diff --git a/llvm/test/Transforms/Util/flattencfg.ll b/llvm/test/Transforms/Util/flattencfg.ll
--- a/llvm/test/Transforms/Util/flattencfg.ll
+++ b/llvm/test/Transforms/Util/flattencfg.ll
@@ -1,11 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
 ; RUN: opt -passes=flattencfg -S < %s | FileCheck %s
 
 
 ; This test checks whether the pass completes without a crash.
 ; The code is not transformed in any way
-;
-; CHECK-LABEL: @test_not_crash
 define void @test_not_crash(i32 %in_a) #0 {
+; CHECK-LABEL: define void @test_not_crash
+; CHECK-SAME: (i32 [[IN_A:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP0:%.*]] = icmp eq i32 [[IN_A]], -1
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ne i32 [[IN_A]], 0
+; CHECK-NEXT:    [[COND0:%.*]] = and i1 [[CMP0]], [[CMP1]]
+; CHECK-NEXT:    br i1 [[COND0]], label [[B0:%.*]], label [[B1:%.*]]
+; CHECK:       b0:
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[IN_A]], 0
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp ne i32 [[IN_A]], 1
+; CHECK-NEXT:    [[COND1:%.*]] = or i1 [[CMP2]], [[CMP3]]
+; CHECK-NEXT:    br i1 [[COND1]], label [[EXIT:%.*]], label [[B1]]
+; CHECK:       b1:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
 entry:
   %cmp0 = icmp eq i32 %in_a, -1
   %cmp1 = icmp ne i32 %in_a, 0
@@ -25,17 +41,19 @@
   ret void
 }
 
-; CHECK-LABEL: @test_not_crash2
+define void @test_not_crash2(float %a, float %b) #0 {
+; CHECK-LABEL: define void @test_not_crash2
+; CHECK-SAME: (float [[A:%.*]], float [[B:%.*]]) {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    %0 = fcmp ult float %a
-; CHECK-NEXT:    %1 = fcmp ult float %b
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = and i1 %0, %1
-; CHECK-NEXT:    br i1 [[COND]], label %bb4, label %bb3
+; CHECK-NEXT:    [[TMP0:%.*]] = fcmp ult float [[A]], 1.000000e+00
+; CHECK-NEXT:    [[TMP1:%.*]] = fcmp ult float [[B]], 1.000000e+00
+; CHECK-NEXT:    [[TMP2:%.*]] = and i1 [[TMP0]], [[TMP1]]
+; CHECK-NEXT:    br i1 [[TMP2]], label [[BB4:%.*]], label [[BB3:%.*]]
 ; CHECK:       bb3:
-; CHECK-NEXT:    br label %bb4
+; CHECK-NEXT:    br label [[BB4]]
 ; CHECK:       bb4:
 ; CHECK-NEXT:    ret void
-define void @test_not_crash2(float %a, float %b) #0 {
+;
 entry:
   %0 = fcmp ult float %a, 1.000000e+00
   br i1 %0, label %bb0, label %bb1
@@ -54,18 +72,20 @@
   br i1 %1, label %bb4, label %bb3
 }
 
-; CHECK-LABEL: @test_not_crash3
+define void @test_not_crash3(i32 %a) #0 {
+; CHECK-LABEL: define void @test_not_crash3
+; CHECK-SAME: (i32 [[A:%.*]]) {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    %a_eq_0 = icmp eq i32 %a, 0
-; CHECK-NEXT:    %a_eq_1 = icmp eq i32 %a, 1
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = or i1 %a_eq_0, %a_eq_1
-; CHECK-NEXT:    br i1 [[COND]], label %bb2, label %bb3
+; CHECK-NEXT:    [[A_EQ_0:%.*]] = icmp eq i32 [[A]], 0
+; CHECK-NEXT:    [[A_EQ_1:%.*]] = icmp eq i32 [[A]], 1
+; CHECK-NEXT:    [[TMP0:%.*]] = or i1 [[A_EQ_0]], [[A_EQ_1]]
+; CHECK-NEXT:    br i1 [[TMP0]], label [[BB2:%.*]], label [[BB3:%.*]]
 ; CHECK:       bb2:
-; CHECK-NEXT:    br label %bb3
+; CHECK-NEXT:    br label [[BB3]]
 ; CHECK:       bb3:
-; CHECK-NEXT:    %check_badref = phi i32 [ 17, %entry ], [ 11, %bb2 ]
+; CHECK-NEXT:    [[CHECK_BADREF:%.*]] = phi i32 [ 17, [[ENTRY:%.*]] ], [ 11, [[BB2]] ]
 ; CHECK-NEXT:    ret void
-define void @test_not_crash3(i32 %a) #0 {
+;
 entry:
   %a_eq_0 = icmp eq i32 %a, 0
   br i1 %a_eq_0, label %bb0, label %bb1
@@ -88,18 +108,20 @@
 
