[libc] Fix 64-bit ARM support and header includes

[kristof.beyls]

libc/src/__support/FPUtil/PlatformDefs.h

18–19

Apologies for the drive-by comment.
I just noticed the spelling arch64. It looks like maybe this should be aarch64?

[sivachandra]

Thanks for catching the build problems with exhaustive tests. They have bit rotted a bit because we don't run them on any bot.

libc/src/__support/FPUtil/PlatformDefs.h

18–19

On aarch64, long doubles are not the 64-bit IEEE double precision numbers. So, this would be incorrect after the typo is fixed.

libc/test/src/math/exhaustive/cosf_test.cpp

12

You should not need these headers to be included at all.

[ddcc]

Sorry for the delay, Louis was helping me upstream this but now I can update it directly.

[ddcc]

Clarify long double is for apple arm 64-bit

[sivachandra]

In D114236#3277979, @ddcc wrote:

Clarify long double is for apple arm 64-bit

LGTM, but is there any document that can be added as a reference in a comment in PlatformDefs.h?

[ddcc]

Add apple reference

libc/src/__support/FPUtil/PlatformDefs.h

 #define LLVM_LIBC_SRC_SUPPORT_FPUTIL_PLATFORM_DEFS_H
 
 #include "src/__support/architectures.h"
 
 #if defined(LLVM_LIBC_ARCH_X86)
 #define X87_FPU
 #endif
 
-#if defined(_WIN32)
+// https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms
+#if defined(_WIN32) || (defined(__APPLE__) && defined(__aarch64__))
 #define LONG_DOUBLE_IS_DOUBLE
 #endif
 
 #if !defined(LONG_DOUBLE_IS_DOUBLE) && defined(X87_FPU)
 #define SPECIAL_X86_LONG_DOUBLE
 #endif
 
 #endif // LLVM_LIBC_SRC_SUPPORT_FPUTIL_PLATFORM_DEFS_H

libc/test/src/math/exhaustive/cosf_test.cpp

 //===-- Exhaustive test for cosf ------------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/TestHelpers.h"
 #include "src/math/cosf.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
 #include <math.h>
 
 using FPBits = __llvm_libc::fputil::FPBits<float>;
 
 namespace mpfr = __llvm_libc::testing::mpfr;
 
 TEST(LlvmLibccosffExhaustiveTest, AllValues) {
   uint32_t bits = 0;
   do {
     FPBits xbits(bits);
     float x = float(xbits);
     ASSERT_MPFR_MATCH(mpfr::Operation::Cos, x, __llvm_libc::cosf(x), 1.0);
   } while (bits++ < 0xffff'ffffU);
 }

libc/test/src/math/exhaustive/expm1f_test.cpp

 //===-- Exhaustive test for expm1f-----------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/TestHelpers.h"
 #include "src/math/expm1f.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
 #include <math.h>
 
 using FPBits = __llvm_libc::fputil::FPBits<float>;
 
 namespace mpfr = __llvm_libc::testing::mpfr;
 

libc/test/src/math/exhaustive/sinf_test.cpp

 //===-- Exhaustive test for sinf ------------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/TestHelpers.h"
 #include "src/math/sinf.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
 #include <math.h>
 
 using FPBits = __llvm_libc::fputil::FPBits<float>;
 
 namespace mpfr = __llvm_libc::testing::mpfr;
 
 TEST(LlvmLibcsinffExhaustiveTest, AllValues) {
   uint32_t bits = 0;
   do {
     FPBits xbits(bits);
     float x = float(xbits);
     ASSERT_MPFR_MATCH(mpfr::Operation::Sin, x, __llvm_libc::sinf(x), 1.0);
   } while (bits++ < 0xffff'ffffU);
 }

libc/test/src/math/exhaustive/sqrtf_test.cpp

 //===-- Exhaustive test for sqrtf -----------------------------------------===//
 //
 // 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
 //
 //===---------------------------------------------------------------------===//
 
 #include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/TestHelpers.h"
 #include "src/math/sqrtf.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
 #include <math.h>
 
 using FPBits = __llvm_libc::fputil::FPBits<float>;
 
 namespace mpfr = __llvm_libc::testing::mpfr;
 
 TEST(LlvmLibcSqrtfExhaustiveTest, AllValues) {
   uint32_t bits = 0;
   do {
     FPBits xbits(bits);
     float x = float(xbits);
     ASSERT_MPFR_MATCH(mpfr::Operation::Sqrt, x, __llvm_libc::sqrtf(x), 0.5);
   } while (bits++ < 0xffff'ffffU);
 }