[clang] ee92122 - [Win/X86] Make _m_prefetch[w] builtins to avoid winnt.h conflicts (#115099)
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Mon Feb 3 14:06:02 PST 2025
Author: Reid Kleckner
Date: 2025-02-03T14:05:58-08:00
New Revision: ee92122b53c7af26bb766e89e1d30ceb2fd5bb93
URL: https://github.com/llvm/llvm-project/commit/ee92122b53c7af26bb766e89e1d30ceb2fd5bb93
DIFF: https://github.com/llvm/llvm-project/commit/ee92122b53c7af26bb766e89e1d30ceb2fd5bb93.diff
LOG: [Win/X86] Make _m_prefetch[w] builtins to avoid winnt.h conflicts (#115099)
This is similar in spirit to previous changes to make _mm_mfence
builtins to avoid conflicts with winnt.h and other MSVC ecosystem
headers that pre-declare compiler intrinsics as extern "C" symbols.
Also update the feature flag for _mm_prefetch to sse, which is more accurate than mmx.
This should fix issue #87515.
Added:
Modified:
clang/include/clang/Basic/BuiltinsX86.td
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/Headers/prfchwintrin.h
clang/lib/Headers/xmmintrin.h
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/BuiltinsX86.td b/clang/include/clang/Basic/BuiltinsX86.td
index 572ac7235be02f..bb24069dff29b0 100644
--- a/clang/include/clang/Basic/BuiltinsX86.td
+++ b/clang/include/clang/Basic/BuiltinsX86.td
@@ -130,6 +130,10 @@ let Attributes = [Const, NoThrow, RequiredVectorWidth<128>] in {
}
}
+let Features = "sse", Header = "xmmintrin.h", Attributes = [NoThrow, Const] in {
+ def _mm_prefetch : X86LibBuiltin<"void(void const *, int)">;
+}
+
// AVX
let Attributes = [Const, NoThrow, RequiredVectorWidth<256>], Features = "avx" in {
foreach Op = ["addsub", "hadd", "hsub", "max", "min"] in {
@@ -138,6 +142,12 @@ let Attributes = [Const, NoThrow, RequiredVectorWidth<256>], Features = "avx" in
}
}
+// PRFCHW
+let Features = "prfchw", Header = "x86intrin.h", Attributes = [NoThrow, Const] in {
+ def _m_prefetch : X86LibBuiltin<"void(void *)">;
+ def _m_prefetchw : X86LibBuiltin<"void(void volatile const *)">;
+}
+
// Mechanically ported builtins from the original `.def` file.
//
@@ -146,10 +156,6 @@ let Attributes = [Const, NoThrow, RequiredVectorWidth<256>], Features = "avx" in
// current formulation is based on what was easiest to recognize from the
// pre-TableGen version.
-let Features = "mmx", Attributes = [NoThrow, Const] in {
- def _mm_prefetch : X86NoPrefixBuiltin<"void(char const *, int)">;
-}
-
let Features = "sse", Attributes = [NoThrow] in {
def ldmxcsr : X86Builtin<"void(unsigned int)">;
}
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 11fa295dad9524..4d3d9e9897c148 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -15374,6 +15374,17 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
Function *F = CGM.getIntrinsic(Intrinsic::prefetch, Address->getType());
return Builder.CreateCall(F, {Address, RW, Locality, Data});
}
+ case X86::BI_m_prefetch:
+ case X86::BI_m_prefetchw: {
+ Value *Address = Ops[0];
+ // The 'w' suffix implies write.
+ Value *RW =
+ ConstantInt::get(Int32Ty, BuiltinID == X86::BI_m_prefetchw ? 1 : 0);
+ Value *Locality = ConstantInt::get(Int32Ty, 0x3);
+ Value *Data = ConstantInt::get(Int32Ty, 1);
+ Function *F = CGM.getIntrinsic(Intrinsic::prefetch, Address->getType());
+ return Builder.CreateCall(F, {Address, RW, Locality, Data});
+ }
case X86::BI_mm_clflush: {
return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_sse2_clflush),
Ops[0]);
diff --git a/clang/lib/Headers/prfchwintrin.h b/clang/lib/Headers/prfchwintrin.h
index eaea5f3cf8febf..8ec55d7073716f 100644
--- a/clang/lib/Headers/prfchwintrin.h
+++ b/clang/lib/Headers/prfchwintrin.h
@@ -14,6 +14,10 @@
#ifndef __PRFCHWINTRIN_H
#define __PRFCHWINTRIN_H
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
/// Loads a memory sequence containing the specified memory address into
/// all data cache levels.
///
@@ -26,11 +30,7 @@
///
/// \param __P
/// A pointer specifying the memory address to be prefetched.
-static __inline__ void __attribute__((__always_inline__, __nodebug__))
-_m_prefetch(void *__P)
-{
- __builtin_prefetch (__P, 0, 3 /* _MM_HINT_T0 */);
-}
+void _m_prefetch(void *__P);
/// Loads a memory sequence containing the specified memory address into
/// the L1 data cache and sets the cache-coherency state to modified.
@@ -48,13 +48,10 @@ _m_prefetch(void *__P)
///
/// \param __P
/// A pointer specifying the memory address to be prefetched.
-static __inline__ void __attribute__((__always_inline__, __nodebug__))
-_m_prefetchw(volatile const void *__P)
-{
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wcast-qual"
- __builtin_prefetch ((const void*)__P, 1, 3 /* _MM_HINT_T0 */);
-#pragma clang diagnostic pop
-}
+void _m_prefetchw(volatile const void *__P);
+
+#if defined(__cplusplus)
+} // extern "C"
+#endif
#endif /* __PRFCHWINTRIN_H */
diff --git a/clang/lib/Headers/xmmintrin.h b/clang/lib/Headers/xmmintrin.h
index 20e66d190113a3..1fb070bca827e9 100644
--- a/clang/lib/Headers/xmmintrin.h
+++ b/clang/lib/Headers/xmmintrin.h
@@ -2197,10 +2197,7 @@ _mm_storer_ps(float *__p, __m128 __a)
#define _MM_HINT_T2 1
#define _MM_HINT_NTA 0
-#ifndef _MSC_VER
-/* FIXME: We have to #define this because "sel" must be a constant integer, and
- Sema doesn't do any form of constant propagation yet. */
-
+#if 0
/// Loads one cache line of data from the specified address to a location
/// closer to the processor.
///
@@ -2225,6 +2222,10 @@ _mm_storer_ps(float *__p, __m128 __a)
/// be generated. \n
/// _MM_HINT_T2: Move data using the T2 hint. The PREFETCHT2 instruction will
/// be generated.
+///
+/// _mm_prefetch is implemented as a "library builtin" directly in Clang,
+/// similar to how it is done in MSVC. Clang will warn if the user doesn't
+/// include xmmintrin.h or immintrin.h.
#define _mm_prefetch(a, sel) (__builtin_prefetch((const void *)(a), \
((sel) >> 2) & 1, (sel) & 0x3))
#endif
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