[clang] [llvm] [AMDGPU] Add amdgcn builtin for s_prefetch_inst (PR #211642)
Gang Chen via cfe-commits
cfe-commits at lists.llvm.org
Fri Jul 24 11:46:08 PDT 2026
https://github.com/cmc-rep updated https://github.com/llvm/llvm-project/pull/211642
>From 0d2306444c20272a9a4766f62e497cb408184b2b Mon Sep 17 00:00:00 2001
From: Gang Chen <Gang.Chen at amd.com>
Date: Mon, 22 Jun 2026 08:26:14 -0700
Subject: [PATCH 1/2] [AMDGPU] Add amdgcn builtin for s_prefetch_inst
---
clang/include/clang/Basic/BuiltinsAMDGPU.td | 1 +
clang/lib/CIR/CodeGen/CIRGenBuiltinAMDGPU.cpp | 6 ++
clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp | 3 +
.../CodeGenHIP/builtins-amdgcn-prefetch.hip | 71 +++++++++++++++++++
.../CodeGenOpenCL/builtins-amdgcn-gfx12.cl | 26 +++++++
5 files changed, 107 insertions(+)
create mode 100644 clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
diff --git a/clang/include/clang/Basic/BuiltinsAMDGPU.td b/clang/include/clang/Basic/BuiltinsAMDGPU.td
index a9d83d905a6ca..35d56abf9d3d5 100644
--- a/clang/include/clang/Basic/BuiltinsAMDGPU.td
+++ b/clang/include/clang/Basic/BuiltinsAMDGPU.td
@@ -762,6 +762,7 @@ def __builtin_amdgcn_s_barrier_leave : AMDGPUBuiltin<"void(_Constant short)", []
def __builtin_amdgcn_s_get_barrier_state : AMDGPUBuiltin<"unsigned int(int)", [], "gfx12-insts">;
def __builtin_amdgcn_s_get_named_barrier_state : AMDGPUBuiltin<"unsigned int(void *)", [], "gfx12-insts">;
def __builtin_amdgcn_s_prefetch_data : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "gfx12-insts">;
+def __builtin_amdgcn_s_prefetch_inst : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "gfx12-insts">;
def __builtin_amdgcn_s_buffer_prefetch_data : AMDGPUBuiltin<"void(__amdgpu_buffer_rsrc_t, _Constant int, unsigned int)", [Const], "gfx12-insts">;
def __builtin_amdgcn_global_load_tr_b64_v2i32 : AMDGPUBuiltin<"_ExtVector<2, int>(_ExtVector<2, int> address_space<1> *)", [Const], "gfx12-insts,wavefrontsize32">;
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinAMDGPU.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinAMDGPU.cpp
index 63bc9d8b6b144..b9ae5948ba013 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinAMDGPU.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinAMDGPU.cpp
@@ -1004,6 +1004,12 @@ CIRGenFunction::emitAMDGPUBuiltinExpr(unsigned builtinId,
getContext().BuiltinInfo.getName(builtinId));
return mlir::Value{};
}
+ case AMDGPU::BI__builtin_amdgcn_s_prefetch_inst: {
+ cgm.errorNYI(expr->getSourceRange(),
+ std::string("unimplemented AMDGPU builtin call: ") +
+ getContext().BuiltinInfo.getName(builtinId));
+ return mlir::Value{};
+ }
case Builtin::BIlogbf:
case Builtin::BI__builtin_logbf:
return emitLogbBuiltin(*this, expr, llvm::APFloat::IEEEsingle());
diff --git a/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp b/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
index 66e4e688e33ee..72d6f536165c5 100644
--- a/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
@@ -2197,6 +2197,9 @@ Value *CodeGenFunction::EmitAMDGPUBuiltinExpr(unsigned BuiltinID,
case AMDGPU::BI__builtin_amdgcn_s_prefetch_data:
return emitBuiltinWithOneOverloadedType<2>(
*this, E, Intrinsic::amdgcn_s_prefetch_data);
