diff --git a/llvm/lib/CodeGen/BranchRelaxation.cpp b/llvm/lib/CodeGen/BranchRelaxation.cpp
--- a/llvm/lib/CodeGen/BranchRelaxation.cpp
+++ b/llvm/lib/CodeGen/BranchRelaxation.cpp
@@ -79,6 +79,9 @@
   };
 
   SmallVector<BasicBlockInfo, 16> BlockInfo;
+  MachineBasicBlock *TrampolineInsertionPoint;
+  SmallDenseSet<std::pair<MachineBasicBlock *, MachineBasicBlock *>>
+      RelaxedUnconditionals;
   std::unique_ptr<RegScavenger> RS;
   LivePhysRegs LiveRegs;
 
@@ -144,7 +147,8 @@
       if (MI.getOpcode() == TargetOpcode::FAULTING_OP)
         continue;
       MachineBasicBlock *DestBB = TII->getBranchDestBlock(MI);
-      assert(isBlockInRange(MI, *DestBB));
+      assert(isBlockInRange(MI, *DestBB) ||
+             RelaxedUnconditionals.contains({&MBB, DestBB}));
     }
   }
 #endif
@@ -167,6 +171,9 @@
   BlockInfo.clear();
   BlockInfo.resize(MF->getNumBlockIDs());
 
+  TrampolineInsertionPoint = nullptr;
+  RelaxedUnconditionals.clear();
+
   // First thing, compute the size of all basic blocks, and see if the function
   // has any inline assembly in it. If so, we have to be conservative about
   // alignment assumptions, as we don't know for sure the size of any
@@ -176,6 +183,15 @@
 
   // Compute block offsets and known bits.
   adjustBlockOffsets(*MF->begin());
+
+  // Place the trampoline insertion point at the end of the hot portion of the
+  // function.
+  for (MachineBasicBlock &MBB : reverse(*MF)) {
+    if (MBB.getSectionID() != MBBSectionID::ColdSectionID) {
+      TrampolineInsertionPoint = &MBB;
+      break;
+    }
+  }
 }
 
 /// computeBlockSize - Compute the size for MBB.
@@ -503,6 +519,8 @@
     BranchBB->sortUniqueLiveIns();
     BranchBB->addSuccessor(DestBB);
     MBB->replaceSuccessor(DestBB, BranchBB);
+    if (TrampolineInsertionPoint == MBB)
+      TrampolineInsertionPoint = BranchBB;
   }
 
   DebugLoc DL = MI.getDebugLoc();
@@ -528,6 +546,24 @@
 
   // If RestoreBB is required, try to place just before DestBB.
   if (!RestoreBB->empty()) {
+    if (MBB->getSectionID() == MBBSectionID::ColdSectionID && MBB &&
+        DestBB->getSectionID() != MBBSectionID::ColdSectionID) {
+      // If the jump is Cold -> Hot, then don't place the restore block in
+      // the middle of the function. Place it at the end.
+      MachineBasicBlock *NewBB = createNewBlockAfter(*TrampolineInsertionPoint);
+      TII->insertUnconditionalBranch(*NewBB, DestBB, DebugLoc());
+      BlockInfo[NewBB->getNumber()].Size = computeBlockSize(*NewBB);
+
+      // New trampolines should be inserted after NewBB
+      TrampolineInsertionPoint = NewBB;
+
+      // Retarget the unconditional branch to the trampoline block
+      BranchBB->replaceSuccessor(DestBB, NewBB);
+      NewBB->addSuccessor(DestBB);
+
+      DestBB = NewBB;
+    }
+
     // TODO: For multiple far branches to the same destination, there are
     // chances that some restore blocks could be shared if they clobber the
     // same registers and share the same restore sequence. So far, those
@@ -557,9 +593,11 @@
     RestoreBB->setSectionID(DestBB->getSectionID());
     RestoreBB->setIsBeginSection(DestBB->isBeginSection());
     DestBB->setIsBeginSection(false);
+    RelaxedUnconditionals.insert({BranchBB, RestoreBB});
   } else {
     // Remove restore block if it's not required.
     MF->erase(RestoreBB);
+    RelaxedUnconditionals.insert({BranchBB, DestBB});
   }
 
