Index: llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -724,6 +724,10 @@
                   {v4s16, v4s16},
                   {v8s16, v8s16}});
 
+  // TODO: Vector types.
+  getActionDefinitionsBuilder({G_SADDSAT, G_SSUBSAT})
+      .lowerIf(isScalar(0));
+
   getLegacyLegalizerInfo().computeTables();
   verify(*ST.getInstrInfo());
 }
Index: llvm/test/CodeGen/AArch64/GlobalISel/legalize-saddsat.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/GlobalISel/legalize-saddsat.mir
@@ -0,0 +1,301 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=aarch64 -run-pass=legalizer -verify-machineinstrs -global-isel-abort=0 %s -o - | FileCheck %s
+
+...
+---
+name:            s32
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1
+    ; CHECK-LABEL: name: s32
+    ; CHECK: liveins: $w0, $w1
+    ; CHECK: %x:_(s32) = COPY $w0
+    ; CHECK: %y:_(s32) = COPY $w1
+    ; CHECK: [[SADDO:%[0-9]+]]:_(s32), [[SADDO1:%[0-9]+]]:_(s1) = G_SADDO %x, %y
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 31
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SADDO]], [[C]](s64)
+    ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 -2147483648
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[ASHR]], [[C1]]
+    ; CHECK: %saddsat:_(s32) = G_SELECT [[SADDO1]](s1), [[ADD]], [[SADDO]]
+    ; CHECK: $w0 = COPY %saddsat(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %x:_(s32) = COPY $w0
+    %y:_(s32) = COPY $w1
+    %saddsat:_(s32) = G_SADDSAT %x, %y
+    $w0 = COPY %saddsat(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s64
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0, $x1
+    ; CHECK-LABEL: name: s64
+    ; CHECK: liveins: $x0, $x1
+    ; CHECK: %x:_(s64) = COPY $x0
+    ; CHECK: %y:_(s64) = COPY $x1
+    ; CHECK: [[SADDO:%[0-9]+]]:_(s64), [[SADDO1:%[0-9]+]]:_(s1) = G_SADDO %x, %y
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 63
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[SADDO]], [[C]](s64)
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 -9223372036854775808
+    ; CHECK: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[ASHR]], [[C1]]
+    ; CHECK: %saddsat:_(s64) = G_SELECT [[SADDO1]](s1), [[ADD]], [[SADDO]]
+    ; CHECK: $x0 = COPY %saddsat(s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %x:_(s64) = COPY $x0
+    %y:_(s64) = COPY $x1
+    %saddsat:_(s64) = G_SADDSAT %x, %y
+    $x0 = COPY %saddsat(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            s16
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s16
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 16
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 16
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 16
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[ADD]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s16) = G_CONSTANT i16 15
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 16
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 15
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 -32768
+    ; CHECK: [[ADD1:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD1]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s16) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s16) = G_TRUNC %copy_2(s32)
+    %saddsat:_(s16) = G_SADDSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %saddsat(s16)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s1
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s1
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 1
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 1
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 1
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[ADD]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 0
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 1
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[ADD1:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD1]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s1) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s1) = G_TRUNC %copy_2(s32)
