Index: llvm/trunk/lib/Target/ARM/ARMComputeBlockSize.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMComputeBlockSize.cpp
+++ llvm/trunk/lib/Target/ARM/ARMComputeBlockSize.cpp
@@ -35,6 +35,7 @@
     case ARM::tBcc:
     // optimizeThumb2JumpTables.
     case ARM::t2BR_JT:
+    case ARM::tBR_JTr:
       return true;
   }
   return false;
Index: llvm/trunk/test/CodeGen/Thumb/PR36658.mir
===================================================================
--- llvm/trunk/test/CodeGen/Thumb/PR36658.mir
+++ llvm/trunk/test/CodeGen/Thumb/PR36658.mir
@@ -0,0 +1,359 @@
+# REQUIRES: asserts
+# RUN: llc -run-pass arm-cp-islands %s -o - | FileCheck %s
+#
+# This is a reduced test made to expose a bug in
+# ARMConstantIslandPass in Thumb1 mode, see PR36658.
+
+# Verify optimized JT code uses TBB instructions.
+# CHECK-LABEL: bb.7.entry:
+# CHECK: tTBB_JT $pc, killed $r2, %jump-table.1, 0
+# CHECK-LABEL: bb.8:
+# CHECK: JUMPTABLE_TBB 0, %jump-table.1, 44
+
+# CHECK-LABEL: bb.11.entry:
+# CHECK: $r1 = tMOVSr $r0, implicit-def dead $cpsr
+# CHECK: tTBB_JT $pc, killed $r2, %jump-table.0, 1
+# CHECK-LABEL: bb.12:
+# CHECK: JUMPTABLE_TBB 1, %jump-table.0, 44
+
+--- |
+  ; ModuleID = 'PR36658.ll'
+  source_filename = "PR36658.ll"
+  target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+  target triple = "thumbv5e-none-linux-gnueabi"
+
+  declare i32 @foo1(...)
+
+  declare i32 @foo2(i32)
+
+  declare i32 @foo3(i32*)
+
+  ; Function Attrs: nounwind optsize
+  define internal fastcc i32 @foo4(i32* nocapture %ignore_ptr) #0 {
+  entry:
+    %call = tail call i32 @foo3(i32* undef)
+    switch i32 %call, label %sw.epilog [
+      i32 120, label %sw.bb
+      i32 48, label %sw.bb73
+      i32 49, label %sw.bb73
+      i32 50, label %sw.bb73
+      i32 51, label %sw.bb73
+      i32 52, label %sw.bb73
+      i32 53, label %sw.bb73
+      i32 54, label %sw.bb73
+      i32 55, label %sw.bb73
+      i32 92, label %cleanup
+      i32 39, label %cleanup
+      i32 34, label %cleanup
+      i32 10, label %sw.bb91
+      i32 110, label %sw.bb93
+      i32 116, label %sw.bb94
+      i32 114, label %sw.bb95
+      i32 102, label %sw.bb96
+      i32 98, label %sw.bb97
+      i32 97, label %sw.bb98
+      i32 118, label %sw.bb106
+      i32 101, label %sw.bb107
+      i32 69, label %sw.bb107
+      i32 63, label %cleanup
+    ]
+
+  sw.bb:                                            ; preds = %entry
+    br label %while.cond
+
+  while.cond:                                       ; preds = %while.cond, %sw.bb
+    %call5 = tail call i32 @foo3(i32* null)
+    br label %while.cond
+
+  sw.bb73:                                          ; preds = %entry, %entry, %entry, %entry, %entry, %entry, %entry, %entry
+    %0 = and i32 %call, -8
+    %1 = icmp eq i32 %0, 48
+    br i1 %1, label %while.body83.preheader, label %while.end88
+
+  while.body83.preheader:                           ; preds = %sw.bb73
+    br label %while.body83
+
+  while.body83:                                     ; preds = %while.body83.preheader, %while.body83
+    %call87 = tail call i32 @foo3(i32* null)
+    br label %while.body83
+
+  while.end88:                                      ; preds = %sw.bb73