   return true;
@@ -585,7 +623,8 @@
       // Unconditional branch destination might be unanalyzable, assume these
       // are OK.
       if (MachineBasicBlock *DestBB = TII->getBranchDestBlock(*Last)) {
-        if (!isBlockInRange(*Last, *DestBB) && !TII->isTailCall(*Last)) {
+        if (!isBlockInRange(*Last, *DestBB) && !TII->isTailCall(*Last) &&
+            !RelaxedUnconditionals.contains({&MBB, DestBB})) {
           fixupUnconditionalBranch(*Last);
           ++NumUnconditionalRelaxed;
           Changed = true;
@@ -665,6 +704,8 @@
   LLVM_DEBUG(dbgs() << "  Basic blocks after relaxation\n\n"; dumpBBs());
 
   BlockInfo.clear();
+  TrampolineInsertionPoint = nullptr;
+  RelaxedUnconditionals.clear();
 
   return MadeChange;
 }
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -270,10 +270,20 @@
   };
 
   RS->enterBasicBlockEnd(MBB);
-  Register Reg = RS->FindUnusedReg(&AArch64::GPR64RegClass);
+  // If X16 is unused, then we can rely on the linker to safely insert the
+  // indirect branch.
+  Register Reg = AArch64::X16;
+  if (!RS->isRegUsed(Reg)) {
+    insertUnconditionalBranch(MBB, &NewDestBB, DL);
+    RS->setRegUsed(Reg);
+    return;
+  }
 
-  // If there's a free register, manually insert the indirect branch using it.
-  if (Reg != AArch64::NoRegister) {
+  // If there's a free register and it's worth inflating the code size,
+  // manually insert the indirect branch.
+  Reg = RS->FindUnusedReg(&AArch64::GPR64RegClass);
+  if (Reg != AArch64::NoRegister &&
+      MBB.getSectionID() == MBBSectionID::ColdSectionID) {
     buildIndirectBranch(Reg, NewDestBB);
     RS->setRegUsed(Reg);
     return;
@@ -285,7 +295,7 @@
   if (!AFI || AFI->hasRedZone().value_or(true))
     report_fatal_error(
         "Unable to insert indirect branch inside function that has red zone");
-
+  // Spill X16 so that the linker can safely insert the indirect branch.
   Reg = AArch64::X16;
   BuildMI(MBB, MBB.end(), DL, get(AArch64::STRXpre))
       .addReg(AArch64::SP, RegState::Define)
@@ -293,7 +303,7 @@
       .addReg(AArch64::SP)
       .addImm(-16);
 
-  buildIndirectBranch(Reg, RestoreBB);
+  BuildMI(MBB, MBB.end(), DL, get(AArch64::B)).addMBB(&RestoreBB);
 
   BuildMI(RestoreBB, RestoreBB.end(), DL, get(AArch64::LDRXpost))
       .addReg(AArch64::SP, RegState::Define)
diff --git a/llvm/test/CodeGen/AArch64/branch-relax-b.ll b/llvm/test/CodeGen/AArch64/branch-relax-b.ll
--- a/llvm/test/CodeGen/AArch64/branch-relax-b.ll
+++ b/llvm/test/CodeGen/AArch64/branch-relax-b.ll
@@ -6,9 +6,7 @@
 ; CHECK-NEXT:    tbnz w0,
 ; CHECK-SAME:                 LBB0_1
 ; CHECK-NEXT:  // %bb.3:                               // %entry
-; CHECK-NEXT:          adrp    [[SCAVENGED_REGISTER:x[0-9]+]], .LBB0_2
-; CHECK-NEXT:          add     [[SCAVENGED_REGISTER]], [[SCAVENGED_REGISTER]], :lo12:.LBB0_2
-; CHECK-NEXT:          br      [[SCAVENGED_REGISTER]]
+; CHECK-NEXT:          b      .LBB0_2
 ; CHECK-NEXT:  .LBB0_1:                                // %iftrue
 ; CHECK-NEXT:          //APP
 ; CHECK-NEXT:          .zero   2048
@@ -44,9 +42,7 @@
 ; CHECK-NEXT:     // %bb.4:                               // %entry
 ; CHECK-NEXT:             str     [[SPILL_REGISTER:x[0-9]+]], [sp,
 ; CHECK-SAME:                                                       -16]!
-; CHECK-NEXT:             adrp    [[SPILL_REGISTER:x[0-9]+]], .LBB1_5
-; CHECK-NEXT:             add     [[SPILL_REGISTER:x[0-9]+]], [[SPILL_REGISTER:x[0-9]+]], :lo12:.LBB1_5
-; CHECK-NEXT:             br      [[SPILL_REGISTER:x[0-9]+]]
+; CHECK-NEXT:             b       .LBB1_5
 ; CHECK-NEXT:     .LBB1_1:                                // %iftrue
 ; CHECK-NEXT:             //APP
 ; CHECK-NEXT:             .zero   2048
@@ -135,5 +131,44 @@
   ret void
 }
 
