[CIR] Add X86 prefetch builtins #168051
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[CIR] Add X86 prefetch builtins #168051
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-clangir Author: Hendrik Hübner (HendrikHuebner) ChangesUpstreams the sse2 prefetch builtin and adds two more builtins not present in the incubator repo ( Full diff: https://github.com/llvm/llvm-project/pull/168051.diff 5 Files Affected:
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 2124b1dc62a81..219846ec7a884 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4116,7 +4116,7 @@ def CIR_PrefetchOp : CIR_Op<"prefetch"> {
$locality is a temporal locality specifier ranging from (0) - no locality,
to (3) - extremely local, keep in cache. If $locality is not present, the
default value is 3.
-
+
$isWrite specifies whether the prefetch is for a 'read' or 'write'. If
$isWrite is not specified, it means that prefetch is prepared for 'read'.
}];
@@ -4150,7 +4150,7 @@ def CIR_ObjSizeOp : CIR_Op<"objsize", [Pure]> {
When the `min` attribute is present, the operation returns the minimum
guaranteed accessible size. When absent (max mode), it returns the maximum
possible object size. Corresponds to `llvm.objectsize`'s `min` argument.
-
+
The `dynamic` attribute determines if the value should be evaluated at
runtime. Corresponds to `llvm.objectsize`'s `dynamic` argument.
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
index 2d6cf30fa2ded..6f23f2be79e91 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
@@ -21,6 +21,11 @@
using namespace clang;
using namespace clang::CIRGen;
+/// Get integer from a mlir::Value that is an int constant or a constant op.
+static int64_t getIntValueFromConstOp(mlir::Value val) {
+ return val.getDefiningOp<cir::ConstantOp>().getIntValue().getSExtValue();
+}
+
template <typename... Operands>
static mlir::Value emitIntrinsicCallOp(CIRGenFunction &cgf, const CallExpr *e,
const std::string &str,
@@ -34,6 +39,28 @@ static mlir::Value emitIntrinsicCallOp(CIRGenFunction &cgf, const CallExpr *e,
.getResult();
}
+static mlir::Value emitPrefetch(CIRGenFunction &cgf, unsigned builtinID,
+ const CallExpr *e,
+ mlir::Value &addr, int64_t hint) {
+ CIRGenBuilderTy &builder = cgf.getBuilder();
+ mlir::Location location = cgf.getLoc(e->getExprLoc());
+ mlir::Type voidTy = builder.getVoidTy();
+ mlir::Value address = builder.createPtrBitcast(addr, voidTy);
+ bool isWrite{};
+ int locality{};
+
+ if (builtinID == X86::BI_mm_prefetch) {
+ isWrite = (hint >> 2) & 0x1;
+ locality = hint & 0x3;
+ } else {
+ isWrite = (builtinID == X86::BI_m_prefetchw);
+ locality = 0x3;
+ }
+
+ cir::PrefetchOp::create(builder, location, address, locality, isWrite);
+ return {};
+}
+
mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID,
const CallExpr *e) {
if (builtinID == Builtin::BI__builtin_cpu_is) {
@@ -87,6 +114,9 @@ mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID,
case X86::BI_mm_sfence:
return emitIntrinsicCallOp(*this, e, "x86.sse.sfence", voidTy);
case X86::BI_mm_prefetch:
+ case X86::BI_m_prefetch:
+ case X86::BI_m_prefetchw:
+ return emitPrefetch(*this, builtinID, e, ops[0], getIntValueFromConstOp(ops[1]));
case X86::BI__rdtsc:
case X86::BI__builtin_ia32_rdtscp:
case X86::BI__builtin_ia32_lzcnt_u16:
diff --git a/clang/test/CIR/CodeGen/X86/prefetchw-builtin.c b/clang/test/CIR/CodeGen/X86/prefetchw-builtin.c
new file mode 100644
index 0000000000000..fbf7894ba69b2
--- /dev/null
+++ b/clang/test/CIR/CodeGen/X86/prefetchw-builtin.c
@@ -0,0 +1,36 @@
+
+// RUN: %clang_cc1 -x c -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-cir -o %t.cir -Wall -Werror
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -x c -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-llvm -o %t.ll -Wall -Werror
+// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s
+
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fno-signed-char -fclangir -emit-cir -o %t.cir -Wall -Werror
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-llvm -o %t.ll -Wall -Werror
+// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s
+
+// RUN: %clang_cc1 -x c -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -emit-llvm -o - -Wall -Werror | FileCheck %s -check-prefix=OGCG
