Re-add pattern for removing dead interface bindings. (#12560)

Re-adds the pattern for removing dead `hal.interface.binding.subspan` ops where the only users are `memref.assume_alignment` ops that no longer applies after making it a pure op.

compiler/src/iree/compiler/Codegen/Common/test/remove_dead_allocs.mlir

diff --git a/compiler/src/iree/compiler/Codegen/Common/test/remove_dead_allocs.mlir b/compiler/src/iree/compiler/Codegen/Common/test/remove_dead_allocs.mlir
index 146d3d0..50040b1 100644
--- a/compiler/src/iree/compiler/Codegen/Common/test/remove_dead_allocs.mlir
+++ b/compiler/src/iree/compiler/Codegen/Common/test/remove_dead_allocs.mlir
@@ -16,3 +16,13 @@
 // CHECK-LABEL: func.func @alloc_keep
 //  CHECK-NEXT:   %[[ALLOC:.+]] = memref.alloc
 //  CHECK-NEXT:   return %[[ALLOC]]
+
+// -----
+
+func.func @cleanup_only_assume_alignment_uses() {
+  %0 = hal.interface.binding.subspan set(0) binding(0) type(storage_buffer) : memref<42xf32>
+  memref.assume_alignment %0, 64 : memref<42xf32>
+  return
+}
+// CHECK-LABEL: func.func @cleanup_only_assume_alignment_uses()
+//  CHECK-NEXT:   return

compiler/src/iree/compiler/Codegen/Transforms/Transforms.cpp

diff --git a/compiler/src/iree/compiler/Codegen/Transforms/Transforms.cpp b/compiler/src/iree/compiler/Codegen/Transforms/Transforms.cpp
index 213bdc5..f8a1221 100644
--- a/compiler/src/iree/compiler/Codegen/Transforms/Transforms.cpp
+++ b/compiler/src/iree/compiler/Codegen/Transforms/Transforms.cpp
@@ -337,6 +337,26 @@
 //===--------------------------------------------------------------------====//
 
 namespace {
+
+// Erases the operation if its only users are memref.assume_alignment ops.
+static LogicalResult eraseAlignmentOnlyDeadOp(PatternRewriter &rewriter,
+                                              Operation *op) {
+  SmallVector<Operation *> deadUsers;
+  for (OpOperand &use : op->getUses()) {
+    if (auto user = dyn_cast<memref::AssumeAlignmentOp>(use.getOwner())) {
+      deadUsers.push_back(user);
+      continue;
+    }
+    // For any other use, return failure;
+    return failure();
+  }
+  for (auto user : deadUsers) {
+    rewriter.eraseOp(user);
+  }
+  rewriter.eraseOp(op);
+  return success();
+}
+
 // Removes operations with Allocate MemoryEffects but no uses.
 struct RemoveDeadMemAllocs : RewritePattern {
   RemoveDeadMemAllocs(MLIRContext *context, PatternBenefit benefit = 1)
@@ -348,26 +368,27 @@
     if (!memEffect || !memEffect.hasEffect<MemoryEffects::Allocate>()) {
       return failure();
     }
-    SmallVector<Operation *> deadUsers;
-    for (OpOperand &use : op->getUses()) {
-      if (auto user = dyn_cast<memref::AssumeAlignmentOp>(use.getOwner())) {
-        deadUsers.push_back(user);
-        continue;
-      }
-      // For any other use, return failure;
-      return failure();
-    }
-    for (auto user : deadUsers) {
-      rewriter.eraseOp(user);
-    }
-    rewriter.eraseOp(op);
-    return success();
+    return eraseAlignmentOnlyDeadOp(rewriter, op);
+  }
+};
+
+// Removes hal.interface.binding.subspan ops with only assume_alignment uses.
+struct RemoveDeadInterfaceBindings
+    : OpRewritePattern<IREE::HAL::InterfaceBindingSubspanOp> {
+  RemoveDeadInterfaceBindings(MLIRContext *context, PatternBenefit benefit = 1)
+      : OpRewritePattern<IREE::HAL::InterfaceBindingSubspanOp>(context,
+                                                               benefit) {}
+
+  LogicalResult matchAndRewrite(IREE::HAL::InterfaceBindingSubspanOp op,
+                                PatternRewriter &rewriter) const override {
+    return eraseAlignmentOnlyDeadOp(rewriter, op);
   }
 };
 }  // namespace
 
 void populateRemoveDeadMemAllocPatterns(RewritePatternSet &patterns) {
   patterns.insert<RemoveDeadMemAllocs>(patterns.getContext());
+  patterns.insert<RemoveDeadInterfaceBindings>(patterns.getContext());
 }
 
 }  // namespace iree_compiler