Index: test/CodeGen/X86/tail-merge-after-mbp.ll
===================================================================
--- test/CodeGen/X86/tail-merge-after-mbp.ll
+++ test/CodeGen/X86/tail-merge-after-mbp.ll
@@ -1,94 +0,0 @@
-; RUN: llc -mtriple=x86_64-linux -o - %s | FileCheck %s
-
-%0 = type { %1, %3* }
-%1 = type { %2* }
-%2 = type { %2*, i8* }
-%3 = type { i32, i32 (i32, i32)* }
-
-
-declare i32 @Up(...) 
-declare i32 @f(i32, i32) 
-
-; check loop block_14 is not merged with block_21
-; check loop block_11 is not merged with block_18, block_25
-define i32 @foo(%0* nocapture readonly, i32, i1 %c, i8* %p1, %2** %p2) {
-; CHECK-LABEL: foo:
-; CHECK:     # %block_11
-; CHECK-NEXT:        movq    (%r14), %rax
-; CHECK-NEXT:        testq   %rax, %rax
-; CHECK-NEXT:        je      
-; CHECK-NEXT:# %block_14
-; CHECK-NEXT:        cmpq    $0, 8(%rax)
-; CHECK-NEXT:        jne    
-; CHECK-NEXT:# %block_18
-; CHECK-NEXT:        movq    (%r14), %rax
-; CHECK-NEXT:        testq   %rax, %rax
-; CHECK-NEXT:        je    
-; CHECK-NEXT:# %block_21
-; CHECK-NEXT:# =>This Inner Loop Header
-; CHECK-NEXT:        cmpq    $0, 8(%rax)
-; CHECK-NEXT:        jne  
-; CHECK-NEXT:# %block_25
-; CHECK-NEXT:#   in Loop
-; CHECK-NEXT:        movq    (%r14), %rax
-; CHECK-NEXT:        testq   %rax, %rax
-; CHECK-NEXT:        jne 
-  br i1 %c, label %block_34, label %block_3
-
-block_3:                                      ; preds = %2
-  br i1 %c, label %block_7, label %block_4
-
-block_4:                                      ; preds = %block_3
-  %a5 = tail call i32 @f(i32 undef, i32 undef)
-  %a6 = icmp eq i32 %a5, 0
-  br i1 %a6, label %block_7, label %block_34
-
-block_7:                                      ; preds = %block_4, %block_3
-  %a8 = icmp eq %2* null, null
-  br i1 %a8, label %block_34, label %block_9
-
-block_9:                                      ; preds = %block_7
-  %a10 = icmp eq i8* %p1, null
-  br i1 %a10, label %block_11, label %block_32
-
-block_11:                                     ; preds = %block_9
-  %a12 = load %2*, %2** %p2, align 8
-  %a13 = icmp eq %2* %a12, null
-  br i1 %a13, label %block_34, label %block_14
-
-block_14:                                     ; preds = %block_11
-  %a15 = getelementptr inbounds %2, %2* %a12, i64 0, i32 1
-  %a16 = load i8*, i8** %a15, align 8
-  %a17 = icmp eq i8* %a16, null
-  br i1 %a17, label %block_18, label %block_32
-
-block_18:                                     ; preds = %block_14
-  %a19 = load %2*, %2** %p2, align 8
-  %a20 = icmp eq %2* %a19, null
-  br i1 %a20, label %block_34, label %block_21
-
-block_21:                                     ; preds = %block_18
-  %a22 = getelementptr inbounds %2, %2* %a19, i64 0, i32 1
-  %a23 = load i8*, i8** %a22, align 8
-  %a24 = icmp eq i8* %a23, null
-  br i1 %a24, label %block_25, label %block_32
-
-block_25:                                     ; preds = %block_28, %block_21
-  %a26 = load %2*, %2** %p2, align 8
-  %a27 = icmp eq %2* %a26, null
-  br i1 %a27, label %block_34, label %block_28
-
-block_28:                                     ; preds = %block_25
-  %a29 = getelementptr inbounds %2, %2* %a26, i64 0, i32 1
-  %a30 = load i8*, i8** %a29, align 8
-  %a31 = icmp eq i8* %a30, null
-  br i1 %a31, label %block_25, label %block_32
-
-block_32:                                     ; preds = %block_28, %block_21, %block_14, %block_9
-  %a33 = tail call i32 (...) @Up()
-  br label %block_34
-
-block_34:                                     ; preds = %block_32, %block_25, %block_18, %block_11, %block_7, %block_4, %2
-  %a35 = phi i32 [ 0, %2 ], [ %a5, %block_4 ], [ 0, %block_7 ], [ 0, %block_11 ], [ 0, %block_32 ], [ 0, %block_18 ], [ 0, %block_25 ]
-  ret i32 %a35
-}
Index: test/CodeGen/X86/tail-merge-after-mbp.mir
===================================================================
--- test/CodeGen/X86/tail-merge-after-mbp.mir
+++ test/CodeGen/X86/tail-merge-after-mbp.mir
@@ -0,0 +1,249 @@
+# RUN: llc -mtriple=x86_64-linux -run-pass=block-placement -o - %s | FileCheck %s
+
+--- |
+  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64--linux"
+  
+  %0 = type { %1, %3* }
+  %1 = type { %2* }
+  %2 = type { %2*, i8* }
+  %3 = type { i32, i32 (i32, i32)* }
+  
+  declare i32 @Up(...)
