[X86] Add notes to a few intrinsics

This a change corresponding to the clang change in
https://reviews.llvm.org/D45616

Reviewers: craig.topper, uriel.k, RKSimon, andrew.w.kaylor, spatel, scanon, efriedma

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D48280

llvm-svn: 335340

llvm/include/llvm/IR/IntrinsicsX86.td

@@ -211,6 +211,8 @@ let TargetPrefix = "x86" in {  // All intrinsics start with "llvm.x86.".
   def int_x86_sse_cmp_ss : GCCBuiltin<"__builtin_ia32_cmpss">,
               Intrinsic<[llvm_v4f32_ty], [llvm_v4f32_ty,
                          llvm_v4f32_ty, llvm_i8_ty], [IntrNoMem]>;
+  // NOTE: This comparison intrinsic is not used by clang as long as the
+  //       distinction in signaling behaviour is not implemented.
   def int_x86_sse_cmp_ps :
               Intrinsic<[llvm_v4f32_ty], [llvm_v4f32_ty,
                          llvm_v4f32_ty, llvm_i8_ty], [IntrNoMem]>;
@@ -317,6 +319,8 @@ let TargetPrefix = "x86" in {  // All intrinsics start with "llvm.x86.".
   def int_x86_sse2_cmp_sd : GCCBuiltin<"__builtin_ia32_cmpsd">,
               Intrinsic<[llvm_v2f64_ty], [llvm_v2f64_ty,
                          llvm_v2f64_ty, llvm_i8_ty], [IntrNoMem]>;
+  // NOTE: This comparison intrinsic is not used by clang as long as the
+  //       distinction in signaling behaviour is not implemented.
   def int_x86_sse2_cmp_pd :
               Intrinsic<[llvm_v2f64_ty], [llvm_v2f64_ty,
                          llvm_v2f64_ty, llvm_i8_ty], [IntrNoMem]>;
@@ -5517,6 +5521,8 @@ let TargetPrefix = "x86" in {
 
 // Misc.
 let TargetPrefix = "x86" in {
+  // NOTE: These comparison intrinsics are not used by clang as long as the
+  //       distinction in signaling behaviour is not implemented.
   def int_x86_avx512_mask_cmp_ps_512 :
               Intrinsic<[llvm_v16i1_ty], [llvm_v16f32_ty, llvm_v16f32_ty,
                          llvm_i32_ty, llvm_i32_ty], [IntrNoMem]>;