+ case AMDGPU::BI__builtin_amdgcn_s_prefetch_inst:
+ return emitBuiltinWithOneOverloadedType<2>(
+ *this, E, Intrinsic::amdgcn_s_prefetch_inst);
case Builtin::BIlogbf:
case Builtin::BI__builtin_logbf: {
Value *Src0 = EmitScalarExpr(E->getArg(0));
diff --git a/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip b/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
new file mode 100644
index 0000000000000..4be0262b2e0ce
--- /dev/null
+++ b/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
@@ -0,0 +1,71 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -target-cpu gfx1200 -emit-llvm -fcuda-is-device -o - %s | FileCheck %s --check-prefix=CHECK-GFX1200
+
+#define __device__ __attribute__((device))
+#define __shared__ __attribute__((shared))
+#define __constant__ __attribute__((constant))
+
+extern "C" __device__ int bar(const char *s);
+
+// CHECK-GFX1200-LABEL: define dso_local noundef i32 @_Z4foo1v(
+// CHECK-GFX1200-SAME: ) #[[ATTR0:[0-9]+]] {
+// CHECK-GFX1200-NEXT: [[ENTRY:.*:]]
+// CHECK-GFX1200-NEXT: [[S:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-GFX1200-NEXT: [[S_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[S]] to ptr
+// CHECK-GFX1200-NEXT: call void @llvm.amdgcn.s.prefetch.inst.p0(ptr @bar, i32 0)
+// CHECK-GFX1200-NEXT: store ptr addrspacecast (ptr addrspace(4) @.str to ptr), ptr [[S_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[TMP0:%.*]] = load ptr, ptr [[S_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[CALL:%.*]] = call i32 @bar(ptr noundef [[TMP0]]) #[[ATTR3:[0-9]+]]
+// CHECK-GFX1200-NEXT: ret i32 [[CALL]]
+//
+__device__ int foo1() {
+ __builtin_amdgcn_s_prefetch_inst((const void *)bar, 0);
+ const char *s = "hello world";
+ return bar(s);
+}
+
+// CHECK-GFX1200-LABEL: define dso_local noundef i32 @_Z4foo2i(
+// CHECK-GFX1200-SAME: i32 noundef [[ID:%.*]]) #[[ATTR0]] {
+// CHECK-GFX1200-NEXT: [[ENTRY:.*:]]
+// CHECK-GFX1200-NEXT: [[RETVAL:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-GFX1200-NEXT: [[ID_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-GFX1200-NEXT: [[S:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-GFX1200-NEXT: [[S2:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-GFX1200-NEXT: [[ID_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[ID_ADDR]] to ptr
+// CHECK-GFX1200-NEXT: [[S_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[S]] to ptr
+// CHECK-GFX1200-NEXT: [[S2_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[S2]] to ptr
+// CHECK-GFX1200-NEXT: store i32 [[ID]], ptr [[ID_ADDR_ASCAST]], align 4
+// CHECK-GFX1200-NEXT: call void @llvm.amdgcn.s.prefetch.inst.p0(ptr blockaddress(@_Z4foo2i, %[[NOBAR:.*]]), i32 0)
+// CHECK-GFX1200-NEXT: [[TMP0:%.*]] = load i32, ptr [[ID_ADDR_ASCAST]], align 4
+// CHECK-GFX1200-NEXT: [[CMP:%.*]] = icmp eq i32 [[TMP0]], 0
+// CHECK-GFX1200-NEXT: br i1 [[CMP]], label %[[IF_THEN:.*]], label %[[IF_END:.*]]
+// CHECK-GFX1200: [[IF_THEN]]:
+// CHECK-GFX1200-NEXT: store ptr addrspacecast (ptr addrspace(4) @.str to ptr), ptr [[S_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[TMP1:%.*]] = load ptr, ptr [[S_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[CALL:%.*]] = call i32 @bar(ptr noundef [[TMP1]]) #[[ATTR3]]
