Index: llvm/lib/CodeGen/LiveRangeEdit.cpp
===================================================================
--- llvm/lib/CodeGen/LiveRangeEdit.cpp
+++ llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -107,7 +107,7 @@
                                        SlotIndex OrigIdx,
                                        SlotIndex UseIdx) const {
   OrigIdx = OrigIdx.getRegSlot(true);
-  UseIdx = UseIdx.getRegSlot(true);
+  UseIdx = std::max(UseIdx, UseIdx.getRegSlot(true));
   for (unsigned i = 0, e = OrigMI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = OrigMI->getOperand(i);
     if (!MO.isReg() || !MO.getReg() || !MO.readsReg())
Index: llvm/test/CodeGen/AArch64/pr51516.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/pr51516.mir
@@ -0,0 +1,208 @@
+# RUN: llc -mtriple=aarch64-unknown-fuchsia -run-pass=greedy -verify-machineinstrs -o - %s | FileCheck %s
+
+# Check that we spill %31 and do not rematerialize it since the use operand
+# of ADDXri is killed by the STRXui in this block.
+
+# CHECK-LABEL: name: test
+# CHECK: bb.17:
+# CHECK:   STRXui
+# CHECK:   LDRXui
+# CHECK: bb.18:
+
+---
+name:            test
+tracksRegLiveness: true
+stack:
+  - { id: 0, type: variable-sized, offset: 0, alignment: 32,
+      stack-id: default }
+body:             |
+  bb.0.entry:
+    successors: %bb.2(0x40000000), %bb.1(0x40000000)
+    liveins: $x0
+
+    %22:gpr64common = COPY $x0
+    CBZW $wzr, %bb.2
+
+  bb.1:
+    successors: %bb.3(0x80000000)
+
+    %1:gpr64 = COPY $xzr
+    B %bb.3
+
+  bb.2:
+    successors: %bb.3(0x80000000)
+
+    $x0 = IMPLICIT_DEF
+    %1:gpr64 = COPY $x0
+
+  bb.3:
+    successors: %bb.4(0x30000000), %bb.5(0x50000000)
+
+    %2:gpr64common = COPY %1
+    CBNZX %1, %bb.5
+    B %bb.4
+
+  bb.4:
+    successors: %bb.5(0x80000000)
+
+    %31:gpr64common = SUBXri $sp, 288, 0
+    $sp = ANDXri %31, 7930
+    %2:gpr64common = COPY $xzr
+
+  bb.5:
+    successors: %bb.6(0x80000000)
+
+    %9:gpr64common = COPY $xzr
+    %35:gpr64sp = ADDXri %2, 32, 0
+    %4:gpr64common = UBFMXri %2, 3, 63
+    %37:gpr64 = MOVi64imm -506381209866536712
+    %38:gpr32 = MOVi32imm -202116109
+    %39:gpr64common = nuw ADDXri %22, 836, 0
+    %41:gpr64common = nuw ADDXri %22, 648, 0
+    STRXui %37, %4, 1
+    STRWui %38, %4, 8
+    %8:gpr64common = UBFMXri %39, 3, 63
+    %7:gpr64common = UBFMXri %41, 3, 63
+    %47:gpr64 = MOVi64imm 0
+
+  bb.6:
+    successors: %bb.8(0x30000000), %bb.7(0x50000000)
+
+    %44:gpr64common = ADDXrr %22, %9
+    %10:gpr64common = ADDXri %44, 648, 0
+    %11:gpr64common = ANDSXri %10, 4098, implicit-def $nzcv
+    Bcc 0, %bb.8, implicit killed $nzcv
+    B %bb.7
+
+  bb.7:
+    successors: %bb.8(0x80000000)
+
+    BL 0, csr_aarch64_aapcs, implicit-def dead $lr
+
+  bb.8:
+    successors: %bb.9(0x04000000), %bb.24(0x7c000000)
+
+    CBNZW $wzr, %bb.24
+    B %bb.9
+
+  bb.9:
+    successors: %bb.10(0x7ffff800), %bb.11(0x00000800)
+
+    %55:gpr64common = ADDXrr %22, %9
+    %56:gpr64sp = ADDXri %55, 648, 0
+    CBZX %11, %bb.10
+    B %bb.11
+
+  bb.10:
+    successors: %bb.11(0x80000000)
+
+    $x0 = ADDXri %55, 648, 0
+    $x2 = IMPLICIT_DEF
+    $w1 = COPY $wzr
+    $x1 = nuw ADDXri %35, 32, 0
+    BL 0, csr_aarch64_aapcs, implicit-def dead $lr
+    %66:gpr64sp = nuw ADDXri %35, 48, 0
+    $x0 = ADDXri %55, 696, 0
+    $x2 = IMPLICIT_DEF
+    $x1 = COPY %66
+
+  bb.11:
+    successors: %bb.15(0x7ffff800), %bb.12(0x00000800)
+
+    CBZX %11, %bb.15
+    B %bb.12
+
+  bb.12:
+    successors: %bb.13(0x00000000), %bb.14(0x80000000)
+
+    CBNZW $wzr, %bb.14
+    B %bb.13
+
+  bb.13:
+    successors:
+
+  bb.14:
+    successors: %bb.18(0x80000000)
+
+    $x1 = COPY %56
+    B %bb.18
+
+  bb.15:
+    successors: %bb.16(0x00000000), %bb.17(0x80000000)
+
+    %76:gpr32 = LDRBBui %7, 0
+    CBZW %76, %bb.17
+    B %bb.16
+
+  bb.16:
+    successors:
+
+    %74:gpr64common = ADDXrr %22, %9
+    %15:gpr64sp = ADDXri %74, 648, 0
+    $x0 = COPY %15
+
+  bb.17:
+    successors: %bb.18(0x80000000)
+
+    STRXui %22, %55, 81
+
+  bb.18:
+    successors: %bb.19(0x80000000), %bb.20(0x00000000)
+
+    %79:gpr32 = LDRBBui %8, 0
+    CBNZW %79, %bb.20
+    B %bb.19
+
+  bb.19:
+    successors: %bb.21(0x80000000), %bb.20(0x00000000)