+    %call89 = tail call i32 @foo2(i32 %call)
+    unreachable
+
+  sw.bb91:                                          ; preds = %entry
+    store i32 1, i32* %ignore_ptr, align 4
+    br label %cleanup
+
+  sw.bb93:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb94:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb95:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb96:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb97:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb98:                                          ; preds = %entry
+    br label %cleanup
+
+  sw.bb106:                                         ; preds = %entry
+    br label %cleanup
+
+  sw.bb107:                                         ; preds = %entry, %entry
+    br i1 undef, label %cleanup, label %if.then109
+
+  if.then109:                                       ; preds = %sw.bb107
+    %call110 = tail call i32 bitcast (i32 (...)* @foo1 to i32 (i8*, i32)*)(i8* undef, i32 %call)
+    unreachable
+
+  sw.epilog:                                        ; preds = %entry
+    %call.off = add i32 %call, -32
+    unreachable
+
+  cleanup:                                          ; preds = %sw.bb107, %sw.bb106, %sw.bb98, %sw.bb97, %sw.bb96, %sw.bb95, %sw.bb94, %sw.bb93, %sw.bb91, %entry, %entry, %entry, %entry
+    %retval.0 = phi i32 [ 11, %sw.bb106 ], [ 7, %sw.bb98 ], [ 8, %sw.bb97 ], [ 12, %sw.bb96 ], [ 13, %sw.bb95 ], [ 9, %sw.bb94 ], [ 10, %sw.bb93 ], [ 0, %sw.bb91 ], [ %call, %entry ], [ %call, %entry ], [ %call, %entry ], [ 27, %sw.bb107 ], [ %call, %entry ]
+    ret i32 %retval.0
+  }
+
+  ; Function Attrs: nounwind
+  declare void @llvm.stackprotector(i8*, i8**) #1
+
+  attributes #0 = { nounwind optsize }
+  attributes #1 = { nounwind }
+
+...
+---
+name:            foo4
+alignment:       1
+tracksRegLiveness: true
+liveins:
+  - { reg: '$r0' }
+frameInfo:
+  stackSize:       8
+  maxAlignment:    4
+  adjustsStack:    true
+  hasCalls:        true
+  maxCallFrameSize: 0
+stack:
+  - { id: 0, type: spill-slot, offset: -4, size: 4, alignment: 4, stack-id: 0,
+      callee-saved-register: '$lr', callee-saved-restored: false }
+  - { id: 1, type: spill-slot, offset: -8, size: 4, alignment: 4, stack-id: 0,
+      callee-saved-register: '$r4' }
+jumpTable:
+  kind:            inline
+  entries:
+    - id:              0
+      blocks:          [ '%bb.28', '%bb.26', '%bb.26', '%bb.26', '%bb.26',
+                         '%bb.24', '%bb.23', '%bb.26', '%bb.26', '%bb.12',
+                         '%bb.22' ]
+    - id:              1
+      blocks:          [ '%bb.19', '%bb.26', '%bb.26', '%bb.26', '%bb.21',
+                         '%bb.26', '%bb.20', '%bb.26', '%bb.25', '%bb.26',
+                         '%bb.15' ]
+body:             |
+  bb.0.entry:
+    successors: %bb.1(0x42c8590b), %bb.9(0x3d37a6f5)
+    liveins: $r0, $r4, $lr
+
+    frame-setup tPUSH 14, $noreg, killed $r4, killed $lr, implicit-def $sp, implicit $sp
+    frame-setup CFI_INSTRUCTION def_cfa_offset 8
+    frame-setup CFI_INSTRUCTION offset $lr, -4
+    frame-setup CFI_INSTRUCTION offset $r4, -8
+    $r4 = tMOVSr $r0, implicit-def dead $cpsr