+// CHECK-GFX1200-NEXT: store i32 [[CALL]], ptr addrspace(5) [[RETVAL]], align 4
+// CHECK-GFX1200-NEXT: br label %[[RETURN:.*]]
+// CHECK-GFX1200: [[IF_END]]:
+// CHECK-GFX1200-NEXT: br label %[[NOBAR]]
+// CHECK-GFX1200: [[NOBAR]]:
+// CHECK-GFX1200-NEXT: store ptr addrspacecast (ptr addrspace(4) @.str.1 to ptr), ptr [[S2_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[TMP2:%.*]] = load ptr, ptr [[S2_ASCAST]], align 8
+// CHECK-GFX1200-NEXT: [[CALL1:%.*]] = call i32 @bar(ptr noundef [[TMP2]]) #[[ATTR3]]
+// CHECK-GFX1200-NEXT: store i32 [[CALL1]], ptr addrspace(5) [[RETVAL]], align 4
+// CHECK-GFX1200-NEXT: br label %[[RETURN]]
+// CHECK-GFX1200: [[RETURN]]:
+// CHECK-GFX1200-NEXT: [[TMP3:%.*]] = load i32, ptr addrspace(5) [[RETVAL]], align 4
+// CHECK-GFX1200-NEXT: ret i32 [[TMP3]]
+// CHECK-GFX1200: [[INDIRECTGOTO:.*:]]
+// CHECK-GFX1200-NEXT: indirectbr ptr poison, [label %[[NOBAR]]]
+//
+__device__ int foo2(int id) {
+ __builtin_amdgcn_s_prefetch_inst(&&NOBAR, 0);
+ if (id == 0) {
+ const char *s = "hello world";
+ return bar(s);
+ }
+NOBAR:
+ const char *s2 = "skip hello";
+ return bar(s2);
+}
diff --git a/clang/test/CodeGenOpenCL/builtins-amdgcn-gfx12.cl b/clang/test/CodeGenOpenCL/builtins-amdgcn-gfx12.cl
index 332a2fa94ee92..ffd1b152d9ef9 100644
--- a/clang/test/CodeGenOpenCL/builtins-amdgcn-gfx12.cl
+++ b/clang/test/CodeGenOpenCL/builtins-amdgcn-gfx12.cl
@@ -247,6 +247,32 @@ void test_s_prefetch_data(int *fp, global float *gp, constant char *cp, unsigned
__builtin_amdgcn_s_prefetch_data(cp, 31);
}
+// CHECK-LABEL: @test_s_prefetch_inst(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[FP_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT: [[GP_ADDR:%.*]] = alloca ptr addrspace(1), align 8, addrspace(5)
+// CHECK-NEXT: [[CP_ADDR:%.*]] = alloca ptr addrspace(4), align 8, addrspace(5)
+// CHECK-NEXT: [[LEN_ADDR:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT: store ptr [[FP:%.*]], ptr addrspace(5) [[FP_ADDR]], align 8
+// CHECK-NEXT: store ptr addrspace(1) [[GP:%.*]], ptr addrspace(5) [[GP_ADDR]], align 8
+// CHECK-NEXT: store ptr addrspace(4) [[CP:%.*]], ptr addrspace(5) [[CP_ADDR]], align 8
+// CHECK-NEXT: store i32 [[LEN:%.*]], ptr addrspace(5) [[LEN_ADDR]], align 4
+// CHECK-NEXT: [[TMP0:%.*]] = load ptr, ptr addrspace(5) [[FP_ADDR]], align 8
+// CHECK-NEXT: call void @llvm.amdgcn.s.prefetch.inst.p0(ptr [[TMP0]], i32 0)
+// CHECK-NEXT: [[TMP1:%.*]] = load ptr addrspace(1), ptr addrspace(5) [[GP_ADDR]], align 8
+// CHECK-NEXT: [[TMP2:%.*]] = load i32, ptr addrspace(5) [[LEN_ADDR]], align 4
+// CHECK-NEXT: call void @llvm.amdgcn.s.prefetch.inst.p1(ptr addrspace(1) [[TMP1]], i32 [[TMP2]])
+// CHECK-NEXT: [[TMP3:%.*]] = load ptr addrspace(4), ptr addrspace(5) [[CP_ADDR]], align 8
+// CHECK-NEXT: call void @llvm.amdgcn.s.prefetch.inst.p4(ptr addrspace(4) [[TMP3]], i32 31)
+// CHECK-NEXT: ret void
+//
+void test_s_prefetch_inst(int *fp, global float *gp, constant char *cp, unsigned int len)
+{
+ __builtin_amdgcn_s_prefetch_inst(fp, 0);
+ __builtin_amdgcn_s_prefetch_inst(gp, len);
+ __builtin_amdgcn_s_prefetch_inst(cp, 31);
+}
+
