[ARM] Constant pools need 4-byte alignment if we only have tADR

[john.brawn]

Summary

When the only ADR instruction we have is the 16-bit thumb one then all constant pool entries need to be 4-byte aligned, as tADR has an offset that's a multiple of 4.

It looks like previously there happened to be no situations in which we encountered a constant pool entry with alignment less than 4, so failing to do this didn't cause any problems, but the expansion of cttz to a table does use a constant pool with alignment 1, so we now need to handle it correctly.

[labrinea]

the expansion of cttz to a table

Can you explain what that means?

How does the test demostrate the difference in alignment compared to the old codegen? Is it the .p2align 2 directive?

[john.brawn]

In D133199#3769823, @labrinea wrote:

the expansion of cttz to a table

Can you explain what that means?

D128911 made cttz be expanded to a table lookup, with the table being placed in a constant pool.

How does the test demostrate the difference in alignment compared to the old codegen? Is it the .p2align 2 directive?

Yes, it's the .p2align 2. Without that if you try to generate an object (https://godbolt.org/z/hdGsPccn8) you get "error: misaligned pc-relative fixup value".

[labrinea]

Ok, I looked at the other patch; it'd be helpful to mention it on the description. This change seems fine. Thanks.

[dmgreen]

I was expecting this to be in ConstantIslandPass, but this sounds OK. LGTM, thanks for the fix.

llvm/lib/Target/ARM/ARMISelLowering.cpp

auto GV = new GlobalVariable(
                     Twine(DAG.getMachineFunction().getFunctionNumber()) + "_" +
                     Twine(AFI->createPICLabelUId())
                   );
     SDValue GA = DAG.getTargetGlobalAddress(dyn_cast<GlobalValue>(GV),
                                             dl, PtrVT);
     return LowerGlobalAddress(GA, DAG);
   }
 
+  // The 16-bit ADR instruction can only encode offsets that are multiples of 4,
+  // so we need to align to at least 4 bytes when we don't have 32-bit ADR.
+  Align CPAlign = CP->getAlign();
+  if (Subtarget->isThumb1Only())
+    CPAlign = std::max(CPAlign, Align(4));
   if (CP->isMachineConstantPoolEntry())
     Res =
-        DAG.getTargetConstantPool(CP->getMachineCPVal(), PtrVT, CP->getAlign());
+        DAG.getTargetConstantPool(CP->getMachineCPVal(), PtrVT, CPAlign);
   else
-    Res = DAG.getTargetConstantPool(CP->getConstVal(), PtrVT, CP->getAlign());
+    Res = DAG.getTargetConstantPool(CP->getConstVal(), PtrVT, CPAlign);
   return DAG.getNode(ARMISD::Wrapper, dl, MVT::i32, Res);
 }
 
 unsigned ARMTargetLowering::getJumpTableEncoding() const {
   return MachineJumpTableInfo::EK_Inline;
 }
 
 SDValue ARMTargetLowering::LowerBlockAddress(SDValue Op,

llvm/test/CodeGen/ARM/cttz.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple arm-eabi -mattr=+v6t2 | FileCheck %s
 ; RUN: llc < %s -mtriple arm-eabi -mattr=+v6t2 -mattr=+neon | FileCheck %s
-; RUN: llc < %s -mtriple thumbv6m-none-eabi | FileCheck %s --check-prefix=CHECK-THUMB
+; RUN: llc < %s -mtriple thumbv6m-none-eabi | FileCheck %s --check-prefix=CHECK-6M
+; RUN: llc < %s -mtriple thumbv8m.base-none-eabi | FileCheck %s --check-prefix=CHECK-8MBASE
 
 ; This test checks the @llvm.cttz.* intrinsics for integers.
 
 declare i8 @llvm.cttz.i8(i8, i1)
 declare i16 @llvm.cttz.i16(i16, i1)
 declare i32 @llvm.cttz.i32(i32, i1)
 declare i64 @llvm.cttz.i64(i64, i1)
 
