[llvm] [SPIR-V] Change a way SPIR-V Backend API works with user facing options (PR #124745)

[Vyacheslav Levytskyy via llvm-commits]

================
@@ -150,9 +153,14 @@ void SPIRVSubtarget::initAvailableExtInstSets() {
     AvailableExtInstSets.insert(SPIRV::InstructionSet::OpenCL_std);
 
   // Handle extended instruction sets from extensions.
-  if (canUseExtension(
-          SPIRV::Extension::SPV_AMD_shader_trinary_minmax_extension)) {
-    AvailableExtInstSets.insert(
-        SPIRV::InstructionSet::SPV_AMD_shader_trinary_minmax);
-  }
+  accountForAMDShaderTrinaryMinmax();
+}
+
+// Set available extensions after SPIRVSubtarget is created.
+void SPIRVSubtarget::initAvailableExtensions(
+    std::set<SPIRV::Extension::Extension> AllowedExtIds) {
----------------
VyacheslavLevytskyy wrote:

Indeed, thank you. Changed.

https://github.com/llvm/llvm-project/pull/124745