/clang/test/CodeGenHLSL/int16_t_add.hlsl b/clang/test/CodeGenHLSL/int16_t_add.hlsl
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenHLSL/int16_t_add.hlsl
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -D__HLSL_ENABLE_16_BIT \
+// RUN:   -emit-llvm -disable-llvm-passes -O3 -o - | FileCheck %s
+
+// Make sure generate i16 add.
+// CHECK: add nsw i16 %
+int16_t add(int16_t a, int16_t b) {
+  return a + b;
+}
+// CHECK: define noundef <2 x i16> @
+// CHECK: add <2 x i16>
+int16_t2 add(int16_t2 a, int16_t2 b) {
+  return a + b;
+}
+// CHECK: define noundef <3 x i16> @
+// CHECK: add <3 x i16>
+int16_t3 add(int16_t3 a, int16_t3 b) {
+  return a + b;
+}
+// CHECK: define noundef <4 x i16> @
+// CHECK: add <4 x i16>
+int16_t4 add(int16_t4 a, int16_t4 b) {
+  return a + b;
+}
diff --git a/clang/test/SemaHLSL/BitInt128.hlsl b/clang/test/SemaHLSL/BitInt128.hlsl
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaHLSL/BitInt128.hlsl
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -x hlsl -ast-dump -o - %s -verify
+
+// expected-error@+1 {{_BitInt is not supported on this target}}
+_BitInt(128) i128;
+
+// expected-error@+1 {{_BitInt is not supported on this target}}
+unsigned _BitInt(128) u128;