 ;------------------------------------------------------------------------------
 
 define i8 @test_i8(i8 %a) {
 ; CHECK-LABEL: test_i8:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    orr r0, r0, #256
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i8:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    lsls r1, r0, #24
-; CHECK-THUMB-NEXT:    beq .LBB0_3
-; CHECK-THUMB-NEXT:  @ %bb.1: @ %cond.false
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB0_4
-; CHECK-THUMB-NEXT:  @ %bb.2: @ %cond.false
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI0_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI0_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB0_3:
-; CHECK-THUMB-NEXT:    movs r0, #8
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB0_4:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.5:
-; CHECK-THUMB-NEXT:  .LCPI0_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI0_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i8:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    lsls r1, r0, #24
+; CHECK-6M-NEXT:    beq .LBB0_3
+; CHECK-6M-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB0_4
+; CHECK-6M-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI0_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI0_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB0_3:
+; CHECK-6M-NEXT:    movs r0, #8
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB0_4:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.5:
+; CHECK-6M-NEXT:  .LCPI0_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI0_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i8:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    lsls r1, r0, #24
+; CHECK-8MBASE-NEXT:    beq .LBB0_3
+; CHECK-8MBASE-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB0_4
+; CHECK-8MBASE-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI0_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB0_3:
+; CHECK-8MBASE-NEXT:    movs r0, #8
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB0_4:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.5:
+; CHECK-8MBASE-NEXT:  .LCPI0_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i8 @llvm.cttz.i8(i8 %a, i1 false)
   ret i8 %tmp
 }
 
 define i16 @test_i16(i16 %a) {
 ; CHECK-LABEL: test_i16:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    orr r0, r0, #65536
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i16:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    lsls r1, r0, #16
-; CHECK-THUMB-NEXT:    beq .LBB1_3
-; CHECK-THUMB-NEXT:  @ %bb.1: @ %cond.false
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB1_4
-; CHECK-THUMB-NEXT:  @ %bb.2: @ %cond.false
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI1_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI1_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB1_3:
-; CHECK-THUMB-NEXT:    movs r0, #16
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB1_4:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.5:
-; CHECK-THUMB-NEXT:  .LCPI1_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI1_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i16:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    lsls r1, r0, #16
+; CHECK-6M-NEXT:    beq .LBB1_3
+; CHECK-6M-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB1_4
+; CHECK-6M-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI1_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI1_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB1_3:
+; CHECK-6M-NEXT:    movs r0, #16
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB1_4:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.5:
+; CHECK-6M-NEXT:  .LCPI1_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI1_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i16:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    lsls r1, r0, #16
+; CHECK-8MBASE-NEXT:    beq .LBB1_3
+; CHECK-8MBASE-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB1_4
+; CHECK-8MBASE-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI1_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB1_3:
+; CHECK-8MBASE-NEXT:    movs r0, #16
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB1_4:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.5:
+; CHECK-8MBASE-NEXT:  .LCPI1_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i16 @llvm.cttz.i16(i16 %a, i1 false)
   ret i16 %tmp
 }
 
 define i32 @test_i32(i32 %a) {
 ; CHECK-LABEL: test_i32:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i32:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB2_3
-; CHECK-THUMB-NEXT:  @ %bb.1: @ %cond.false
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB2_3
-; CHECK-THUMB-NEXT:  @ %bb.2: @ %cond.false
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI2_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI2_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB2_3:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.4:
-; CHECK-THUMB-NEXT:  .LCPI2_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI2_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i32:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB2_3
+; CHECK-6M-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB2_3
+; CHECK-6M-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI2_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI2_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB2_3:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.4:
+; CHECK-6M-NEXT:  .LCPI2_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI2_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i32:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB2_3
+; CHECK-8MBASE-NEXT:  @ %bb.1: @ %cond.false
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB2_3
+; CHECK-8MBASE-NEXT:  @ %bb.2: @ %cond.false
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI2_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB2_3:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.4:
+; CHECK-8MBASE-NEXT:  .LCPI2_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i32 @llvm.cttz.i32(i32 %a, i1 false)
   ret i32 %tmp
 }
 
