X86 Intrinsics: _bit_scan_forward should not be under #ifdef __RDRND__

[zvi]

Summary

The _bit_scan_forward and _bit_scan_reverse intrinsics were accidentally
masked under the preprocessor checks that prune intrinsics definitions for the
benefit of faster compile-time on Windows. This patch moves the
definitons out of that region.

Fixes pr33722

[craig.topper]

lib/Headers/immintrin.h

230

Looks like we now aren't removing rdrand64_step. Should we put the rdrand functions together and not have bit_scan between them?

[zvi]

lib/Headers/immintrin.h

230

Right! Thanks for pointing that out.

[zvi]

rdrand64_step should be under the ifdef

[craig.topper]

LGTM

lib/Headers/immintrin.h

_rdrand16_step(unsigned short *__p)
   return __builtin_ia32_rdrand16_step(__p);
 }
 
 static __inline__ int __attribute__((__always_inline__, __nodebug__, __target__("rdrnd")))
 _rdrand32_step(unsigned int *__p)
 {
   return __builtin_ia32_rdrand32_step(__p);
 }
+#endif /* __RDRND__ */
 
 /* __bit_scan_forward */
 static __inline__ int __attribute__((__always_inline__, __nodebug__))
 _bit_scan_forward(int __A) {
   return __builtin_ctz(__A);
 }
 
 /* __bit_scan_reverse */
 static __inline__ int __attribute__((__always_inline__, __nodebug__))
 _bit_scan_reverse(int __A) {
   return 31 - __builtin_clz(__A);
 }
 
 #ifdef __x86_64__
 static __inline__ int __attribute__((__always_inline__, __nodebug__, __target__("rdrnd")))
 _rdrand64_step(unsigned long long *__p)
 {
   return __builtin_ia32_rdrand64_step(__p);
 }
 #endif
-#endif /* __RDRND__ */
 
 #if !defined(_MSC_VER) || __has_feature(modules) || defined(__FSGSBASE__)
 #ifdef __x86_64__
 static __inline__ unsigned int __attribute__((__always_inline__, __nodebug__, __target__("fsgsbase")))
 _readfsbase_u32(void)
 {
   return __builtin_ia32_rdfsbase32();
 }

test/CodeGen/bitscan-builtins.c

 // RUN: %clang_cc1 -ffreestanding -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s
 
+// PR33722
+// RUN: %clang_cc1 -ffreestanding -triple x86_64-unknown-unknown -D_MSC_VER -emit-llvm -o - %s | FileCheck %s
+
 #include <immintrin.h>
 
 int test_bit_scan_forward(int a) {
   return _bit_scan_forward(a);
 // CHECK: @test_bit_scan_forward
 // CHECK: %[[call:.*]] = call i32 @llvm.cttz.i32(
 // CHECK: ret i32 %[[call]]
 }
 
 int test_bit_scan_reverse(int a) {
   return _bit_scan_reverse(a);
 // CHECK:  %[[call:.*]] = call i32 @llvm.ctlz.i32(
 // CHECK:  %[[sub:.*]] = sub nsw i32 31, %[[call]]
 // CHECK: ret i32 %[[sub]]
 }