[llvm] [SPIR-V] Ensure that OpExtInst instructions generated by NonSemantic_Shader_DebugInfo_100 are not mixed up with other OpExtInst instructions (PR #107007)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-spir-v

Author: Vyacheslav Levytskyy (VyacheslavLevytskyy)

<details>
<summary>Changes</summary>

This PR is to ensure that OpExtInst instructions generated by NonSemantic_Shader_DebugInfo_100 are not mixed up with other OpExtInst instructions.

Original implementation (https://github.com/llvm/llvm-project/pull/97558) has introduced an issue by moving OpExtInst instruction with the 3rd operand equal to DebugSource (value 35) or DebugCompilationUnit (value 1) even if OpExtInst is not generated by NonSemantic_Shader_DebugInfo_100 implementation code.

The reproducer is attached as a new test case. The code of the test case reproduces the issue, because "lgamma" has the same code (35) inside OpenCL_std as DebugSource inside NonSemantic_Shader_DebugInfo_100.

---
Full diff: https://github.com/llvm/llvm-project/pull/107007.diff


2 Files Affected:

- (modified) llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp (+4-1) 
- (added) llvm/test/CodeGen/SPIRV/debug-info/no-misplaced-opextinst.ll (+36) 


``````````diff
diff --git a/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp b/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
index a2fcfc636e3684..df42b6de193bda 100644
--- a/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp
@@ -428,7 +428,10 @@ void SPIRVModuleAnalysis::processOtherInstrs(const Module &M) {
         const unsigned OpCode = MI.getOpcode();
         if (OpCode == SPIRV::OpString) {
           collectOtherInstr(MI, MAI, SPIRV::MB_DebugStrings, IS);
-        } else if (OpCode == SPIRV::OpExtInst) {
+        } else if (OpCode == SPIRV::OpExtInst && MI.getOperand(2).isImm() &&
+                   MI.getOperand(2).getImm() ==
+                       SPIRV::InstructionSet::
+                           NonSemantic_Shader_DebugInfo_100) {
           MachineOperand Ins = MI.getOperand(3);
           namespace NS = SPIRV::NonSemanticExtInst;
           static constexpr int64_t GlobalNonSemanticDITy[] = {
diff --git a/llvm/test/CodeGen/SPIRV/debug-info/no-misplaced-opextinst.ll b/llvm/test/CodeGen/SPIRV/debug-info/no-misplaced-opextinst.ll
new file mode 100644
index 00000000000000..b3d202505d1226
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/debug-info/no-misplaced-opextinst.ll
@@ -0,0 +1,36 @@
+; This test is to ensure that OpExtInst generated by NonSemantic_Shader_DebugInfo_100
+; are not mixed up with other OpExtInst instructions.
+; The code of the test is a reproducer, because "lgamma" has the same code (35)
+; inside OpenCL_std as DebugSource inside NonSemantic_Shader_DebugInfo_100.
+
+; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; CHECK: %[[#Ocl:]] = OpExtInstImport "OpenCL.std"
+; CHECK: OpName %[[#Fun:]] "__devicelib_lgammaf"
+; CHECK: %[[#Fun]] = OpFunction %[[#]] None %[[#]]
+; CHECK: OpFunctionParameter
+; CHECK: %[[#]] = OpExtInst %[[#]] %[[#Ocl]] lgamma %[[#]]
+
+define weak_odr dso_local spir_kernel void @foo() {
+entry:
+  %r = tail call spir_func noundef float @lgammaf(float noundef 0x7FF8000000000000)
+  ret void
+}
+
+define weak dso_local spir_func float @lgammaf(float noundef %x) {
+entry:
+  %call = tail call spir_func float @__devicelib_lgammaf(float noundef %x)
+  ret float %call
+}
+
+define weak dso_local spir_func float @__devicelib_lgammaf(float noundef %x) {
+entry:
+  %call = tail call spir_func noundef float @_Z18__spirv_ocl_lgammaf(float noundef %x)
+  ret float %call
+}
+
+declare dso_local spir_func noundef float @_Z18__spirv_ocl_lgammaf(float noundef)

``````````

</details>


https://github.com/llvm/llvm-project/pull/107007