[Clang][LoongArch] Fix wrong return value type of __iocsrrd_h (llvm#84100)

relate:
https://gcc.gnu.org/pipermail/gcc-patches/2024-February/645016.html
(cherry picked from commit 2f479b8)

Author: wangleiat

clang/lib/Headers/larchintrin.h

@@ -156,7 +156,7 @@ extern __inline unsigned char
   return (unsigned char)__builtin_loongarch_iocsrrd_b((unsigned int)_1);
 }
 
-extern __inline unsigned char
+extern __inline unsigned short
     __attribute__((__gnu_inline__, __always_inline__, __artificial__))
     __iocsrrd_h(unsigned int _1) {
   return (unsigned short)__builtin_loongarch_iocsrrd_h((unsigned int)_1);

clang/test/CodeGen/LoongArch/intrinsic-la32.c

@@ -215,11 +215,11 @@ void cacop_w(unsigned long int a) {
 // LA32-LABEL: @iocsrrd_h_result(
 // LA32-NEXT:  entry:
 // LA32-NEXT:    [[TMP0:%.*]] = tail call i32 @llvm.loongarch.iocsrrd.h(i32 [[A:%.*]])
+// LA32-NEXT:    [[CONV_I:%.*]] = trunc i32 [[TMP0]] to i16
 // LA32-NEXT:    [[TMP1:%.*]] = tail call i32 @llvm.loongarch.iocsrrd.h(i32 [[A]])
-// LA32-NEXT:    [[CONV2:%.*]] = and i32 [[TMP0]], 255
-// LA32-NEXT:    [[ADD:%.*]] = add i32 [[TMP1]], [[CONV2]]
-// LA32-NEXT:    [[CONV4:%.*]] = trunc i32 [[ADD]] to i16
-// LA32-NEXT:    ret i16 [[CONV4]]
+// LA32-NEXT:    [[TMP2:%.*]] = trunc i32 [[TMP1]] to i16
+// LA32-NEXT:    [[CONV3:%.*]] = add i16 [[TMP2]], [[CONV_I]]
+// LA32-NEXT:    ret i16 [[CONV3]]
 //
 unsigned short iocsrrd_h_result(unsigned int a) {
   unsigned short b = __iocsrrd_h(a);

clang/test/CodeGen/LoongArch/intrinsic-la64.c

@@ -431,11 +431,11 @@ void loongarch_movgr2fcsr(int a) {
 // CHECK-LABEL: @iocsrrd_h_result(
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[TMP0:%.*]] = tail call i32 @llvm.loongarch.iocsrrd.h(i32 [[A:%.*]])
+// CHECK-NEXT:    [[CONV_I:%.*]] = trunc i32 [[TMP0]] to i16
 // CHECK-NEXT:    [[TMP1:%.*]] = tail call i32 @llvm.loongarch.iocsrrd.h(i32 [[A]])
-// CHECK-NEXT:    [[CONV2:%.*]] = and i32 [[TMP0]], 255
-// CHECK-NEXT:    [[ADD:%.*]] = add i32 [[TMP1]], [[CONV2]]
-// CHECK-NEXT:    [[CONV4:%.*]] = trunc i32 [[ADD]] to i16
-// CHECK-NEXT:    ret i16 [[CONV4]]
+// CHECK-NEXT:    [[TMP2:%.*]] = trunc i32 [[TMP1]] to i16
+// CHECK-NEXT:    [[CONV3:%.*]] = add i16 [[TMP2]], [[CONV_I]]
+// CHECK-NEXT:    ret i16 [[CONV3]]
 //
 unsigned short iocsrrd_h_result(unsigned int a) {
   unsigned short b = __iocsrrd_h(a);