+define void @relax_b_x16_taken() {
+; CHECK-LABEL:    relax_b_x16_taken:                      // @relax_b_x16_taken
+; CHECK:          // %bb.0:                               // %entry
+; CHECK-NEXT:             //APP
+; CHECK-NEXT:             mov     x16, #1
+; CHECK-NEXT:             //NO_APP
+; CHECK-NEXT:             cbnz    x16, .LBB2_1
+; CHECK-NEXT:     // %bb.3:                               // %entry
+; CHECK-NEXT:             str     x16, [sp,
+; CHECK-SAME:                                                       -16]!
+; CHECK-NEXT:             b       .LBB2_4
+; CHECK-NEXT:     .LBB2_1:                                // %iftrue
+; CHECK-NEXT:             //APP
+; CHECK-NEXT:             .zero   2048
+; CHECK-NEXT:             //NO_APP
+; CHECK-NEXT:             ret
+; CHECK-NEXT:     .LBB2_4:                                // %iffalse
+; CHECK-NEXT:             ldr     x16, [sp], 
+; CHECK-SAME:                                                        16
+; CHECK-NEXT:     // %bb.2:                               // %iffalse
+; CHECK-NEXT:             //APP
+; CHECK-NEXT:             // reg use x16
+; CHECK-NEXT:             //NO_APP
+; CHECK-NEXT:             ret
+entry:
+  %x16 = call i64 asm sideeffect "mov x16, 1", "={x16}"()
+
+  %cmp = icmp eq i64 %x16, 0
+  br i1 %cmp, label %iffalse, label %iftrue
+
+iftrue:
+  call void asm sideeffect ".space 2048", ""()
+  ret void
+
+iffalse:
+  call void asm sideeffect "# reg use $0", "{x16}"(i64 %x16)
+  ret void
+}
+
 declare i32 @bar()
 declare i32 @baz()
\ No newline at end of file
diff --git a/llvm/test/CodeGen/AArch64/branch-relax-cross-section.mir b/llvm/test/CodeGen/AArch64/branch-relax-cross-section.mir
--- a/llvm/test/CodeGen/AArch64/branch-relax-cross-section.mir
+++ b/llvm/test/CodeGen/AArch64/branch-relax-cross-section.mir
@@ -1,4 +1,4 @@
-# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass branch-relaxation -aarch64-b-offset-bits=64 %s -o - | FileCheck %s
+# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass branch-relaxation %s -o - | FileCheck %s
 