+
+    %80:gpr32 = MOVi32imm 1
+    CBNZW %80, %bb.21
+    B %bb.20
+
+  bb.20:
+    successors:
+
+    %16:gpr64sp = ADDXri %22, 836, 0
+    $x0 = COPY %16
+
+  bb.21:
+    successors: %bb.24(0x00000000), %bb.22(0x80000000)
+
+    CBZW $wzr, %bb.24
+
+  bb.22:
+    successors: %bb.26(0x80000000)
+
+    B %bb.26
+
+  bb.24:
+    successors: %bb.25(0x04000000), %bb.6(0x7c000000)
+
+    %8:gpr64common = ADDXri %8, 24, 0
+    %7:gpr64common = ADDXri %7, 24, 0
+    CBNZW $wzr, %bb.6
+
+  bb.25:
+    successors: %bb.26(0x80000000)
+
+    %56:gpr64sp = COPY $xzr
+
+  bb.26:
+    successors: %bb.28(0x50000000), %bb.27(0x30000000)
+
+    undef %83.sub_32:gpr64 = MOVi32imm 1172321806
+    STRXui %83, %2, 0
+    CBNZX %1, %bb.28
+    B %bb.27
+
+  bb.27:
+    successors: %bb.28(0x80000000)
+
+    STRXui $xzr, %4, 0
+
+  bb.28:
+    $x0 = COPY %56
+    RET_ReallyLR implicit $x0
+
+...
Index: llvm/test/CodeGen/AMDGPU/pr51516.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/pr51516.mir
@@ -0,0 +1,114 @@
+# RUN: llc -mtriple=amdgcn--amdhsa -mcpu=gfx900 -verify-machineinstrs -start-before=machine-scheduler -stop-after=virtregrewriter,1 -o - %s | FileCheck -check-prefix=GCN %s
+
+# Check that %3 was not rematerialized before the last store since its operand %1
+# is killed by that store.
+
+# GCN-LABEL: name: global_sextload_v32i32_to_v32i64
+# GCN: renamable $vgpr0 = SI_SPILL_V32_RESTORE %stack.0, $sgpr32, 0, implicit $exec :: (load (s32) from %stack.0, addrspace 5)
+# GCN: GLOBAL_STORE_DWORDX4_SADDR killed renamable $vgpr27, killed renamable $vgpr19_vgpr20_vgpr21_vgpr22, killed renamable $sgpr0_sgpr1, 16, 0, implicit $exec, implicit killed renamable $vgpr0
+
+---
+name:            global_sextload_v32i32_to_v32i64
+tracksRegLiveness: true
+machineFunctionInfo:
+  scratchRSrcReg:  '$sgpr96_sgpr97_sgpr98_sgpr99'
+  stackPtrOffsetReg: '$sgpr32'
+body:             |
+  bb.0:
+    liveins: $sgpr4_sgpr5
+
+    %0:sgpr_64(p4) = COPY $sgpr4_sgpr5
+    %1:vgpr_32 = COPY $m0
+    %2:sgpr_128 = S_LOAD_DWORDX4_IMM %0(p4), 0, 0
+    %3:vgpr_32 = V_MOV_B32_e32 %1, implicit $exec
+    %4:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 112, 0, implicit $exec :: (load (s128))
+    %5:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 96, 0, implicit $exec, implicit %1 :: (load (s128))
+    %6:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 80, 0, implicit $exec :: (load (s128))
+    %7:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 64, 0, implicit $exec :: (load (s128))
+    %8:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 48, 0, implicit $exec :: (load (s128))
+    %9:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 32, 0, implicit $exec :: (load (s128))
+    %10:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 16, 0, implicit $exec :: (load (s128))
+    %11:vreg_128 = GLOBAL_LOAD_DWORDX4_SADDR %2.sub2_sub3, %3, 0, 0, implicit $exec :: (load (s128))
+    undef %12.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %11.sub3, implicit $exec
+    %12.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %11.sub2, implicit $exec
+    undef %13.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %11.sub1, implicit $exec
+    %13.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %11.sub0, implicit $exec
+    undef %14.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %10.sub3, implicit $exec
+    %14.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %10.sub2, implicit $exec
+    undef %15.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %10.sub1, implicit $exec
+    %15.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %10.sub0, implicit $exec
+    undef %16.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %9.sub3, implicit $exec
+    %16.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %9.sub2, implicit $exec
+    undef %17.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %9.sub1, implicit $exec
+    %17.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %9.sub0, implicit $exec
+    undef %18.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %8.sub3, implicit $exec
+    %18.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %8.sub2, implicit $exec