+    tBL 14, $noreg, @foo3, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit undef $r0, implicit-def $sp, implicit-def $r0
+    $r1 = tMOVSr $r0, implicit-def dead $cpsr
+    tCMPi8 $r0, 68, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.9, 12, killed $cpsr
+
+  bb.1.entry:
+    successors: %bb.2(0x20000000), %bb.7(0x60000000)
+    liveins: $r0, $r1, $r4
+
+    tCMPi8 renamable $r1, 47, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.2, 13, killed $cpsr
+
+  bb.7.entry:
+    successors: %bb.16(0x71c71c72), %bb.8(0x0e38e38e)
+    liveins: $r0, $r1
+
+    $r2 = tMOVSr $r1, implicit-def dead $cpsr
+    renamable $r2, dead $cpsr = tSUBi8 killed renamable $r2, 48, 14, $noreg
+    tCMPi8 killed renamable $r2, 8, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.8, 2, killed $cpsr
+
+  bb.16.sw.bb73:
+    successors: %bb.17(0x7fffffff), %bb.18(0x00000001)
+    liveins: $r0, $r1
+
+    renamable $r2, dead $cpsr = tMOVi8 7, 14, $noreg
+    renamable $r1, dead $cpsr = tBIC killed renamable $r1, killed renamable $r2, 14, $noreg
+    tCMPi8 killed renamable $r1, 48, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.18, 1, killed $cpsr
+
+  bb.17.while.body83:
+    renamable $r0, dead $cpsr = tMOVi8 0, 14, $noreg
+    tBL 14, $noreg, @foo3, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit $r0, implicit-def $sp, implicit-def dead $r0
+    tB %bb.17, 14, $noreg
+
+  bb.9.entry:
+    successors: %bb.10(0x45d1745d), %bb.29(0x3a2e8ba3)
+    liveins: $r0, $r1
+
+    $r2 = tMOVSr $r1, implicit-def dead $cpsr
+    renamable $r2, dead $cpsr = tSUBi8 killed renamable $r2, 92, 14, $noreg
+    tCMPi8 renamable $r2, 10, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.29, 9, killed $cpsr
+
+  bb.10.entry:
+    successors: %bb.11(0x15555555), %bb.14(0x6aaaaaab)
+    liveins: $r0, $r1
+
+    $r2 = tMOVSr $r1, implicit-def dead $cpsr
+    renamable $r2, dead $cpsr = tSUBi8 killed renamable $r2, 110, 14, $noreg
+    tCMPi8 renamable $r2, 10, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.11, 8, killed $cpsr
+
+  bb.14.entry:
+    successors: %bb.19(0x1999999a), %bb.26(0x00000000), %bb.21(0x1999999a), %bb.20(0x1999999a), %bb.25(0x1999999a), %bb.15(0x1999999a)
+    liveins: $r2
+
+    renamable $r0, dead $cpsr = tLSLri killed renamable $r2, 2, 14, $noreg
+    renamable $r1 = tLEApcrelJT %jump-table.1, 14, $noreg
+    renamable $r0 = tLDRr killed renamable $r1, killed renamable $r0, 14, $noreg :: (load 4 from jump-table)
+    tBR_JTr killed renamable $r0, %jump-table.1
+
+  bb.19.sw.bb93:
+    renamable $r1, dead $cpsr = tMOVi8 10, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.15.while.cond:
+    renamable $r0, dead $cpsr = tMOVi8 0, 14, $noreg
+    tBL 14, $noreg, @foo3, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit $r0, implicit-def $sp, implicit-def dead $r0
+    tB %bb.15, 14, $noreg
+
+  bb.29.entry:
+    successors: %bb.28(0x1999999a), %bb.26(0x00000000), %bb.24(0x1999999a), %bb.23(0x1999999a), %bb.12(0x1999999a), %bb.22(0x1999999a)
+    liveins: $r0, $r2
+
+    renamable $r1, dead $cpsr = tLSLri killed renamable $r2, 2, 14, $noreg
+    renamable $r2 = tLEApcrelJT %jump-table.0, 14, $noreg
+    renamable $r2 = tLDRr killed renamable $r2, killed renamable $r1, 14, $noreg :: (load 4 from jump-table)
