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

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

Original implementation
(#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.

Author: VyacheslavLevytskyy

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[] = {

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)