+    %saddsat:_(s1) = G_SADDSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %saddsat(s1)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s3
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s3
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 3
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 3
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 3
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[ADD]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 2
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 3
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 2
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 4
+    ; CHECK: [[ADD1:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD1]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s3) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s3) = G_TRUNC %copy_2(s32)
+    %saddsat:_(s3) = G_SADDSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %saddsat(s3)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s36
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0, $x1
+
+    ; CHECK-LABEL: name: s36
+    ; CHECK: liveins: $x0, $x1
+    ; CHECK: %copy_1:_(s64) = COPY $x0
+    ; CHECK: %copy_2:_(s64) = COPY $x1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY %copy_1(s64)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY]], 36
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY %copy_2(s64)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY1]], 36
+    ; CHECK: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s64) = COPY [[ADD]](s64)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY2]], 36
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[ADD]](s64), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 35
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s64) = COPY [[ADD]](s64)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY3]], 36
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 68719476735
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s64) = COPY [[C]](s64)
+    ; CHECK: [[AND:%[0-9]+]]:_(s64) = G_AND [[COPY4]], [[C1]]
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[SEXT_INREG3]], [[AND]](s64)
+    ; CHECK: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 34359738368
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s64) = COPY [[ASHR]](s64)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s64) = COPY [[C2]](s64)
+    ; CHECK: [[ADD1:%[0-9]+]]:_(s64) = G_ADD [[COPY5]], [[COPY6]]
+    ; CHECK: [[COPY7:%[0-9]+]]:_(s64) = COPY [[ADD1]](s64)
+    ; CHECK: [[COPY8:%[0-9]+]]:_(s64) = COPY [[ADD]](s64)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[TRUNC]](s1), [[COPY7]], [[COPY8]]
+    ; CHECK: %ext:_(s64) = COPY [[SELECT]](s64)
+    ; CHECK: $x0 = COPY %ext(s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %copy_1:_(s64) = COPY $x0
+    %x:_(s36) = G_TRUNC %copy_1(s64)
+    %copy_2:_(s64) = COPY $x1
+    %y:_(s36) = G_TRUNC %copy_2(s64)
+    %saddsat:_(s36) = G_SADDSAT %x, %y
+    %ext:_(s64) = G_ANYEXT %saddsat(s36)
+    $x0 = COPY %ext(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            s88
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x0
+    ; CHECK-LABEL: name: s88
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: %copy_1:_(s128) = COPY $q0
+    ; CHECK: %copy_2:_(s128) = COPY $q1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s128) = COPY %copy_1(s128)
+    ; CHECK: [[EXTRACT:%[0-9]+]]:_(s64) = G_EXTRACT [[COPY]](s128), 0
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 64
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK: [[UV:%[0-9]+]]:_(s64), [[UV1:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY]](s128)
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s128) = COPY %copy_2(s128)
+    ; CHECK: [[EXTRACT1:%[0-9]+]]:_(s64) = G_EXTRACT [[COPY1]](s128), 0
+    ; CHECK: [[UV2:%[0-9]+]]:_(s64), [[UV3:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY1]](s128)
