[clang] [X86] Fix the implementation of __readcr[4, 8]/__writecr[4, 8] to work in 64-bit mode (PR #122238)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Phoebe Wang (phoebewang)

<details>
<summary>Changes</summary>

According to MSVC, __readcr4/__writecr4 return/use `unsigned __int64`, and are supported on both x86 and x64. While __readcr8/__writecr8 are only supported on x64. So we use __INTPTR_TYPE__ and __int64 respectively.

Following: https://github.com/llvm/llvm-project/commit/3cec2a17de744900401c83aedb442e2acc1f23f8

Ref.:
https://learn.microsoft.com/en-us/cpp/intrinsics/readcr3?view=msvc-170
https://learn.microsoft.com/en-us/cpp/intrinsics/readcr8?view=msvc-170

---
Full diff: https://github.com/llvm/llvm-project/pull/122238.diff


1 Files Affected:

- (modified) clang/lib/Headers/intrin.h (+4-4) 


``````````diff
diff --git a/clang/lib/Headers/intrin.h b/clang/lib/Headers/intrin.h
index e8a01d1888026c..376046aeeaf5e9 100644
--- a/clang/lib/Headers/intrin.h
+++ b/clang/lib/Headers/intrin.h
@@ -94,8 +94,8 @@ void __outwordstring(unsigned short, unsigned short *, unsigned long);
 unsigned long __readcr0(void);
 unsigned long __readcr2(void);
 unsigned __LPTRINT_TYPE__ __readcr3(void);
-unsigned long __readcr4(void);
-unsigned long __readcr8(void);
+unsigned __LPTRINT_TYPE__ __readcr4(void);
+unsigned __int64 __readcr8(void);
 unsigned int __readdr(unsigned int);
 #ifdef __i386__
 unsigned char __readfsbyte(unsigned long);
@@ -124,8 +124,8 @@ void __vmx_vmptrst(unsigned __int64 *);
 void __wbinvd(void);
 void __writecr0(unsigned int);
 void __writecr3(unsigned __INTPTR_TYPE__);
-void __writecr4(unsigned int);
-void __writecr8(unsigned int);
+void __writecr4(unsigned __INTPTR_TYPE__);
+void __writecr8(unsigned __int64);
 void __writedr(unsigned int, unsigned int);
 void __writefsbyte(unsigned long, unsigned char);
 void __writefsdword(unsigned long, unsigned long);

``````````

</details>


https://github.com/llvm/llvm-project/pull/122238