[Stream] Remove unused variables (i.e., dead code) and clean up tests. (#19964)

- Remove unused variables.
- Remove extra module op from lit tests.
- Switch all the tests to use iree_encoding.unspecialized_encoding
except the sizeof tests. The sizeof tests capture the actual layouts
from backend attributes. The other tests do not really care what
attributes are used.
- Move GPU sizeof tests to where CPU sizeof tests locate.

Signed-off-by: hanhanW <[email protected]>

Author: hanhanW

compiler/src/iree/compiler/Dialect/Stream/Transforms/SpecializeEncodings.cpp

@@ -150,9 +150,9 @@ updateBindingEncodings(FunctionOpInterface funcOp,
 /// this case, we have to duplicate the executable with updated encoding, and
 /// modify the dispatch to launch proper executable based on resolved encoding
 /// layouts.
-static LogicalResult duplicateExecutablesPerLayoutVariant(
-    ModuleOp moduleOp, SymbolTable symbolTable, FunctionOpInterface funcOp,
-    IREE::Stream::ResolveLayoutAttrFn resolveLayoutAttr) {
+static LogicalResult
+duplicateExecutablesPerLayoutVariant(ModuleOp moduleOp, SymbolTable symbolTable,
+                                     FunctionOpInterface funcOp) {
   MLIRContext *ctx = moduleOp.getContext();
   IRRewriter rewriter(ctx);
 
@@ -563,18 +563,13 @@ struct SpecializeEncodingsPass
       return signalPassFailure();
     }
 
-    SymbolTable symbolTable(moduleOp);
-    llvm::MapVector<StringRef, IREE::Stream::ExecutableOp> executableOps;
-    for (auto executableOp : moduleOp.getOps<IREE::Stream::ExecutableOp>()) {
-      executableOps[executableOp.getName()] = executableOp;
-    }
-
     IREE::Stream::AffinityAnalysis affinityAnalysis(moduleOp);
     if (failed(affinityAnalysis.run())) {
       moduleOp.emitError("failed on running affinity analysis");
       return signalPassFailure();
     }
 
+    SymbolTable symbolTable(moduleOp);
     IREE::Stream::ResolveLayoutAttrFn resolveLayoutAttr =
         usedDialects[0]->makeLayoutAttrResolver(moduleOp);
     for (auto funcOp : moduleOp.getOps<FunctionOpInterface>()) {
@@ -584,8 +579,8 @@ struct SpecializeEncodingsPass
             "failed on adding layouts to Stream::TensorPhaseOp with encodings");
         return signalPassFailure();
       }
-      if (failed(duplicateExecutablesPerLayoutVariant(
-              moduleOp, symbolTable, funcOp, resolveLayoutAttr))) {
+      if (failed(duplicateExecutablesPerLayoutVariant(moduleOp, symbolTable,
+                                                      funcOp))) {
         funcOp.emitError("failed on executable duplication");
         return signalPassFailure();
       }