 @g = global i32 0, align 4
 
-; CHECK-LABEL: @test_then
+define void @test_then(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: define void @test_then
+; CHECK-SAME: (i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[Z:%.*]]) {
 ; CHECK-NEXT:  entry.x:
-; CHECK-NEXT:    %cmp.x = icmp ne i32 %x, 0
-; CHECK-NEXT:    %cmp.y = icmp ne i32 %y, 0
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = or i1 %cmp.x, %cmp.y
-; CHECK-NEXT:    br i1 [[COND]], label %if.then.y, label %exit
+; CHECK-NEXT:    [[CMP_X:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT:    [[CMP_Y:%.*]] = icmp ne i32 [[Y]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = or i1 [[CMP_X]], [[CMP_Y]]
+; CHECK-NEXT:    br i1 [[TMP0]], label [[IF_THEN_Y:%.*]], label [[EXIT:%.*]]
 ; CHECK:       if.then.y:
-; CHECK-NEXT:    store i32 %z, ptr @g, align 4
-; CHECK-NEXT:    br label %exit
+; CHECK-NEXT:    store i32 [[Z]], ptr @g, align 4
+; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
-define void @test_then(i32 %x, i32 %y, i32 %z) {
+;
 entry.x:
   %cmp.x = icmp ne i32 %x, 0
   br i1 %cmp.x, label %if.then.x, label %entry.y
@@ -120,18 +142,20 @@
   ret void
 }
 
-; CHECK-LABEL: @test_else
+define void @test_else(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: define void @test_else
+; CHECK-SAME: (i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[Z:%.*]]) {
 ; CHECK-NEXT:  entry.x:
-; CHECK-NEXT:    %cmp.x = icmp eq i32 %x, 0
-; CHECK-NEXT:    %cmp.y = icmp eq i32 %y, 0
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = and i1 %cmp.x, %cmp.y
-; CHECK-NEXT:    br i1 [[COND]], label %exit, label %if.else.y
+; CHECK-NEXT:    [[CMP_X:%.*]] = icmp eq i32 [[X]], 0
+; CHECK-NEXT:    [[CMP_Y:%.*]] = icmp eq i32 [[Y]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = and i1 [[CMP_X]], [[CMP_Y]]
+; CHECK-NEXT:    br i1 [[TMP0]], label [[EXIT:%.*]], label [[IF_ELSE_Y:%.*]]
 ; CHECK:       if.else.y:
-; CHECK-NEXT:    store i32 %z, ptr @g, align 4
-; CHECK-NEXT:    br label %exit
+; CHECK-NEXT:    store i32 [[Z]], ptr @g, align 4
+; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
-define void @test_else(i32 %x, i32 %y, i32 %z) {
+;
 entry.x:
   %cmp.x = icmp eq i32 %x, 0
   br i1 %cmp.x, label %entry.y, label %if.else.x
@@ -152,18 +176,20 @@
   ret void
 }
 