 define i64 @test_i64(i64 %a) {
 ; CHECK-LABEL: test_i64:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r1, r1
 ; CHECK-NEXT:    rbit r2, r0
 ; CHECK-NEXT:    clz r1, r1
 ; CHECK-NEXT:    cmp r0, #0
 ; CHECK-NEXT:    add r1, r1, #32
 ; CHECK-NEXT:    clzne r1, r2
 ; CHECK-NEXT:    mov r0, r1
 ; CHECK-NEXT:    mov r1, #0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i64:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    .save {r4, r5, r7, lr}
-; CHECK-THUMB-NEXT:    push {r4, r5, r7, lr}
-; CHECK-THUMB-NEXT:    ldr r5, .LCPI3_0
-; CHECK-THUMB-NEXT:    adr r4, .LCPI3_1
-; CHECK-THUMB-NEXT:    movs r3, #32
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    mov r2, r3
-; CHECK-THUMB-NEXT:    bne .LBB3_5
-; CHECK-THUMB-NEXT:  @ %bb.1:
-; CHECK-THUMB-NEXT:    cmp r1, #0
-; CHECK-THUMB-NEXT:    bne .LBB3_6
-; CHECK-THUMB-NEXT:  .LBB3_2:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    bne .LBB3_4
-; CHECK-THUMB-NEXT:  .LBB3_3:
-; CHECK-THUMB-NEXT:    adds r3, #32
-; CHECK-THUMB-NEXT:    mov r2, r3
-; CHECK-THUMB-NEXT:  .LBB3_4:
-; CHECK-THUMB-NEXT:    movs r1, #0
-; CHECK-THUMB-NEXT:    mov r0, r2
-; CHECK-THUMB-NEXT:    pop {r4, r5, r7, pc}
-; CHECK-THUMB-NEXT:  .LBB3_5:
-; CHECK-THUMB-NEXT:    rsbs r2, r0, #0
-; CHECK-THUMB-NEXT:    ands r2, r0
-; CHECK-THUMB-NEXT:    muls r2, r5, r2
-; CHECK-THUMB-NEXT:    lsrs r2, r2, #27
-; CHECK-THUMB-NEXT:    ldrb r2, [r4, r2]
-; CHECK-THUMB-NEXT:    cmp r1, #0
-; CHECK-THUMB-NEXT:    beq .LBB3_2
-; CHECK-THUMB-NEXT:  .LBB3_6:
-; CHECK-THUMB-NEXT:    rsbs r3, r1, #0
-; CHECK-THUMB-NEXT:    ands r3, r1
-; CHECK-THUMB-NEXT:    muls r5, r3, r5
-; CHECK-THUMB-NEXT:    lsrs r1, r5, #27
-; CHECK-THUMB-NEXT:    ldrb r3, [r4, r1]
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB3_3
-; CHECK-THUMB-NEXT:    b .LBB3_4
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.7:
-; CHECK-THUMB-NEXT:  .LCPI3_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI3_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i64:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    .save {r4, r5, r7, lr}
+; CHECK-6M-NEXT:    push {r4, r5, r7, lr}
+; CHECK-6M-NEXT:    ldr r5, .LCPI3_0
+; CHECK-6M-NEXT:    adr r4, .LCPI3_1
+; CHECK-6M-NEXT:    movs r3, #32
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    mov r2, r3
+; CHECK-6M-NEXT:    bne .LBB3_5
+; CHECK-6M-NEXT:  @ %bb.1:
+; CHECK-6M-NEXT:    cmp r1, #0
+; CHECK-6M-NEXT:    bne .LBB3_6
+; CHECK-6M-NEXT:  .LBB3_2:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    bne .LBB3_4
+; CHECK-6M-NEXT:  .LBB3_3:
+; CHECK-6M-NEXT:    adds r3, #32
