[CIR] Add back LoopOpInterface verification (#1635)

This commit essentially is a revert of
656151f. It appears that the underlying
issues are resolved.

Closes #425 and #927

Author: fangyi-zhou

clang/lib/CIR/Interfaces/CIRLoopOpInterface.cpp

@@ -44,11 +44,10 @@ void LoopOpInterface::getLoopOpSuccessorRegions(
 
 /// Verify invariants of the LoopOpInterface.
 llvm::LogicalResult detail::verifyLoopOpInterface(mlir::Operation *op) {
-  // FIXME: fix this so the conditionop isn't requiring MLIRCIR
-  // auto loopOp = mlir::cast<LoopOpInterface>(op);
-  // if (!mlir::isa<ConditionOp>(loopOp.getCond().back().getTerminator()))
-  //   return op->emitOpError(
-  //       "expected condition region to terminate with 'cir.condition'");
+  auto loopOp = mlir::cast<LoopOpInterface>(op);
+  if (!mlir::isa<ConditionOp>(loopOp.getCond().back().getTerminator()))
+    return op->emitOpError(
+        "expected condition region to terminate with 'cir.condition'");
   return llvm::success();
 }
 

clang/test/CIR/IR/invalid.cir

@@ -1532,3 +1532,44 @@ cir.global external dsolocal @vfp = #cir.ptr<null> : !cir.ptr<!cir.func<(!s32i)
 
 // expected-error @below {{integer or floating point type}}
 !complex = !cir.complex<!cir.ptr<!cir.void>>
+
+// -----
+
+#false = #cir.bool<false> : !cir.bool
+#true = #cir.bool<true> : !cir.bool
+cir.func @b0() {
+  cir.scope {
+    cir.while {  // expected-error {{expected condition region to terminate with 'cir.condition'}}
+      cir.yield
+    } do {
+      cir.br ^bb1
+    ^bb1:
+      cir.return
+    }
+  }
+  cir.return
+}
+
+// -----
+
+cir.func @invalid_cond_region_terminator(%arg0 : !cir.bool) -> !cir.void {
+  cir.do { // expected-error {{op expected condition region to terminate with 'cir.condition'}}
+    cir.yield
+  } while {
+    cir.yield
+  }
+  cir.return
+}
+
+// -----
+
+cir.func @invalidConditionTerminator (%arg0 : !cir.bool) -> !cir.void {
+  cir.for : cond { // expected-error {{op expected condition region to terminate with 'cir.condition'}}
+    cir.yield
+  } body {
+    cir.yield
+  } step {
+    cir.yield
+  }
+  cir.return
+}