+    $r1 = tMOVSr $r0, implicit-def dead $cpsr
+    tBR_JTr killed renamable $r2, %jump-table.0
+
+  bb.24.sw.bb98:
+    renamable $r1, dead $cpsr = tMOVi8 7, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.2.entry:
+    successors: %bb.27(0x2aaaaaab), %bb.3(0x55555555)
+    liveins: $r0, $r1, $r4
+
+    tCMPi8 renamable $r1, 10, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.27, 0, killed $cpsr
+
+  bb.3.entry:
+    successors: %bb.4, %bb.5
+    liveins: $r0, $r1
+
+    tCMPi8 renamable $r1, 34, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.5, 1, killed $cpsr
+
+  bb.4:
+    liveins: $r0
+
+    $r1 = tMOVSr killed $r0, implicit-def dead $cpsr
+    tB %bb.28, 14, $noreg
+
+  bb.25.sw.bb106:
+    renamable $r1, dead $cpsr = tMOVi8 11, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.23.sw.bb97:
+    renamable $r1, dead $cpsr = tMOVi8 8, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.27.sw.bb91:
+    liveins: $r4
+
+    renamable $r0, dead $cpsr = tMOVi8 1, 14, $noreg
+    tSTRi killed renamable $r0, killed renamable $r4, 0, 14, $noreg :: (store 4 into %ir.ignore_ptr)
+    renamable $r1, dead $cpsr = tMOVi8 0, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.21.sw.bb95:
+    renamable $r1, dead $cpsr = tMOVi8 13, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.20.sw.bb94:
+    renamable $r1, dead $cpsr = tMOVi8 9, 14, $noreg
+    tB %bb.28, 14, $noreg
+
+  bb.5.entry:
+    liveins: $r0, $r1
+
+    tCMPi8 killed renamable $r1, 39, 14, $noreg, implicit-def $cpsr
+    tB %bb.6, 14, $noreg
+
+  bb.11.entry:
+    successors: %bb.12(0x80000000), %bb.26(0x00000000)
+    liveins: $r0, $r1
+
+    tCMPi8 killed renamable $r1, 69, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.26, 1, killed $cpsr
+
+  bb.12.sw.bb107:
+    successors: %bb.28(0x7fffffff), %bb.13(0x00000001)
+    liveins: $r0
+
+    renamable $r1, dead $cpsr = tMOVi8 27, 14, $noreg
+    renamable $r2, dead $cpsr = tMOVi8 0, 14, $noreg
+    tCMPi8 killed renamable $r2, 0, 14, $noreg, implicit-def $cpsr
+    tBcc %bb.28, 1, killed $cpsr
+
+  bb.13.if.then109:
+    successors:
+    liveins: $r0
+
+    $r1 = tMOVSr killed $r0, implicit-def dead $cpsr
+    tBL 14, $noreg, @foo1, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit undef $r0, implicit $r1, implicit-def $sp, implicit-def dead $r0
+
+  bb.8.entry:
+    liveins: $r0, $r1
+
+    tCMPi8 killed renamable $r1, 63, 14, $noreg, implicit-def $cpsr
+
+  bb.6.entry:
+    successors: %bb.28(0x80000000), %bb.26(0x00000000)
+    liveins: $cpsr, $r0
+
+    tPUSH 14, $noreg, killed $r0, implicit-def $sp, implicit $sp
+    tPOP 14, $noreg, def $r1, implicit-def $sp, implicit $sp
+    tBcc %bb.28, 0, killed $cpsr
+
+  bb.26.sw.epilog:
+    successors:
+
+
+  bb.22.sw.bb96:
+    renamable $r1, dead $cpsr = tMOVi8 12, 14, $noreg
+
+  bb.28.cleanup:
+    liveins: $r1
+
+    $r0 = tMOVSr killed $r1, implicit-def dead $cpsr
+    tPOP_RET 14, $noreg, def $r4, def $pc, implicit-def $sp, implicit $sp, implicit $r0
+
+  bb.18.while.end88:
+    liveins: $r0
+
+    tBL 14, $noreg, @foo2, csr_aapcs, implicit-def dead $lr, implicit $sp, implicit $r0, implicit-def $sp, implicit-def dead $r0
+
+...