+; CHECK-6M-NEXT:    mov r2, r3
+; CHECK-6M-NEXT:  .LBB3_4:
+; CHECK-6M-NEXT:    movs r1, #0
+; CHECK-6M-NEXT:    mov r0, r2
+; CHECK-6M-NEXT:    pop {r4, r5, r7, pc}
+; CHECK-6M-NEXT:  .LBB3_5:
+; CHECK-6M-NEXT:    rsbs r2, r0, #0
+; CHECK-6M-NEXT:    ands r2, r0
+; CHECK-6M-NEXT:    muls r2, r5, r2
+; CHECK-6M-NEXT:    lsrs r2, r2, #27
+; CHECK-6M-NEXT:    ldrb r2, [r4, r2]
+; CHECK-6M-NEXT:    cmp r1, #0
+; CHECK-6M-NEXT:    beq .LBB3_2
+; CHECK-6M-NEXT:  .LBB3_6:
+; CHECK-6M-NEXT:    rsbs r3, r1, #0
+; CHECK-6M-NEXT:    ands r3, r1
+; CHECK-6M-NEXT:    muls r5, r3, r5
+; CHECK-6M-NEXT:    lsrs r1, r5, #27
+; CHECK-6M-NEXT:    ldrb r3, [r4, r1]
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB3_3
+; CHECK-6M-NEXT:    b .LBB3_4
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.7:
+; CHECK-6M-NEXT:  .LCPI3_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI3_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i64:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    .save {r4, r5, r7, lr}
+; CHECK-8MBASE-NEXT:    push {r4, r5, r7, lr}
+; CHECK-8MBASE-NEXT:    movw r5, #46385
+; CHECK-8MBASE-NEXT:    movt r5, #1916
+; CHECK-8MBASE-NEXT:    adr r4, .LCPI3_0
+; CHECK-8MBASE-NEXT:    movs r3, #32
+; CHECK-8MBASE-NEXT:    mov r2, r3
+; CHECK-8MBASE-NEXT:    cbnz r0, .LBB3_5
+; CHECK-8MBASE-NEXT:  @ %bb.1:
+; CHECK-8MBASE-NEXT:    cbnz r1, .LBB3_6
+; CHECK-8MBASE-NEXT:  .LBB3_2:
+; CHECK-8MBASE-NEXT:    cbnz r0, .LBB3_4
+; CHECK-8MBASE-NEXT:  .LBB3_3:
+; CHECK-8MBASE-NEXT:    adds r3, #32
+; CHECK-8MBASE-NEXT:    mov r2, r3
+; CHECK-8MBASE-NEXT:  .LBB3_4:
+; CHECK-8MBASE-NEXT:    movs r1, #0
+; CHECK-8MBASE-NEXT:    mov r0, r2
+; CHECK-8MBASE-NEXT:    pop {r4, r5, r7, pc}
+; CHECK-8MBASE-NEXT:  .LBB3_5:
+; CHECK-8MBASE-NEXT:    rsbs r2, r0, #0
+; CHECK-8MBASE-NEXT:    ands r2, r0
+; CHECK-8MBASE-NEXT:    muls r2, r5, r2
+; CHECK-8MBASE-NEXT:    lsrs r2, r2, #27
+; CHECK-8MBASE-NEXT:    ldrb r2, [r4, r2]
+; CHECK-8MBASE-NEXT:    cmp r1, #0
+; CHECK-8MBASE-NEXT:    beq .LBB3_2
+; CHECK-8MBASE-NEXT:  .LBB3_6:
+; CHECK-8MBASE-NEXT:    rsbs r3, r1, #0
+; CHECK-8MBASE-NEXT:    ands r3, r1
+; CHECK-8MBASE-NEXT:    muls r5, r3, r5
+; CHECK-8MBASE-NEXT:    lsrs r1, r5, #27
+; CHECK-8MBASE-NEXT:    ldrb r3, [r4, r1]
+; CHECK-8MBASE-NEXT:    cmp r0, #0
+; CHECK-8MBASE-NEXT:    beq .LBB3_3
+; CHECK-8MBASE-NEXT:    b .LBB3_4
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.7:
+; CHECK-8MBASE-NEXT:  .LCPI3_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i64 @llvm.cttz.i64(i64 %a, i1 false)
   ret i64 %tmp
 }
 