 --- |
   target triple = "aarch64-unknown-linux-gnu"
@@ -22,6 +22,90 @@
     %4 = call i32 @bar()
     br label %end
   }
+
+  define void @x16_used_cold_to_hot() {
+  entry:
+    %x16 = call i64 asm sideeffect "mov x16, 1", "={x16}"()
+    %cmp = icmp eq i64 %x16, 0
+    br i1 %cmp, label %iffalse, label %iftrue
+  
+  iftrue:                                           ; preds = %entry
+    call void asm sideeffect ".space 4", ""()
+    br label %iffalse
+  
+  iffalse:                                          ; preds = %iftrue, %entry
+    call void asm sideeffect "# reg use $0", "{x16}"(i64 %x16)
+    ret void
+  }
+
+  define void @all_used_cold_to_hot() {
+  entry:
+    %x0 = call i64 asm sideeffect "mov x0, 1", "={x0}"()
+    %x1 = call i64 asm sideeffect "mov x1, 1", "={x1}"()
+    %x2 = call i64 asm sideeffect "mov x2, 1", "={x2}"()
+    %x3 = call i64 asm sideeffect "mov x3, 1", "={x3}"()
+    %x4 = call i64 asm sideeffect "mov x4, 1", "={x4}"()
+    %x5 = call i64 asm sideeffect "mov x5, 1", "={x5}"()
+    %x6 = call i64 asm sideeffect "mov x6, 1", "={x6}"()
+    %x7 = call i64 asm sideeffect "mov x7, 1", "={x7}"()
+    %x8 = call i64 asm sideeffect "mov x8, 1", "={x8}"()
+    %x9 = call i64 asm sideeffect "mov x9, 1", "={x9}"()
+    %x10 = call i64 asm sideeffect "mov x10, 1", "={x10}"()
+    %x11 = call i64 asm sideeffect "mov x11, 1", "={x11}"()
+    %x12 = call i64 asm sideeffect "mov x12, 1", "={x12}"()
+    %x13 = call i64 asm sideeffect "mov x13, 1", "={x13}"()
+    %x14 = call i64 asm sideeffect "mov x14, 1", "={x14}"()
+    %x15 = call i64 asm sideeffect "mov x15, 1", "={x15}"()
+    %x17 = call i64 asm sideeffect "mov x17, 1", "={x17}"()
+    %x18 = call i64 asm sideeffect "mov x18, 1", "={x18}"()
+    %x19 = call i64 asm sideeffect "mov x19, 1", "={x19}"()
+    %x20 = call i64 asm sideeffect "mov x20, 1", "={x20}"()
+    %x21 = call i64 asm sideeffect "mov x21, 1", "={x21}"()
+    %x22 = call i64 asm sideeffect "mov x22, 1", "={x22}"()
+    %x23 = call i64 asm sideeffect "mov x23, 1", "={x23}"()
+    %x24 = call i64 asm sideeffect "mov x24, 1", "={x24}"()
+    %x25 = call i64 asm sideeffect "mov x25, 1", "={x25}"()
+    %x26 = call i64 asm sideeffect "mov x26, 1", "={x26}"()
+    %x27 = call i64 asm sideeffect "mov x27, 1", "={x27}"()
+    %x28 = call i64 asm sideeffect "mov x28, 1", "={x28}"()
+    br label %cold
+  
+  cold:                                             ; preds = %entry
+    %x16 = call i64 asm sideeffect "mov x16, 1", "={x16}"()
+    br label %exit
+  
+  exit:                                             ; preds = %cold
+    call void asm sideeffect "# reg use $0", "{x0}"(i64 %x0)
+    call void asm sideeffect "# reg use $0", "{x1}"(i64 %x1)
+    call void asm sideeffect "# reg use $0", "{x2}"(i64 %x2)
+    call void asm sideeffect "# reg use $0", "{x3}"(i64 %x3)
+    call void asm sideeffect "# reg use $0", "{x4}"(i64 %x4)
+    call void asm sideeffect "# reg use $0", "{x5}"(i64 %x5)
+    call void asm sideeffect "# reg use $0", "{x6}"(i64 %x6)
+    call void asm sideeffect "# reg use $0", "{x7}"(i64 %x7)
+    call void asm sideeffect "# reg use $0", "{x8}"(i64 %x8)
+    call void asm sideeffect "# reg use $0", "{x9}"(i64 %x9)
+    call void asm sideeffect "# reg use $0", "{x10}"(i64 %x10)
+    call void asm sideeffect "# reg use $0", "{x11}"(i64 %x11)
+    call void asm sideeffect "# reg use $0", "{x12}"(i64 %x12)
+    call void asm sideeffect "# reg use $0", "{x13}"(i64 %x13)
+    call void asm sideeffect "# reg use $0", "{x14}"(i64 %x14)
+    call void asm sideeffect "# reg use $0", "{x15}"(i64 %x15)
+    call void asm sideeffect "# reg use $0", "{x16}"(i64 %x16)
+    call void asm sideeffect "# reg use $0", "{x17}"(i64 %x17)
+    call void asm sideeffect "# reg use $0", "{x18}"(i64 %x18)
+    call void asm sideeffect "# reg use $0", "{x19}"(i64 %x19)
+    call void asm sideeffect "# reg use $0", "{x20}"(i64 %x20)
+    call void asm sideeffect "# reg use $0", "{x21}"(i64 %x21)
+    call void asm sideeffect "# reg use $0", "{x22}"(i64 %x22)
+    call void asm sideeffect "# reg use $0", "{x23}"(i64 %x23)
+    call void asm sideeffect "# reg use $0", "{x24}"(i64 %x24)
+    call void asm sideeffect "# reg use $0", "{x25}"(i64 %x25)
+    call void asm sideeffect "# reg use $0", "{x26}"(i64 %x26)
+    call void asm sideeffect "# reg use $0", "{x27}"(i64 %x27)
+    call void asm sideeffect "# reg use $0", "{x28}"(i64 %x28)
+    ret void
+  }
   
