[spirv] Fix gen_spirv_dialect.py and add spv.Unreachable

This CL fixed gen_spirv_dialect.py to support nested delimiters when
chunking existing ODS entries in .td files and to allow ops without
correspondence in the spec. This is needed to pull in the definition
of OpUnreachable.

PiperOrigin-RevId: 277486465

1 files changed, 20 insertions, 0 deletions

diff --git a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
index 8d32daadb6b..85e22a5c391 100644
--- a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
+++ b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
@@ -2286,6 +2286,26 @@ static void print(spirv::UndefOp undefOp, OpAsmPrinter &printer) {
 }
 
 //===----------------------------------------------------------------------===//
+// spv.Unreachable
+//===----------------------------------------------------------------------===//
+
+static LogicalResult verify(spirv::UnreachableOp unreachableOp) {
+  auto *op = unreachableOp.getOperation();
+  auto *block = op->getBlock();
+  // Fast track: if this is in entry block, its invalid. Otherwise, if no
+  // predecessors, it's valid.
+  if (block->isEntryBlock())
+    return unreachableOp.emitOpError("cannot be used in reachable block");
+  if (block->hasNoPredecessors())
+    return success();
+
+  // TODO(antiagainst): further verification needs to analyze reachablility from
+  // the entry block.
+
+  return success();
+}
+
+//===----------------------------------------------------------------------===//
 // spv.Variable
 //===----------------------------------------------------------------------===//