+    ; CHECK: [[UADDO:%[0-9]+]]:_(s64), [[UADDO1:%[0-9]+]]:_(s1) = G_UADDO [[EXTRACT]], [[EXTRACT1]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[UV1]](s64)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC]], 24
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[UV3]](s64)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC1]], 24
+    ; CHECK: [[UADDE:%[0-9]+]]:_(s32), [[UADDE1:%[0-9]+]]:_(s1) = G_UADDE [[SEXT_INREG]], [[SEXT_INREG1]], [[UADDO1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[UADDE]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 24
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[UADDE]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[UV4:%[0-9]+]]:_(s8), [[UV5:%[0-9]+]]:_(s8), [[UV6:%[0-9]+]]:_(s8), [[UV7:%[0-9]+]]:_(s8), [[UV8:%[0-9]+]]:_(s8), [[UV9:%[0-9]+]]:_(s8), [[UV10:%[0-9]+]]:_(s8), [[UV11:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[UADDO]](s64)
+    ; CHECK: [[UV12:%[0-9]+]]:_(s8), [[UV13:%[0-9]+]]:_(s8), [[UV14:%[0-9]+]]:_(s8), [[UV15:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[UADDE]](s32)
+    ; CHECK: [[DEF:%[0-9]+]]:_(s8) = G_IMPLICIT_DEF
+    ; CHECK: [[DEF1:%[0-9]+]]:_(s32) = G_IMPLICIT_DEF
+    ; CHECK: [[UV16:%[0-9]+]]:_(s8), [[UV17:%[0-9]+]]:_(s8), [[UV18:%[0-9]+]]:_(s8), [[UV19:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[DEF1]](s32)
+    ; CHECK: [[UV20:%[0-9]+]]:_(s8), [[UV21:%[0-9]+]]:_(s8), [[UV22:%[0-9]+]]:_(s8), [[UV23:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[DEF1]](s32)
+    ; CHECK: [[MV:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV4]](s8), [[UV5]](s8), [[UV6]](s8), [[UV7]](s8)
+    ; CHECK: [[MV1:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV8]](s8), [[UV9]](s8), [[UV10]](s8), [[UV11]](s8)
+    ; CHECK: [[MV2:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV12]](s8), [[UV13]](s8), [[UV14]](s8), [[DEF]](s8)
+    ; CHECK: [[MV3:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV16]](s8), [[UV17]](s8), [[UV18]](s8), [[UV20]](s8)
+    ; CHECK: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 87
+    ; CHECK: [[C3:%[0-9]+]]:_(s64) = G_CONSTANT i64 40
+    ; CHECK: [[MV4:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV]](s32), [[MV1]](s32)
+    ; CHECK: [[MV5:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV2]](s32), [[MV3]](s32)
+    ; CHECK: [[SHL:%[0-9]+]]:_(s64) = G_SHL [[MV4]], [[C3]](s64)
+    ; CHECK: [[SHL1:%[0-9]+]]:_(s64) = G_SHL [[MV5]], [[C3]](s64)
+    ; CHECK: [[C4:%[0-9]+]]:_(s64) = G_CONSTANT i64 24
+    ; CHECK: [[LSHR:%[0-9]+]]:_(s64) = G_LSHR [[MV4]], [[C4]](s64)
+    ; CHECK: [[OR:%[0-9]+]]:_(s64) = G_OR [[SHL1]], [[LSHR]]
+    ; CHECK: [[LSHR1:%[0-9]+]]:_(s64) = G_LSHR [[SHL]], [[C3]](s64)
+    ; CHECK: [[SHL2:%[0-9]+]]:_(s64) = G_SHL [[OR]], [[C4]](s64)
+    ; CHECK: [[OR1:%[0-9]+]]:_(s64) = G_OR [[LSHR1]], [[SHL2]]
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[OR]], [[C3]](s64)
+    ; CHECK: [[C5:%[0-9]+]]:_(s64) = G_CONSTANT i64 23
+    ; CHECK: [[ASHR1:%[0-9]+]]:_(s64) = G_ASHR [[ASHR]], [[C5]](s64)
+    ; CHECK: [[C6:%[0-9]+]]:_(s64) = G_CONSTANT i64 63
+    ; CHECK: [[C7:%[0-9]+]]:_(s64) = G_CONSTANT i64 -8388608
+    ; CHECK: [[UADDO2:%[0-9]+]]:_(s64), [[UADDO3:%[0-9]+]]:_(s1) = G_UADDO [[ASHR1]], [[C1]]
+    ; CHECK: [[MV6:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV]](s32), [[MV1]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[TRUNC2]](s1), [[UADDO2]], [[MV6]]
+    ; CHECK: $x0 = COPY [[SELECT]](s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %copy_1:_(s128) = COPY $q0
+    %x:_(s88) = G_TRUNC %copy_1(s128)
+    %copy_2:_(s128) = COPY $q1
+    %y:_(s88) = G_TRUNC %copy_2(s128)
+    %saddsat:_(s88) = G_SADDSAT %x, %y
+    %trunc:_(s64) = G_TRUNC %saddsat(s88)
+    $x0 = COPY %trunc(s64)
+    RET_ReallyLR implicit $x0
Index: llvm/test/CodeGen/AArch64/GlobalISel/legalize-ssubsat.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/GlobalISel/legalize-ssubsat.mir
@@ -0,0 +1,301 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=aarch64 -run-pass=legalizer -verify-machineinstrs -global-isel-abort=0 %s -o - | FileCheck %s
+
+...