+  
+  declare i32 @f(i32, i32)
+  
+  define i32 @foo(%0* nocapture readonly, i32, i1 %c, i8* %p1, %2** %p2) {
+    br i1 %c, label %block_34, label %block_3
+  
+  block_3:                                          ; preds = %2
+    br i1 %c, label %block_7, label %block_4
+  
+  block_4:                                          ; preds = %block_3
+    %a5 = tail call i32 @f(i32 undef, i32 undef)
+    %a6 = icmp eq i32 %a5, 0
+    br i1 %a6, label %block_7, label %block_34
+  
+  block_7:                                          ; preds = %block_4, %block_3
+    %a8 = icmp eq %2* null, null
+    br i1 %a8, label %block_34, label %block_9
+  
+  block_9:                                          ; preds = %block_7
+    %a10 = icmp eq i8* %p1, null
+    br i1 %a10, label %block_11, label %block_32
+  
+  block_11:                                         ; preds = %block_9
+    %a12 = load %2*, %2** %p2, align 8
+    %a13 = icmp eq %2* %a12, null
+    br i1 %a13, label %block_34, label %block_14
+  
+  block_14:                                         ; preds = %block_11
+    %a15 = getelementptr inbounds %2, %2* %a12, i64 0, i32 1
+    %a16 = load i8*, i8** %a15, align 8
+    %a17 = icmp eq i8* %a16, null
+    br i1 %a17, label %block_18, label %block_32
+  
+  block_18:                                         ; preds = %block_14
+    %a19 = load %2*, %2** %p2, align 8
+    %a20 = icmp eq %2* %a19, null
+    br i1 %a20, label %block_34, label %block_21
+  
+  block_21:                                         ; preds = %block_18
+    %a22 = getelementptr inbounds %2, %2* %a19, i64 0, i32 1
+    %a23 = load i8*, i8** %a22, align 8
+    %a24 = icmp eq i8* %a23, null
+    br i1 %a24, label %block_25.preheader, label %block_32
+  
+  block_25.preheader:                               ; preds = %block_21
+    br label %block_25
+  
+  block_25:                                         ; preds = %block_25.preheader, %block_28
+    %a26 = load %2*, %2** %p2, align 8
+    %a27 = icmp eq %2* %a26, null
+    br i1 %a27, label %block_34, label %block_28
+  
+  block_28:                                         ; preds = %block_25
+    %a29 = getelementptr inbounds %2, %2* %a26, i64 0, i32 1
+    %a30 = load i8*, i8** %a29, align 8
+    %a31 = icmp eq i8* %a30, null
+    br i1 %a31, label %block_25, label %block_32
+  
+  block_32:                                         ; preds = %block_28, %block_21, %block_14, %block_9
+    %a33 = tail call i32 (...) @Up()
+    br label %block_34
+  
+  block_34:                                         ; preds = %block_25, %block_32, %block_18, %block_11, %block_7, %block_4, %2
+    %a35 = phi i32 [ 0, %2 ], [ %a5, %block_4 ], [ 0, %block_7 ], [ 0, %block_11 ], [ 0, %block_32 ], [ 0, %block_18 ], [ 0, %block_25 ]
+    ret i32 %a35
+  }
+  
+  ; Function Attrs: nounwind
+  declare void @llvm.stackprotector(i8*, i8**) #0
+  
+  attributes #0 = { nounwind }
+
+...