   attributes #0 = { nounwind }
 
@@ -73,3 +157,259 @@
     early-clobber $sp, $lr = frame-destroy LDRXpost $sp, 16 :: (load (s64) from %stack.0)
     TCRETURNdi @qux, 0, csr_aarch64_aapcs, implicit $sp
 ...
+---
+name:            x16_used_cold_to_hot
+tracksRegLiveness: true
+liveins:         []
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  ; CHECK-LABEL: name: x16_used_cold_to_hot
+  ; COM: Check that unconditional branches from the cold section to
+  ; COM: the hot section manually insert indirect branches if x16
+  ; COM: isn't available but there is still a free register.
+  ; CHECK:       bb.0.entry:
+  ; CHECK-NEXT:    successors: %bb.1(0x40000000), %bb.3(0x40000000)
+  ; CHECK:         TBZW killed renamable $w8, 0, %bb.1
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:  bb.3.entry:
+  ; CHECK-NEXT:    successors: %bb.4(0x80000000)
+  ; CHECK-NEXT:    liveins: $x16
+  ; CHECK:         B %bb.4
+  ; CHECK:       bb.1.iffalse:
+  ; CHECK-NEXT:    liveins: $x16
+  ; CHECK:           killed $x16
+  ; CHECK:         RET undef $lr
+  ; CHECK:       bb.4.iftrue (bbsections Cold):
+  ; CHECK-NEXT:    successors: %bb.2(0x80000000)
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:    early-clobber $sp, $x16 = LDRXpost $sp, 16
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:  bb.2.iftrue (bbsections Cold):
+  ; CHECK-NEXT:    successors: %bb.5(0x80000000)
+  ; CHECK-NEXT:    liveins: $x16
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:    INLINEASM &".space 4", 1 /* sideeffect attdialect */
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:  bb.5.iftrue (bbsections Cold):
+  ; CHECK-NEXT:    successors: %bb.1(0x80000000)
+  ; CHECK-NEXT:    liveins: $x16
+  ; CHECK-NEXT:    {{ $}}
+  ; CHECK-NEXT:    $[[SCAVENGED_REGISTER:x[0-9]+]] = ADRP target-flags(aarch64-page) <mcsymbol .LBB1_1>
+  ; CHECK-NEXT:    $[[SCAVENGED_REGISTER]] = ADDXri $[[SCAVENGED_REGISTER]], target-flags(aarch64-pageoff, aarch64-nc) <mcsymbol .LBB1_1>, 0
+  ; CHECK-NEXT:    BR $[[SCAVENGED_REGISTER]]
+
+  bb.0.entry:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+  
+    $sp = frame-setup SUBXri $sp, 16, 0
+    INLINEASM &"mov x16, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x16
+    dead renamable $x8 = SUBSXri $x16, 0, 0, implicit-def $nzcv
+    renamable $w8 = CSINCWr $wzr, $wzr, 1, implicit killed $nzcv
+    TBZW killed renamable $w8, 0, %bb.1
+
+    B %bb.2
+  
+  bb.1.iffalse:
+    liveins: $x16
+    
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x16
+    $sp = frame-destroy ADDXri $sp, 16, 0
+    RET undef $lr
+
+  bb.2.iftrue (bbsections Cold):
+    successors: %bb.1(0x80000000)
+    liveins: $x16
+  
+    INLINEASM &".space 4", 1 /* sideeffect attdialect */
+    B %bb.1
+...
+---
+name:            all_used_cold_to_hot
+tracksRegLiveness: true
+frameInfo:
+  stackSize:       112
+  maxAlignment:    16
+stack:
+  - { id: 0, name: '', type: spill-slot, offset: -8, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x19', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, name: '', type: spill-slot, offset: -16, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x20', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 2, name: '', type: spill-slot, offset: -24, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x21', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 3, name: '', type: spill-slot, offset: -32, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x22', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 4, name: '', type: spill-slot, offset: -40, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x23', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 5, name: '', type: spill-slot, offset: -48, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x24', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 6, name: '', type: spill-slot, offset: -56, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x25', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 7, name: '', type: spill-slot, offset: -64, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x26', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 8, name: '', type: spill-slot, offset: -72, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x27', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 9, name: '', type: spill-slot, offset: -80, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '$x28', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 10, name: '', type: spill-slot, offset: -96, size: 8, alignment: 16, 