-; CHECK-LABEL: @test_combine_and
+define void @test_combine_and(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: define void @test_combine_and
+; CHECK-SAME: (i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[Z:%.*]]) {
 ; CHECK-NEXT:  entry.x:
-; CHECK-NEXT:    %cmp.x = icmp eq i32 %x, 0
-; CHECK-NEXT:    %cmp.y = icmp eq i32 %y, 0
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = and i1 %cmp.x, %cmp.y
-; CHECK-NEXT:    br i1 [[COND]], label %exit, label %if.then.y
+; CHECK-NEXT:    [[CMP_X:%.*]] = icmp eq i32 [[X]], 0
+; CHECK-NEXT:    [[CMP_Y:%.*]] = icmp eq i32 [[Y]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = and i1 [[CMP_X]], [[CMP_Y]]
+; CHECK-NEXT:    br i1 [[TMP0]], label [[EXIT:%.*]], label [[IF_THEN_Y:%.*]]
 ; CHECK:       if.then.y:
-; CHECK-NEXT:    store i32 %z, ptr @g, align 4
-; CHECK-NEXT:    br label %exit
+; CHECK-NEXT:    store i32 [[Z]], ptr @g, align 4
+; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
-define void @test_combine_and(i32 %x, i32 %y, i32 %z) {
+;
 entry.x:
   %cmp.x = icmp eq i32 %x, 0
   br i1 %cmp.x, label %entry.y, label %if.else.x
@@ -184,18 +210,20 @@
   ret void
 }
 
-; CHECK-LABEL: @test_combine_or
+define void @test_combine_or(i32 %x, i32 %y, i32 %z) {
+; CHECK-LABEL: define void @test_combine_or
+; CHECK-SAME: (i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[Z:%.*]]) {
 ; CHECK-NEXT:  entry.x:
-; CHECK-NEXT:    %cmp.x = icmp ne i32 %x, 0
-; CHECK-NEXT:    %cmp.y = icmp ne i32 %y, 0
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = or i1 %cmp.x, %cmp.y
-; CHECK-NEXT:    br i1 [[COND]], label %if.else.y, label %exit
+; CHECK-NEXT:    [[CMP_X:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT:    [[CMP_Y:%.*]] = icmp ne i32 [[Y]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = or i1 [[CMP_X]], [[CMP_Y]]
+; CHECK-NEXT:    br i1 [[TMP0]], label [[IF_ELSE_Y:%.*]], label [[EXIT:%.*]]
 ; CHECK:       if.else.y:
-; CHECK-NEXT:    store i32 %z, ptr @g, align 4
-; CHECK-NEXT:    br label %exit
+; CHECK-NEXT:    store i32 [[Z]], ptr @g, align 4
+; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
-define void @test_combine_or(i32 %x, i32 %y, i32 %z) {
+;
 entry.x:
   %cmp.x = icmp ne i32 %x, 0
   br i1 %cmp.x, label %if.then.x, label %entry.y
@@ -216,12 +244,19 @@
   ret void
 }
 
-; This would crash.
-
 declare i1 @llvm.smax.i1(i1, i1) #0
 
-; CHECK-LABEL: @PR56875
 define void @PR56875(i1 %val_i1_5) {
+; CHECK-LABEL: define void @PR56875
+; CHECK-SAME: (i1 [[VAL_I1_5:%.*]]) {
+; CHECK-NEXT:  entry_1:
+; CHECK-NEXT:    ret void
+; CHECK:       bb_2:
+; CHECK-NEXT:    br label [[BB_4:%.*]]
+; CHECK:       bb_4:
+; CHECK-NEXT:    [[VAL_I1_46:%.*]] = call i1 @llvm.smax.i1(i1 [[VAL_I1_5]], i1 [[VAL_I1_5]])
+; CHECK-NEXT:    br i1 [[VAL_I1_46]], label [[BB_4]], label [[BB_2:%.*]]
+;
 entry_1:
   ret void
 
diff --git a/mlir/utils/emacs/mlir-mode.el b/mlir/utils/emacs/mlir-mode.el
--- a/mlir/utils/emacs/mlir-mode.el
+++ b/mlir/utils/emacs/mlir-mode.el
@@ -74,6 +74,11 @@
 ;;;###autoload
 (add-to-list 'auto-mode-alist (cons "\\.mlir\\'" 'mlir-mode))
 
+(defgroup mlir nil
+  "Major mode for editing MLIR source files."
+  :group 'languages
+  :prefix "mlir-")
+
 ;; Set default value of opt-tool to use as mlir-opt.
 (defcustom mlir-opt "mlir-opt"
   "Commandline MLIR opt tool to use."