// CHECK-LABEL: @test_s_buffer_prefetch_data(
// CHECK-NEXT: entry:
// CHECK-NEXT: [[RSRC_ADDR:%.*]] = alloca ptr addrspace(8), align 16, addrspace(5)
>From b62cf4aae108294e6b9ef2f71ed277f55f00f23f Mon Sep 17 00:00:00 2001
From: "Chen, Gang" <gang.chen at amd.com>
Date: Fri, 24 Jul 2026 11:45:13 -0700
Subject: [PATCH 2/2] [AMDGPU] Address the review comments
---
clang/include/clang/Basic/BuiltinsAMDGPU.td | 9 ++++++---
.../include/clang/Basic/BuiltinsAMDGPUDocs.td | 20 +++++++++++++++++++
.../builtins-amdgcn-s-prefetch-inst-nyi.hip | 10 ++++++++++
.../CodeGenHIP/builtins-amdgcn-prefetch.hip | 2 +-
llvm/lib/TargetParser/AMDGPUTargetParser.cpp | 1 +
5 files changed, 38 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CIR/CodeGenHIP/builtins-amdgcn-s-prefetch-inst-nyi.hip
diff --git a/clang/include/clang/Basic/BuiltinsAMDGPU.td b/clang/include/clang/Basic/BuiltinsAMDGPU.td
index 35d56abf9d3d5..73b27a2b5c5cd 100644
--- a/clang/include/clang/Basic/BuiltinsAMDGPU.td
+++ b/clang/include/clang/Basic/BuiltinsAMDGPU.td
@@ -761,9 +761,12 @@ def __builtin_amdgcn_s_barrier_join : AMDGPUBuiltin<"void(void *)", [], "gfx12-i
def __builtin_amdgcn_s_barrier_leave : AMDGPUBuiltin<"void(_Constant short)", [], "gfx12-insts">;
def __builtin_amdgcn_s_get_barrier_state : AMDGPUBuiltin<"unsigned int(int)", [], "gfx12-insts">;
def __builtin_amdgcn_s_get_named_barrier_state : AMDGPUBuiltin<"unsigned int(void *)", [], "gfx12-insts">;
-def __builtin_amdgcn_s_prefetch_data : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "gfx12-insts">;
-def __builtin_amdgcn_s_prefetch_inst : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "gfx12-insts">;
-def __builtin_amdgcn_s_buffer_prefetch_data : AMDGPUBuiltin<"void(__amdgpu_buffer_rsrc_t, _Constant int, unsigned int)", [Const], "gfx12-insts">;
+def __builtin_amdgcn_s_prefetch_data : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "smem-prefetch-insts">;
+def __builtin_amdgcn_s_prefetch_inst : AMDGPUBuiltin<"void(void const *, unsigned int)", [Const], "smem-prefetch-insts"> {
+ let Documentation = [DocPrefetchInst_GFX12];
+ let ArgNames = ["ptr", "len"];
+}
+def __builtin_amdgcn_s_buffer_prefetch_data : AMDGPUBuiltin<"void(__amdgpu_buffer_rsrc_t, _Constant int, unsigned int)", [Const], "smem-prefetch-insts">;
def __builtin_amdgcn_global_load_tr_b64_v2i32 : AMDGPUBuiltin<"_ExtVector<2, int>(_ExtVector<2, int> address_space<1> *)", [Const], "gfx12-insts,wavefrontsize32">;
def __builtin_amdgcn_global_load_tr_b128_v8i16 : AMDGPUBuiltin<"_ExtVector<8, short>(_ExtVector<8, short> address_space<1> *)", [Const], "gfx12-insts,wavefrontsize32">;
diff --git a/clang/include/clang/Basic/BuiltinsAMDGPUDocs.td b/clang/include/clang/Basic/BuiltinsAMDGPUDocs.td
index 88b709471bd44..9aed40de73094 100644
--- a/clang/include/clang/Basic/BuiltinsAMDGPUDocs.td
+++ b/clang/include/clang/Basic/BuiltinsAMDGPUDocs.td
@@ -78,6 +78,13 @@ between standard floating-point types, integer types and packed low-precision fo
}];
}
+def DocCatAMDGPUPrefetch : DocumentationCategory<"Prefetch Builtins"> {
+ let Content = [{
+These builtins provide access to AMDGPU prefetch instructions, including instructions
+for prefetching data and instructions.
