[llvm] [SPIR-V] Upd SPV_KHR_shader_clock extension (PR #160147)

[Nikita Kornev via llvm-commits]

https://github.com/KornevNikita created https://github.com/llvm/llvm-project/pull/160147

Add __spirv_ReadClockKHR support

>From 151a17d645815759e371cdc581b2a2ecdbbdbce4 Mon Sep 17 00:00:00 2001
From: "Kornev, Nikita" <nikita.kornev at intel.com>
Date: Mon, 22 Sep 2025 18:28:27 +0200
Subject: [PATCH] [SPIR-V] Upd SPV_KHR_shader_clock extension

Add __spirv_ReadClockKHR support
---
 llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp       | 31 ++++++++++++-------
 llvm/lib/Target/SPIRV/SPIRVBuiltins.td        |  1 +
 .../SPV_KHR_shader_clock/shader_clock.ll      |  9 ++++++
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp b/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
index 2abd9d36f7606..8bedd8c860ab2 100644
--- a/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
@@ -1443,18 +1443,25 @@ static bool generateKernelClockInst(const SPIRV::IncomingCall *Call,
 
   Register ResultReg = Call->ReturnRegister;
 
-  // Deduce the `Scope` operand from the builtin function name.
-  SPIRV::Scope::Scope ScopeArg =
-      StringSwitch<SPIRV::Scope::Scope>(Builtin->Name)
-          .EndsWith("device", SPIRV::Scope::Scope::Device)
-          .EndsWith("work_group", SPIRV::Scope::Scope::Workgroup)
-          .EndsWith("sub_group", SPIRV::Scope::Scope::Subgroup);
-  Register ScopeReg = buildConstantIntReg32(ScopeArg, MIRBuilder, GR);
-
-  MIRBuilder.buildInstr(SPIRV::OpReadClockKHR)
-      .addDef(ResultReg)
-      .addUse(GR->getSPIRVTypeID(Call->ReturnType))
-      .addUse(ScopeReg);
+  if (Builtin->Name == "__spirv_ReadClockKHR") {
+    MIRBuilder.buildInstr(SPIRV::OpReadClockKHR)
+        .addDef(ResultReg)
+        .addUse(GR->getSPIRVTypeID(Call->ReturnType))
+        .addUse(Call->Arguments[0]);
+  } else {
+    // Deduce the `Scope` operand from the builtin function name.
+    SPIRV::Scope::Scope ScopeArg =
+        StringSwitch<SPIRV::Scope::Scope>(Builtin->Name)
+            .EndsWith("device", SPIRV::Scope::Scope::Device)
+            .EndsWith("work_group", SPIRV::Scope::Scope::Workgroup)
+            .EndsWith("sub_group", SPIRV::Scope::Scope::Subgroup);
+    Register ScopeReg = buildConstantIntReg32(ScopeArg, MIRBuilder, GR);
+
+    MIRBuilder.buildInstr(SPIRV::OpReadClockKHR)
+        .addDef(ResultReg)
+        .addUse(GR->getSPIRVTypeID(Call->ReturnType))
+        .addUse(ScopeReg);
+  }
 
   return true;
 }
diff --git a/llvm/lib/Target/SPIRV/SPIRVBuiltins.td b/llvm/lib/Target/SPIRV/SPIRVBuiltins.td
index d08560bb6565a..02f15bed396a1 100644
--- a/llvm/lib/Target/SPIRV/SPIRVBuiltins.td
+++ b/llvm/lib/Target/SPIRV/SPIRVBuiltins.td
@@ -1145,6 +1145,7 @@ defm : DemangledNativeBuiltin<"clock_read_sub_group", OpenCL_std, KernelClock, 0
 defm : DemangledNativeBuiltin<"clock_read_hilo_device", OpenCL_std, KernelClock, 0, 0, OpReadClockKHR>;
 defm : DemangledNativeBuiltin<"clock_read_hilo_work_group", OpenCL_std, KernelClock, 0, 0, OpReadClockKHR>;
 defm : DemangledNativeBuiltin<"clock_read_hilo_sub_group", OpenCL_std, KernelClock, 0, 0, OpReadClockKHR>;
+defm : DemangledNativeBuiltin<"__spirv_ReadClockKHR", OpenCL_std, KernelClock, 1, 1, OpReadClockKHR>;
 
 //===----------------------------------------------------------------------===//
 // Class defining an atomic instruction on floating-point numbers.
diff --git a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_shader_clock/shader_clock.ll b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_shader_clock/shader_clock.ll
index bd07ba1316ece..eb4cf76c96da6 100644
--- a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_shader_clock/shader_clock.ll
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_shader_clock/shader_clock.ll
@@ -20,6 +20,9 @@
 ; CHECK: OpReadClockKHR [[v2uint]] [[uint_1]]
 ; CHECK: OpReadClockKHR [[v2uint]] [[uint_2]]
 ; CHECK: OpReadClockKHR [[v2uint]] [[uint_3]]
+; CHECK: OpReadClockKHR [[ulong]] [[uint_1]]
+; CHECK: OpReadClockKHR [[ulong]] [[uint_2]]
+; CHECK: OpReadClockKHR [[ulong]] [[uint_3]]
 
 define dso_local spir_kernel void @test_clocks(ptr addrspace(1) nocapture noundef writeonly align 8 %out64, ptr addrspace(1) nocapture noundef writeonly align 8 %outv2) {
 entry:
@@ -39,6 +42,9 @@ entry:
   %call9 = tail call spir_func <2 x i32> @_Z25clock_read_hilo_sub_groupv()
   %arrayidx10 = getelementptr inbounds i8, ptr addrspace(1) %outv2, i32 16
   store <2 x i32> %call9, ptr addrspace(1) %arrayidx10, align 8
+  %call10 = call spir_func i64 @_Z27__spirv_ReadClockKHR_Rulongi(i32 1)
+  %call11 = call spir_func i64 @_Z27__spirv_ReadClockKHR_Rulongi(i32 2)
+  %call12 = call spir_func i64 @_Z27__spirv_ReadClockKHR_Rulongi(i32 3)
   ret void
 }
 
@@ -59,3 +65,6 @@ declare spir_func <2 x i32> @_Z26clock_read_hilo_work_groupv() local_unnamed_add
 
 ; Function Attrs: convergent nounwind
 declare spir_func <2 x i32> @_Z25clock_read_hilo_sub_groupv() local_unnamed_addr
+
+; Function Attrs: nounwind
+declare spir_func i64 @_Z27__spirv_ReadClockKHR_Rulongi(i32)