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -emit-llvm -o - -Wall -Werror | FileCheck %s -check-prefix=OGCG
+
+
+#include <x86intrin.h>
+
+void test_m_prefetch(void *p) {
+ // CIR-LABEL: test_m_prefetch
+ // LLVM-LABEL: test_m_prefetch
+ // OGCG-LABEL: test_m_prefetch
+ return _m_prefetch(p);
+ // CIR: cir.prefetch read locality(0) %{{.*}} : !cir.ptr<!void>
+ // LLVM: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+ // OGCG: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+}
+
+void test_m_prefetch_w(void *p) {
+ // CIR-LABEL: test_m_prefetch_w
+ // LLVM-LABEL: test_m_prefetch_w
+ // OGCG-LABEL: test_m_prefetch_w
+ return _m_prefetchw(p);
+ // CIR: cir.prefetch write locality(0) %{{.*}} : !cir.ptr<!void>
+ // LLVM: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+ // OGCG: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+}
diff --git a/clang/test/CIR/CodeGen/X86/sse-builtins.c b/clang/test/CIR/CodeGen/X86/sse-builtins.c
index 3a61018741958..07c586d7c0b8c 100644
--- a/clang/test/CIR/CodeGen/X86/sse-builtins.c
+++ b/clang/test/CIR/CodeGen/X86/sse-builtins.c
@@ -26,3 +26,21 @@ void test_mm_sfence(void) {
// LLVM: call void @llvm.x86.sse.sfence()
// OGCG: call void @llvm.x86.sse.sfence()
}
+
+void test_mm_prefetch(char const* p) {
+ // CIR-LABEL: test_mm_prefetch
+ // LLVM-LABEL: test_mm_prefetch
+ _mm_prefetch(p, 0);
+ // CIR: cir.prefetch read locality(0) %{{.*}} : !cir.ptr<!void>
+ // LLVM: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+ // OGCG: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
+}
+
+void test_mm_prefetch_local(char const* p) {
+ // CIR-LABEL: test_mm_prefetch_local
+ // LLVM-LABEL: test_mm_prefetch_local
+ _mm_prefetch(p, 3);
+ // CIR: cir.prefetch read locality(3) %{{.*}} : !cir.ptr<!void>
+ // LLVM: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 3, i32 1)
+ // OGCG: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 3, i32 1)
+}
diff --git a/clang/test/CIR/CodeGen/X86/sse2-builtins.c b/clang/test/CIR/CodeGen/X86/sse2-builtins.c
index 144ca143fbf15..3429eee093f6a 100644
--- a/clang/test/CIR/CodeGen/X86/sse2-builtins.c
+++ b/clang/test/CIR/CodeGen/X86/sse2-builtins.c
@@ -16,7 +16,6 @@
#include <immintrin.h>
-
void test_mm_clflush(void* A) {
// CIR-LABEL: test_mm_clflush
// LLVM-LABEL: test_mm_clflush
|
HendrikHuebner
commented
Nov 14, 2025
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✅ With the latest revision this PR passed the C/C++ code formatter. |
bcardosolopes
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andykaylor
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🐧 Linux x64 Test Results
|
| } | ||
|
|
||
| cir::PrefetchOp::create(builder, location, address, locality, isWrite); | ||
| return {}; |
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Why not emit a PoisonValue/UndefValue here? The result is not going to be used anyways and will be later eliminated. A comment explaining probably helps. I'm against using optional because mlir::Value type already incorporates that semantics and is a weird shortcut we'd be taking.
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I think its easier to just move the NYI error diagnostic to CIRGenBuiltinX86 and avoid this entire discussion.
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HendrikHuebner
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| llvm_unreachable("Bad evaluation kind in EmitBuiltinExpr"); | ||
| } | ||
|
|
||
| cgm.errorNYI(e->getSourceRange(), |
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This check is now handled in CIRGenBuiltinX86, so we can return empty values without triggering the NYI error
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I don't think that's right. That will only report the error for missing X86 builtins. This was a backstop for everything else.
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I caught missing builtins for other targets in emitTargetArchBuiltinExpr
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What about __builtin_constant_p? This was also handling missing builtins that are not target-specific?
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Upstreams the sse2 prefetch builtin and adds two more builtins not present in the incubator repo (
prefetchhandprefetchw)