 ;------------------------------------------------------------------------------
 
 define i8 @test_i8_zero_undef(i8 %a) {
 ; CHECK-LABEL: test_i8_zero_undef:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i8_zero_undef:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB4_2
-; CHECK-THUMB-NEXT:  @ %bb.1:
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI4_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI4_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB4_2:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.3:
-; CHECK-THUMB-NEXT:  .LCPI4_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI4_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i8_zero_undef:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB4_2
+; CHECK-6M-NEXT:  @ %bb.1:
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI4_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI4_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB4_2:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.3:
+; CHECK-6M-NEXT:  .LCPI4_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI4_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i8_zero_undef:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB4_2
+; CHECK-8MBASE-NEXT:  @ %bb.1:
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI4_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB4_2:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.3:
+; CHECK-8MBASE-NEXT:  .LCPI4_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i8 @llvm.cttz.i8(i8 %a, i1 true)
   ret i8 %tmp
 }
 
 define i16 @test_i16_zero_undef(i16 %a) {
 ; CHECK-LABEL: test_i16_zero_undef:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i16_zero_undef:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB5_2
-; CHECK-THUMB-NEXT:  @ %bb.1:
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI5_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI5_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB5_2:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.3:
-; CHECK-THUMB-NEXT:  .LCPI5_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI5_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i16_zero_undef:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB5_2
+; CHECK-6M-NEXT:  @ %bb.1:
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI5_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI5_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB5_2:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.3:
+; CHECK-6M-NEXT:  .LCPI5_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI5_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i16_zero_undef:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB5_2
+; CHECK-8MBASE-NEXT:  @ %bb.1:
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI5_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB5_2:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.3:
+; CHECK-8MBASE-NEXT:  .LCPI5_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i16 @llvm.cttz.i16(i16 %a, i1 true)
   ret i16 %tmp
 }
 