+    undef %19.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %8.sub1, implicit $exec
+    %19.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %8.sub0, implicit $exec
+    undef %20.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %7.sub3, implicit $exec
+    %20.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %7.sub2, implicit $exec
+    undef %21.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %7.sub1, implicit $exec
+    %21.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %7.sub0, implicit $exec
+    undef %22.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %6.sub3, implicit $exec
+    %22.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %6.sub2, implicit $exec
+    undef %23.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %6.sub1, implicit $exec
+    %23.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %6.sub0, implicit $exec
+    undef %24.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %5.sub3, implicit $exec
+    %24.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %5.sub2, implicit $exec
+    undef %25.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %5.sub1, implicit $exec
+    %25.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %5.sub0, implicit $exec
+    undef %26.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %4.sub3, implicit $exec
+    %26.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %4.sub2, implicit $exec
+    undef %27.sub3:vreg_128 = V_ASHRREV_I32_e32 31, %4.sub1, implicit $exec
+    %27.sub1:vreg_128 = V_ASHRREV_I32_e32 31, %4.sub0, implicit $exec
+    %27.sub0:vreg_128 = COPY %4.sub0
+    %27.sub2:vreg_128 = COPY %4.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %27, %2.sub0_sub1, 224, 0, implicit $exec
+    %26.sub0:vreg_128 = COPY %4.sub2
+    %26.sub2:vreg_128 = COPY %4.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %26, %2.sub0_sub1, 240, 0, implicit $exec
+    %25.sub0:vreg_128 = COPY %5.sub0
+    %25.sub2:vreg_128 = COPY %5.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %25, %2.sub0_sub1, 192, 0, implicit $exec
+    %24.sub0:vreg_128 = COPY %5.sub2
+    %24.sub2:vreg_128 = COPY %5.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %24, %2.sub0_sub1, 208, 0, implicit $exec
+    %23.sub0:vreg_128 = COPY %6.sub0
+    %23.sub2:vreg_128 = COPY %6.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %23, %2.sub0_sub1, 160, 0, implicit $exec
+    %22.sub0:vreg_128 = COPY %6.sub2
+    %22.sub2:vreg_128 = COPY %6.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %22, %2.sub0_sub1, 176, 0, implicit $exec
+    %21.sub0:vreg_128 = COPY %7.sub0
+    %21.sub2:vreg_128 = COPY %7.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %21, %2.sub0_sub1, 128, 0, implicit $exec
+    %20.sub0:vreg_128 = COPY %7.sub2
+    %20.sub2:vreg_128 = COPY %7.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %20, %2.sub0_sub1, 144, 0, implicit $exec
+    %19.sub0:vreg_128 = COPY %8.sub0
+    %19.sub2:vreg_128 = COPY %8.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %19, %2.sub0_sub1, 96, 0, implicit $exec
+    %18.sub0:vreg_128 = COPY %8.sub2
+    %18.sub2:vreg_128 = COPY %8.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %18, %2.sub0_sub1, 112, 0, implicit $exec
+    %17.sub0:vreg_128 = COPY %9.sub0
+    %17.sub2:vreg_128 = COPY %9.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %17, %2.sub0_sub1, 64, 0, implicit $exec
+    %16.sub0:vreg_128 = COPY %9.sub2
+    %16.sub2:vreg_128 = COPY %9.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %16, %2.sub0_sub1, 80, 0, implicit $exec
+    %15.sub0:vreg_128 = COPY %10.sub0
+    %15.sub2:vreg_128 = COPY %10.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %15, %2.sub0_sub1, 32, 0, implicit $exec
+    %14.sub0:vreg_128 = COPY %10.sub2
+    %14.sub2:vreg_128 = COPY %10.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %14, %2.sub0_sub1, 48, 0, implicit $exec
+    %13.sub0:vreg_128 = COPY %11.sub0
+    %13.sub2:vreg_128 = COPY %11.sub1
+    GLOBAL_STORE_DWORDX4_SADDR %3, %13, %2.sub0_sub1, 0, 0, implicit $exec
+    %12.sub0:vreg_128 = COPY %11.sub2
+    %12.sub2:vreg_128 = COPY %11.sub3
+    GLOBAL_STORE_DWORDX4_SADDR %3, %12, %2.sub0_sub1, 16, 0, implicit $exec, implicit killed %1
+    S_ENDPGM 0
+
+...