+}];
+}
+
//===----------------------------------------------------------------------===//
// ABI / Special Register Builtins — Documentation records
//===----------------------------------------------------------------------===//
@@ -793,3 +800,16 @@ using the scale factor ``scale``, then converts the values to a packed
integers.
}];
}
+
+//===----------------------------------------------------------------------===//
+// Prefetch Builtins
+//===----------------------------------------------------------------------===//
+
+def DocPrefetchInst_GFX12 : Documentation {
+ let Category = DocCatAMDGPUPrefetch;
+ let Content = [{
+Prefetch instructions into I-Cache from the address given by ``ptr`` pointing
+to instruction memory, with the length specified by ``len``, which should be
+0-31 (1-32 chunks, units of 128 bytes).
+}];
+}
\ No newline at end of file
diff --git a/clang/test/CIR/CodeGenHIP/builtins-amdgcn-s-prefetch-inst-nyi.hip b/clang/test/CIR/CodeGenHIP/builtins-amdgcn-s-prefetch-inst-nyi.hip
new file mode 100644
index 0000000000000..b5536464e25e3
--- /dev/null
+++ b/clang/test/CIR/CodeGenHIP/builtins-amdgcn-s-prefetch-inst-nyi.hip
@@ -0,0 +1,10 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -x hip -std=c++11 -fclangir \
+// RUN: -target-cpu gfx1250 -fcuda-is-device -emit-cir %s -verify -o %t.cir
+
+#define __device__ __attribute__((device))
+
+// expected-error at +2 {{ClangIR code gen Not Yet Implemented: unimplemented AMDGPU builtin call: __builtin_amdgcn_s_prefetch_inst}}
+__device__ void test_s_prefetch_inst(const void *p, unsigned int len) {
+ __builtin_amdgcn_s_prefetch_inst(p, len);
+}
diff --git a/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip b/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
index 4be0262b2e0ce..c4baa4ea195b3 100644
--- a/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
+++ b/clang/test/CodeGenHIP/builtins-amdgcn-prefetch.hip
@@ -1,5 +1,5 @@
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
-// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -target-cpu gfx1200 -emit-llvm -fcuda-is-device -o - %s | FileCheck %s --check-prefix=CHECK-GFX1200
+// RUN: %clang_cc1 -triple amdgpu12.00-amd-amdhsa -emit-llvm -fcuda-is-device -o - %s | FileCheck %s --check-prefix=CHECK-GFX1200
#define __device__ __attribute__((device))
#define __shared__ __attribute__((shared))
diff --git a/llvm/lib/TargetParser/AMDGPUTargetParser.cpp b/llvm/lib/TargetParser/AMDGPUTargetParser.cpp
index 23d67cd95696a..ea8faefa52937 100644
--- a/llvm/lib/TargetParser/AMDGPUTargetParser.cpp
+++ b/llvm/lib/TargetParser/AMDGPUTargetParser.cpp
@@ -639,6 +639,7 @@ static void fillAMDGCNFeatureMap(StringRef GPU, const Triple &T,
Features["wmma-128b-insts"] = true;
Features["swmmac-gfx1200-insts"] = true;
Features["atomic-fmin-fmax-global-f32"] = true;
+ Features["smem-prefetch-insts"] = true;
break;
case GK_GFX1170:
case GK_GFX1171:
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