 
 define i32 @test_i32_zero_undef(i32 %a) {
 ; CHECK-LABEL: test_i32_zero_undef:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r0, r0
 ; CHECK-NEXT:    clz r0, r0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i32_zero_undef:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB6_2
-; CHECK-THUMB-NEXT:  @ %bb.1:
-; CHECK-THUMB-NEXT:    rsbs r1, r0, #0
-; CHECK-THUMB-NEXT:    ands r1, r0
-; CHECK-THUMB-NEXT:    ldr r0, .LCPI6_0
-; CHECK-THUMB-NEXT:    muls r0, r1, r0
-; CHECK-THUMB-NEXT:    lsrs r0, r0, #27
-; CHECK-THUMB-NEXT:    adr r1, .LCPI6_1
-; CHECK-THUMB-NEXT:    ldrb r0, [r1, r0]
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:  .LBB6_2:
-; CHECK-THUMB-NEXT:    movs r0, #32
-; CHECK-THUMB-NEXT:    bx lr
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.3:
-; CHECK-THUMB-NEXT:  .LCPI6_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI6_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i32_zero_undef:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB6_2
+; CHECK-6M-NEXT:  @ %bb.1:
+; CHECK-6M-NEXT:    rsbs r1, r0, #0
+; CHECK-6M-NEXT:    ands r1, r0
+; CHECK-6M-NEXT:    ldr r0, .LCPI6_0
+; CHECK-6M-NEXT:    muls r0, r1, r0
+; CHECK-6M-NEXT:    lsrs r0, r0, #27
+; CHECK-6M-NEXT:    adr r1, .LCPI6_1
+; CHECK-6M-NEXT:    ldrb r0, [r1, r0]
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:  .LBB6_2:
+; CHECK-6M-NEXT:    movs r0, #32
+; CHECK-6M-NEXT:    bx lr
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.3:
+; CHECK-6M-NEXT:  .LCPI6_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI6_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i32_zero_undef:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    cbz r0, .LBB6_2
+; CHECK-8MBASE-NEXT:  @ %bb.1:
+; CHECK-8MBASE-NEXT:    rsbs r1, r0, #0
+; CHECK-8MBASE-NEXT:    ands r1, r0
+; CHECK-8MBASE-NEXT:    movw r0, #46385
+; CHECK-8MBASE-NEXT:    movt r0, #1916
+; CHECK-8MBASE-NEXT:    muls r0, r1, r0
+; CHECK-8MBASE-NEXT:    lsrs r0, r0, #27
+; CHECK-8MBASE-NEXT:    adr r1, .LCPI6_0
+; CHECK-8MBASE-NEXT:    ldrb r0, [r1, r0]
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:  .LBB6_2:
+; CHECK-8MBASE-NEXT:    movs r0, #32
+; CHECK-8MBASE-NEXT:    bx lr
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.3:
+; CHECK-8MBASE-NEXT:  .LCPI6_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i32 @llvm.cttz.i32(i32 %a, i1 true)
   ret i32 %tmp
 }
 
