[X86] Fix uninitialized variable warnings in cetintrin.h reported by #55224

[pengfei]

Summary

Fix uninitialized variables introduced by D116325.

[RKSimon]

clang/test/CodeGen/X86/sse-builtins-constrained.c

5 ↗

(On Diff #426968)

Any reason you can't commit this separately and immediately?

[pengfei]

clang/test/CodeGen/X86/sse-builtins-constrained.c

5 ↗

(On Diff #426968)

Good point! I'll do it.

[pengfei]

Seperated unrelated change and rebase.

[RKSimon]

LGTM - I'm intending to add -Wsystem-headers to the clang x86 builtins tests once everything is clean.

[pengfei]

In D124916#3490868, @RKSimon wrote:

LGTM - I'm intending to add -Wsystem-headers to the clang x86 builtins tests once everything is clean.

Thanks @RKSimon! That sounds great! I was thinking the headers will do diagnosis when -Wall.

[craig.topper]

clang/lib/Headers/cetintrin.h

45–47

The argument should also be (void).

58–60

Same here

[craig.topper]

clang/lib/Headers/cetintrin.h

48

So if CET isn't enabled this intrinsic returns a random value instead of 0 like _get_ssp?

[pengfei]

clang/lib/Headers/cetintrin.h

45–47

Thanks! Done by rGaa25b55bde87.

48

Exactly! These intrinsics are used to reflect the exact instructions behavior, i.e., a nop operation. They are used for performance.

clang/lib/Headers/cetintrin.h

 /*===---- cetintrin.h - CET intrinsic --------------------------------------===
  *
  * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  * See https://llvm.org/LICENSE.txt for license information.
  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  *
  *===-----------------------------------------------------------------------===
  */
static __inline__ void __DEFAULT_FN_ATTRS _inc_ssp(unsigned int __a) {
   __builtin_ia32_incsspd((int)__a);
 }
 #endif /* __x86_64__ */
 
 static __inline__ unsigned int __DEFAULT_FN_ATTRS _rdsspd(unsigned int __a) {
   return __builtin_ia32_rdsspd(__a);
 }
 
 static __inline__ unsigned int __DEFAULT_FN_ATTRS _rdsspd_i32() {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wuninitialized"
   unsigned int t;
   return __builtin_ia32_rdsspd(t);
+#pragma clang diagnostic pop
 }
 
 #ifdef __x86_64__
 static __inline__ unsigned long long __DEFAULT_FN_ATTRS _rdsspq(unsigned long long __a) {
   return __builtin_ia32_rdsspq(__a);
 }
 
 static __inline__ unsigned long long __DEFAULT_FN_ATTRS _rdsspq_i64() {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wuninitialized"
   unsigned long long t;
   return __builtin_ia32_rdsspq(t);
+#pragma clang diagnostic pop
 }
 #endif /* __x86_64__ */
 
 #ifdef __x86_64__
 static __inline__ unsigned long long __DEFAULT_FN_ATTRS _get_ssp(void) {
   return __builtin_ia32_rdsspq(0);
 }
 #else /* __x86_64__ */