[llvm] [AMDGPU][Uniformity][TTI] Make Uniformity Analysis Operand-Aware with Custom Target Hook (PR #137639)

[Pankaj Dwivedi via llvm-commits]

================
@@ -785,6 +797,14 @@ void GenericUniformityAnalysisImpl<ContextT>::markDivergent(
     const InstructionT &I) {
   if (isAlwaysUniform(I))
     return;
+  // Check if instruction requires custom uniformity analysis
+  auto It = UniformInstruction.find(&I);
+  if (It != UniformInstruction.end()) {
+    if (It->second == InstructionUniformity::Custom && isCustomUniform(I)) {
+      addUniformOverride(I);
----------------
PankajDwivedi-25 wrote:

may be i should skip marking these custom candidate uniform until divergence propagation is not done by simply skipping those candidates? add let later, another helper 'analyseCustomUniformCandidates` can mark them uniform?

https://github.com/llvm/llvm-project/pull/137639