+---
+# CHECK: name:            foo
+name:            foo
+alignment:       4
+tracksRegLiveness: true
+liveins:         
+  - { reg: '%edx' }
+  - { reg: '%rcx' }
+  - { reg: '%r8' }
+fixedStack:      
+  - { id: 0, type: spill-slot, offset: -32, size: 8, alignment: 16, callee-saved-register: '%rbx' }
+  - { id: 1, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '%r14' }
+  - { id: 2, type: spill-slot, offset: -16, size: 8, alignment: 16, callee-saved-register: '%rbp' }
+
+# check loop block_14 is not merged with block_21
+# check loop block_11 is not merged with block_18, block_25
+#
+# CHECK: bb.9.block_11:
+# CHECK: MOV64rm
+# CHECK-NEXT: TEST64rr
+# CHECK-NEXT: JE_1
+# CHECK: bb.10.block_14:
+# CHECK: CMP64mi8
+# CHECK-NEXT: JNE_1
+# CHECK: bb.11.block_18:
+# CHECK: MOV64rm
+# CHECK-NEXT: TEST64rr
+# CHECK-NEXT: JE_1
+# CHECK: bb.12.block_21:
+# CHECK: CMP64mi8
+# CHECK-NEXT: JNE_1
+# CHECK: bb.13.block_25:
+# CHECK: MOV64rm
+# CHECK-NEXT: TEST64rr
+# CHECK-NEXT: JNE_1
+
+body:             |
+  bb.0 (%ir-block.2):
+    successors: %bb.1(0x40000000), %bb.2.block_3(0x40000000)
+    liveins: %edx, %rcx, %r8, %rbp, %r14, %rbx
+  
+    frame-setup PUSH64r killed %rbp, implicit-def %rsp, implicit %rsp
+    frame-setup PUSH64r killed %r14, implicit-def %rsp, implicit %rsp
+    frame-setup PUSH64r killed %rbx, implicit-def %rsp, implicit %rsp
+    %r14 = MOV64rr %r8
+    %rbx = MOV64rr %rcx
+    TEST8ri %dl, 1, implicit-def %eflags, implicit killed %edx
+    JE_1 %bb.2.block_3, implicit %eflags
+  
+  bb.1:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    JMP_1 %bb.16.block_34
+  
+  bb.2.block_3:
+    successors: %bb.4.block_7(0x40000000), %bb.3.block_4(0x40000000)
+    liveins: %eflags, %rbx, %r14
+  
+    JNE_1 %bb.4.block_7, implicit %eflags
+  
+  bb.3.block_4:
+    successors: %bb.4.block_7(0x30000000), %bb.16.block_34(0x50000000)
+    liveins: %rbx, %r14
+  
+    CALL64pcrel32 @f, csr_64, implicit %rsp, implicit undef %edi, implicit undef %esi, implicit-def %rsp, implicit-def %eax
+    %ebp = MOV32rr %eax
+    TEST32rr %ebp, %ebp, implicit-def %eflags
+    JNE_1 %bb.16.block_34, implicit %eflags
+  
+  bb.4.block_7:
+    successors: %bb.5(0x30000000), %bb.6.block_9(0x50000000)
+    liveins: %rbx, %r14
+  
+    %al = MOV8ri 1
+    TEST8rr killed %al, %al, implicit-def %eflags
+    JE_1 %bb.6.block_9, implicit killed %eflags
+  
+  bb.5:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    JMP_1 %bb.16.block_34
+  
+  bb.6.block_9:
+    successors: %bb.7.block_11(0x30000000), %bb.15.block_32(0x50000000)
+    liveins: %rbx, %r14
+  
+    TEST64rr killed %rbx, %rbx, implicit-def %eflags
+    JNE_1 %bb.15.block_32, implicit %eflags
+  
+  bb.7.block_11:
+    successors: %bb.8(0x30000000), %bb.9.block_14(0x50000000)
+    liveins: %r14
+  
+    %rax = MOV64rm %r14, 1, _, 0, _
+    TEST64rr %rax, %rax, implicit-def %eflags
+    JNE_1 %bb.9.block_14, implicit killed %eflags
+  
+  bb.8:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    JMP_1 %bb.16.block_34
+  
+  bb.9.block_14:
+    successors: %bb.10.block_18(0x30000000), %bb.15.block_32(0x50000000)
+    liveins: %rax, %r14
+  
+    CMP64mi8 killed %rax, 1, _, 8, _, 0, implicit-def %eflags
+    JNE_1 %bb.15.block_32, implicit %eflags
+  
+  bb.10.block_18:
+    successors: %bb.11(0x30000000), %bb.12.block_21(0x50000000)
+    liveins: %r14
+  
+    %rax = MOV64rm %r14, 1, _, 0, _
+    TEST64rr %rax, %rax, implicit-def %eflags
+    JNE_1 %bb.12.block_21, implicit %eflags
+  
+  bb.11:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    JMP_1 %bb.16.block_34
+  
+  bb.12.block_21:
+    successors: %bb.13.block_25(0x71555555), %bb.15.block_32(0x0eaaaaab)
+    liveins: %r14, %rax
+  
+    CMP64mi8 killed %rax, 1, _, 8, _, 0, implicit-def %eflags
+    JNE_1 %bb.15.block_32, implicit %eflags
+  
+  bb.13.block_25:
+    successors: %bb.14(0x04000000), %bb.12.block_21(0x7c000000)
+    liveins: %r14
+  
+    %rax = MOV64rm %r14, 1, _, 0, _
+    TEST64rr %rax, %rax, implicit-def %eflags
+    JNE_1 %bb.12.block_21, implicit %eflags
+  
+  bb.14:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    JMP_1 %bb.16.block_34
+  
+  bb.15.block_32:
+    successors: %bb.16.block_34(0x80000000)
+  
+    %ebp = XOR32rr undef %ebp, undef %ebp, implicit-def dead %eflags
+    dead %eax = XOR32rr undef %eax, undef %eax, implicit-def dead %eflags, implicit-def %al
+    CALL64pcrel32 @Up, csr_64, implicit %rsp, implicit %al, implicit-def %rsp, implicit-def dead %eax
+  
+  bb.16.block_34:
+    liveins: %ebp
+  
+    %eax = MOV32rr killed %ebp
+    %rbx = POP64r implicit-def %rsp, implicit %rsp
+    %r14 = POP64r implicit-def %rsp, implicit %rsp
+    %rbp = POP64r implicit-def %rsp, implicit %rsp
+    RETQ %eax
+
+...