+      stack-id: default, callee-saved-register: '$fp', callee-saved-restored: true, 
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+machineFunctionInfo:
+  hasRedZone:      false
+body:             |
+  ; CHECK-LABEL: name: all_used_cold_to_hot
+  ; COM: Check that unconditional branches from the cold section to
+  ; COM: the hot section spill x16 and defer indirect branch
+  ; COM: insertion to the linker if there are no free general-purpose
+  ; COM: registers.
+  ; CHECK:      bb.0.entry:
+  ; CHECK-NEXT:     successors: %bb.3(0x80000000)
+  ; CHECK-NEXT:     liveins: $fp, $x27, $x28, $x25, $x26, $x23, $x24, $x21, $x22, $x19, $x20
+  ; CHECK-COUNT-29: INLINEASM &"mov
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK:      bb.3.entry:
+  ; CHECK-NEXT:     successors: %bb.2(0x80000000)
+  ; CHECK-NEXT:     liveins: $fp,  $x0,  $x1,  $x2,  $x3,  $x4,  $x5,  $x6,  $x7,  $x8,
+  ; CHECK-SAME:              $x9,  $x10, $x11, $x12, $x13, $x14, $x15, $x17, $x18, $x19,
+  ; CHECK-SAME:              $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:     B %bb.2
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:   bb.1.exit:
+  ; CHECK-NEXT:     liveins: $x0,  $x1,  $x2,  $x3,  $x4,  $x5,  $x6,  $x7,  $x8,  $x9,
+  ; CHECK-SAME:              $x10, $x11, $x12, $x13, $x14, $x15, $x16, $x17, $x18, $x19,
+  ; CHECK-SAME:              $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $fp
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-COUNT-30: INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed
+  ; CHECK:          RET undef $lr
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:   bb.6.exit:
+  ; CHECK-NEXT:     successors: %bb.7(0x80000000)
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:     early-clobber $sp, $x16 = LDRXpost $sp, 16
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:   bb.7.exit:
+  ; CHECK-NEXT:     successors: %bb.1(0x80000000)
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:     B %bb.1
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:   bb.2.cold (bbsections Cold):
+  ; CHECK-NEXT:     successors: %bb.5(0x80000000)
+  ; CHECK-NEXT:     liveins: $x0,  $x1,  $x2,  $x3,  $x4,  $x5,  $x6,  $x7,  $x8,  $x9,
+  ; CHECK-SAME:              $x10, $x11, $x12, $x13, $x14, $x15, $x17, $x18, $x19, $x20,
+  ; CHECK-SAME:              $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $fp
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:     INLINEASM &"mov x16, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x16
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:   bb.5.cold (bbsections Cold):
+  ; CHECK-NEXT:     successors: %bb.6(0x80000000)
+  ; CHECK-NEXT:     liveins: $fp,  $x0,  $x1,  $x2,  $x3,  $x4,  $x5,  $x6,  $x7,  $x8,
+  ; CHECK-SAME:              $x9,  $x10, $x11, $x12, $x13, $x14, $x15, $x16, $x17, $x18,
+  ; CHECK-SAME:              $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28
+  ; CHECK-NEXT:     {{ $}}
+  ; CHECK-NEXT:     early-clobber $sp = STRXpre $x16, $sp, -16
+  ; CHECK-NEXT:     B %bb.6
+
+  bb.0.entry:
+    successors: %bb.2(0x80000000)
+    liveins: $fp, $x27, $x28, $x25, $x26, $x23, $x24, $x21, $x22, $x19, $x20
+  
+    $sp = frame-setup SUBXri $sp, 112, 0
+    frame-setup STRXui killed $fp, $sp, 2 :: (store (s64) into %stack.10)
+    frame-setup STPXi killed $x28, killed $x27, $sp, 4 :: (store (s64) into %stack.9), (store (s64) into %stack.8)
+    frame-setup STPXi killed $x26, killed $x25, $sp, 6 :: (store (s64) into %stack.7), (store (s64) into %stack.6)
+    frame-setup STPXi killed $x24, killed $x23, $sp, 8 :: (store (s64) into %stack.5), (store (s64) into %stack.4)
+    frame-setup STPXi killed $x22, killed $x21, $sp, 10 :: (store (s64) into %stack.3), (store (s64) into %stack.2)
+    frame-setup STPXi killed $x20, killed $x19, $sp, 12 :: (store (s64) into %stack.1), (store (s64) into %stack.0)
+    INLINEASM &"mov x0, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x0
+    INLINEASM &"mov x1, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x1
+    INLINEASM &"mov x2, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x2
+    INLINEASM &"mov x3, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x3
+    INLINEASM &"mov x4, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x4
+    INLINEASM &"mov x5, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x5
+    INLINEASM &"mov x6, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x6
+    INLINEASM &"mov x7, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x7
+    INLINEASM &"mov x8, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x8
