https://github.com/dpaoliello created
https://github.com/llvm/llvm-project/pull/93235
#67174 added the `__prefetch` intrinsic, however it used the wrong signature:
the argument should be `const void*`, not `void*`.
Docs:
https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-170#:~:text=__prefetch
Unfortunately, this can't be backported (there are no more 18.x releases, and
this change is a breaking change), so I'll see if I can get a workaround added
on MSVC's side for Clang 18.
>From 97d449824f7ce9c2f1501e3f51468950c4114d13 Mon Sep 17 00:00:00 2001
From: Daniel Paoliello
Date: Thu, 23 May 2024 12:48:13 -0700
Subject: [PATCH] Fix signature for __prefetch
---
clang/include/clang/Basic/BuiltinsAArch64.def | 2 +-
clang/lib/Headers/intrin.h| 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/include/clang/Basic/BuiltinsAArch64.def
b/clang/include/clang/Basic/BuiltinsAArch64.def
index cf8711c6eaee3..5f53c98167dfb 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.def
+++ b/clang/include/clang/Basic/BuiltinsAArch64.def
@@ -290,7 +290,7 @@ TARGET_HEADER_BUILTIN(_CountLeadingZeros64, "UiULLi", "nh",
INTRIN_H, ALL_MS_LAN
TARGET_HEADER_BUILTIN(_CountOneBits, "UiUNi", "nh", INTRIN_H,
ALL_MS_LANGUAGES, "")
TARGET_HEADER_BUILTIN(_CountOneBits64, "UiULLi", "nh", INTRIN_H,
ALL_MS_LANGUAGES, "")
-TARGET_HEADER_BUILTIN(__prefetch, "vv*", "nh", INTRIN_H, ALL_MS_LANGUAGES, "")
+TARGET_HEADER_BUILTIN(__prefetch, "vvC*", "nh", INTRIN_H, ALL_MS_LANGUAGES, "")
#undef BUILTIN
#undef LANGBUILTIN
diff --git a/clang/lib/Headers/intrin.h b/clang/lib/Headers/intrin.h
index 7eb6dceaabfae..5ceb986a1f652 100644
--- a/clang/lib/Headers/intrin.h
+++ b/clang/lib/Headers/intrin.h
@@ -378,7 +378,7 @@ unsigned int _CountLeadingSigns64(__int64);
unsigned int _CountOneBits(unsigned long);
unsigned int _CountOneBits64(unsigned __int64);
-void __cdecl __prefetch(void *);
+void __cdecl __prefetch(const void *);
#endif
/**\
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