 define i64 @test_i64_zero_undef(i64 %a) {
 ; CHECK-LABEL: test_i64_zero_undef:
 ; CHECK:       @ %bb.0:
 ; CHECK-NEXT:    rbit r1, r1
 ; CHECK-NEXT:    rbit r2, r0
 ; CHECK-NEXT:    clz r1, r1
 ; CHECK-NEXT:    cmp r0, #0
 ; CHECK-NEXT:    add r1, r1, #32
 ; CHECK-NEXT:    clzne r1, r2
 ; CHECK-NEXT:    mov r0, r1
 ; CHECK-NEXT:    mov r1, #0
 ; CHECK-NEXT:    bx lr
 ;
-; CHECK-THUMB-LABEL: test_i64_zero_undef:
-; CHECK-THUMB:       @ %bb.0:
-; CHECK-THUMB-NEXT:    .save {r4, r5, r7, lr}
-; CHECK-THUMB-NEXT:    push {r4, r5, r7, lr}
-; CHECK-THUMB-NEXT:    ldr r5, .LCPI7_0
-; CHECK-THUMB-NEXT:    adr r4, .LCPI7_1
-; CHECK-THUMB-NEXT:    movs r3, #32
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    mov r2, r3
-; CHECK-THUMB-NEXT:    bne .LBB7_5
-; CHECK-THUMB-NEXT:  @ %bb.1:
-; CHECK-THUMB-NEXT:    cmp r1, #0
-; CHECK-THUMB-NEXT:    bne .LBB7_6
-; CHECK-THUMB-NEXT:  .LBB7_2:
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    bne .LBB7_4
-; CHECK-THUMB-NEXT:  .LBB7_3:
-; CHECK-THUMB-NEXT:    adds r3, #32
-; CHECK-THUMB-NEXT:    mov r2, r3
-; CHECK-THUMB-NEXT:  .LBB7_4:
-; CHECK-THUMB-NEXT:    movs r1, #0
-; CHECK-THUMB-NEXT:    mov r0, r2
-; CHECK-THUMB-NEXT:    pop {r4, r5, r7, pc}
-; CHECK-THUMB-NEXT:  .LBB7_5:
-; CHECK-THUMB-NEXT:    rsbs r2, r0, #0
-; CHECK-THUMB-NEXT:    ands r2, r0
-; CHECK-THUMB-NEXT:    muls r2, r5, r2
-; CHECK-THUMB-NEXT:    lsrs r2, r2, #27
-; CHECK-THUMB-NEXT:    ldrb r2, [r4, r2]
-; CHECK-THUMB-NEXT:    cmp r1, #0
-; CHECK-THUMB-NEXT:    beq .LBB7_2
-; CHECK-THUMB-NEXT:  .LBB7_6:
-; CHECK-THUMB-NEXT:    rsbs r3, r1, #0
-; CHECK-THUMB-NEXT:    ands r3, r1
-; CHECK-THUMB-NEXT:    muls r5, r3, r5
-; CHECK-THUMB-NEXT:    lsrs r1, r5, #27
-; CHECK-THUMB-NEXT:    ldrb r3, [r4, r1]
-; CHECK-THUMB-NEXT:    cmp r0, #0
-; CHECK-THUMB-NEXT:    beq .LBB7_3
-; CHECK-THUMB-NEXT:    b .LBB7_4
-; CHECK-THUMB-NEXT:    .p2align 2
-; CHECK-THUMB-NEXT:  @ %bb.7:
-; CHECK-THUMB-NEXT:  .LCPI7_0:
-; CHECK-THUMB-NEXT:    .long 125613361 @ 0x77cb531
-; CHECK-THUMB-NEXT:  .LCPI7_1:
-; CHECK-THUMB-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+; CHECK-6M-LABEL: test_i64_zero_undef:
+; CHECK-6M:       @ %bb.0:
+; CHECK-6M-NEXT:    .save {r4, r5, r7, lr}
+; CHECK-6M-NEXT:    push {r4, r5, r7, lr}
+; CHECK-6M-NEXT:    ldr r5, .LCPI7_0
+; CHECK-6M-NEXT:    adr r4, .LCPI7_1
+; CHECK-6M-NEXT:    movs r3, #32
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    mov r2, r3
+; CHECK-6M-NEXT:    bne .LBB7_5
+; CHECK-6M-NEXT:  @ %bb.1:
+; CHECK-6M-NEXT:    cmp r1, #0
+; CHECK-6M-NEXT:    bne .LBB7_6
+; CHECK-6M-NEXT:  .LBB7_2:
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    bne .LBB7_4
+; CHECK-6M-NEXT:  .LBB7_3:
+; CHECK-6M-NEXT:    adds r3, #32
+; CHECK-6M-NEXT:    mov r2, r3