+    INLINEASM &"mov x9, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x9
+    INLINEASM &"mov x10, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x10
+    INLINEASM &"mov x11, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x11
+    INLINEASM &"mov x12, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x12
+    INLINEASM &"mov x13, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x13
+    INLINEASM &"mov x14, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x14
+    INLINEASM &"mov x15, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x15
+    INLINEASM &"mov x17, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x17
+    INLINEASM &"mov x18, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x18
+    INLINEASM &"mov x19, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x19
+    INLINEASM &"mov x20, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x20
+    INLINEASM &"mov x21, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x21
+    INLINEASM &"mov x22, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x22
+    INLINEASM &"mov x23, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x23
+    INLINEASM &"mov x24, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x24
+    INLINEASM &"mov x25, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x25
+    INLINEASM &"mov x26, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x26
+    INLINEASM &"mov x27, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x27
+    INLINEASM &"mov x28, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x28
+    INLINEASM &"mov fp, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $fp
+    B %bb.2
+  
+
+  bb.1.exit:
+    liveins: $x0, $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15, $x16, $x17, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $fp
+
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x0
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x1
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x2
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x3
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x4
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x5
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x6
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x7
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x8
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x9
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x10
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x11
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x12
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x13
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x14
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x15
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x16
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x17
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x18
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x19
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x20
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x21
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x22
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x23
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x24
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x25
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x26
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x27
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $x28
+    INLINEASM &"# reg use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, killed $fp
+    $x20, $x19 = frame-destroy LDPXi $sp, 12 :: (load (s64) from %stack.1), (load (s64) from %stack.0)
+    $x22, $x21 = frame-destroy LDPXi $sp, 10 :: (load (s64) from %stack.3), (load (s64) from %stack.2)
+    $x24, $x23 = frame-destroy LDPXi $sp, 8 :: (load (s64) from %stack.5), (load (s64) from %stack.4)
+    $x26, $x25 = frame-destroy LDPXi $sp, 6 :: (load (s64) from %stack.7), (load (s64) from %stack.6)
+    $x28, $x27 = frame-destroy LDPXi $sp, 4 :: (load (s64) from %stack.9), (load (s64) from %stack.8)
+    $fp = frame-destroy LDRXui $sp, 2 :: (load (s64) from %stack.10)
+    $sp = frame-destroy ADDXri $sp, 112, 0
+    RET undef $lr
+  
+  bb.2.cold (bbsections Cold):
+    successors: %bb.1(0x80000000)
+    liveins: $x0, $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15, $x17, $x18, $x19, $x20, $x21, $x22, $x23, $x24, $x25, $x26, $x27, $x28, $fp
+
+    INLINEASM &"mov x16, 1", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $x16
+    B %bb.1
+
+...