+; CHECK-6M-NEXT:  .LBB7_4:
+; CHECK-6M-NEXT:    movs r1, #0
+; CHECK-6M-NEXT:    mov r0, r2
+; CHECK-6M-NEXT:    pop {r4, r5, r7, pc}
+; CHECK-6M-NEXT:  .LBB7_5:
+; CHECK-6M-NEXT:    rsbs r2, r0, #0
+; CHECK-6M-NEXT:    ands r2, r0
+; CHECK-6M-NEXT:    muls r2, r5, r2
+; CHECK-6M-NEXT:    lsrs r2, r2, #27
+; CHECK-6M-NEXT:    ldrb r2, [r4, r2]
+; CHECK-6M-NEXT:    cmp r1, #0
+; CHECK-6M-NEXT:    beq .LBB7_2
+; CHECK-6M-NEXT:  .LBB7_6:
+; CHECK-6M-NEXT:    rsbs r3, r1, #0
+; CHECK-6M-NEXT:    ands r3, r1
+; CHECK-6M-NEXT:    muls r5, r3, r5
+; CHECK-6M-NEXT:    lsrs r1, r5, #27
+; CHECK-6M-NEXT:    ldrb r3, [r4, r1]
+; CHECK-6M-NEXT:    cmp r0, #0
+; CHECK-6M-NEXT:    beq .LBB7_3
+; CHECK-6M-NEXT:    b .LBB7_4
+; CHECK-6M-NEXT:    .p2align 2
+; CHECK-6M-NEXT:  @ %bb.7:
+; CHECK-6M-NEXT:  .LCPI7_0:
+; CHECK-6M-NEXT:    .long 125613361 @ 0x77cb531
+; CHECK-6M-NEXT:  .LCPI7_1:
+; CHECK-6M-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
+;
+; CHECK-8MBASE-LABEL: test_i64_zero_undef:
+; CHECK-8MBASE:       @ %bb.0:
+; CHECK-8MBASE-NEXT:    .save {r4, r5, r7, lr}
+; CHECK-8MBASE-NEXT:    push {r4, r5, r7, lr}
+; CHECK-8MBASE-NEXT:    movw r5, #46385
+; CHECK-8MBASE-NEXT:    movt r5, #1916
+; CHECK-8MBASE-NEXT:    adr r4, .LCPI7_0
+; CHECK-8MBASE-NEXT:    movs r3, #32
+; CHECK-8MBASE-NEXT:    mov r2, r3
+; CHECK-8MBASE-NEXT:    cbnz r0, .LBB7_5
+; CHECK-8MBASE-NEXT:  @ %bb.1:
+; CHECK-8MBASE-NEXT:    cbnz r1, .LBB7_6
+; CHECK-8MBASE-NEXT:  .LBB7_2:
+; CHECK-8MBASE-NEXT:    cbnz r0, .LBB7_4
+; CHECK-8MBASE-NEXT:  .LBB7_3:
+; CHECK-8MBASE-NEXT:    adds r3, #32
+; CHECK-8MBASE-NEXT:    mov r2, r3
+; CHECK-8MBASE-NEXT:  .LBB7_4:
+; CHECK-8MBASE-NEXT:    movs r1, #0
+; CHECK-8MBASE-NEXT:    mov r0, r2
+; CHECK-8MBASE-NEXT:    pop {r4, r5, r7, pc}
+; CHECK-8MBASE-NEXT:  .LBB7_5:
+; CHECK-8MBASE-NEXT:    rsbs r2, r0, #0
+; CHECK-8MBASE-NEXT:    ands r2, r0
+; CHECK-8MBASE-NEXT:    muls r2, r5, r2
+; CHECK-8MBASE-NEXT:    lsrs r2, r2, #27
+; CHECK-8MBASE-NEXT:    ldrb r2, [r4, r2]
+; CHECK-8MBASE-NEXT:    cmp r1, #0
+; CHECK-8MBASE-NEXT:    beq .LBB7_2
+; CHECK-8MBASE-NEXT:  .LBB7_6:
+; CHECK-8MBASE-NEXT:    rsbs r3, r1, #0
+; CHECK-8MBASE-NEXT:    ands r3, r1
+; CHECK-8MBASE-NEXT:    muls r5, r3, r5
+; CHECK-8MBASE-NEXT:    lsrs r1, r5, #27
+; CHECK-8MBASE-NEXT:    ldrb r3, [r4, r1]
+; CHECK-8MBASE-NEXT:    cmp r0, #0
+; CHECK-8MBASE-NEXT:    beq .LBB7_3
+; CHECK-8MBASE-NEXT:    b .LBB7_4
+; CHECK-8MBASE-NEXT:    .p2align 2
+; CHECK-8MBASE-NEXT:  @ %bb.7:
+; CHECK-8MBASE-NEXT:  .LCPI7_0:
+; CHECK-8MBASE-NEXT:    .ascii "\000\001\034\002\035\016\030\003\036\026\024\017\031\021\004\b\037\033\r\027\025\023\020\007\032\f\022\006\013\005\n\t"
   %tmp = call i64 @llvm.cttz.i64(i64 %a, i1 true)
   ret i64 %tmp
 }