+---
+name:            s32
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1
+    ; CHECK-LABEL: name: s32
+    ; CHECK: liveins: $w0, $w1
+    ; CHECK: %x:_(s32) = COPY $w0
+    ; CHECK: %y:_(s32) = COPY $w1
+    ; CHECK: [[SSUBO:%[0-9]+]]:_(s32), [[SSUBO1:%[0-9]+]]:_(s1) = G_SSUBO %x, %y
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 31
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SSUBO]], [[C]](s64)
+    ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 -2147483648
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[ASHR]], [[C1]]
+    ; CHECK: %ssubsat:_(s32) = G_SELECT [[SSUBO1]](s1), [[ADD]], [[SSUBO]]
+    ; CHECK: $w0 = COPY %ssubsat(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %x:_(s32) = COPY $w0
+    %y:_(s32) = COPY $w1
+    %ssubsat:_(s32) = G_SSUBSAT %x, %y
+    $w0 = COPY %ssubsat(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s64
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0, $x1
+    ; CHECK-LABEL: name: s64
+    ; CHECK: liveins: $x0, $x1
+    ; CHECK: %x:_(s64) = COPY $x0
+    ; CHECK: %y:_(s64) = COPY $x1
+    ; CHECK: [[SSUBO:%[0-9]+]]:_(s64), [[SSUBO1:%[0-9]+]]:_(s1) = G_SSUBO %x, %y
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 63
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[SSUBO]], [[C]](s64)
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 -9223372036854775808
+    ; CHECK: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[ASHR]], [[C1]]
+    ; CHECK: %ssubsat:_(s64) = G_SELECT [[SSUBO1]](s1), [[ADD]], [[SSUBO]]
+    ; CHECK: $x0 = COPY %ssubsat(s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %x:_(s64) = COPY $x0
+    %y:_(s64) = COPY $x1
+    %ssubsat:_(s64) = G_SSUBSAT %x, %y
+    $x0 = COPY %ssubsat(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            s16
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s16
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 16
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 16
+    ; CHECK: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 16
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[SUB]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s16) = G_CONSTANT i16 15
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 16
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 15
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 -32768
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s16) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s16) = G_TRUNC %copy_2(s32)
+    %ssubsat:_(s16) = G_SSUBSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %ssubsat(s16)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s1
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s1
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 1
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 1
+    ; CHECK: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 1
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[SUB]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 0
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 1
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s1) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s1) = G_TRUNC %copy_2(s32)
+    %ssubsat:_(s1) = G_SSUBSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %ssubsat(s1)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s3
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $w0, $w1, $w2
+
+    ; CHECK-LABEL: name: s3
+    ; CHECK: liveins: $w0, $w1, $w2
+    ; CHECK: %copy_1:_(s32) = COPY $w0
+    ; CHECK: %copy_2:_(s32) = COPY $w1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY %copy_1(s32)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 3
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY %copy_2(s32)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY1]], 3
+    ; CHECK: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 3
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[SUB]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 2
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY3]], 3
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 2
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SEXT_INREG3]], [[C1]](s64)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ASHR]](s32)
+    ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 4
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[COPY4]], [[C2]]
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ADD]](s32)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[TRUNC]](s1), [[COPY5]], [[COPY6]]
+    ; CHECK: %ext:_(s32) = COPY [[SELECT]](s32)
+    ; CHECK: $w0 = COPY %ext(s32)
+    ; CHECK: RET_ReallyLR implicit $w0
+    %copy_1:_(s32) = COPY $w0
+    %x:_(s3) = G_TRUNC %copy_1(s32)
+    %copy_2:_(s32) = COPY $w1
+    %y:_(s3) = G_TRUNC %copy_2(s32)
+    %ssubsat:_(s3) = G_SSUBSAT %x, %y
+    %ext:_(s32) = G_ANYEXT %ssubsat(s3)
+    $w0 = COPY %ext(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            s36
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0, $x1
+
+    ; CHECK-LABEL: name: s36
+    ; CHECK: liveins: $x0, $x1
+    ; CHECK: %copy_1:_(s64) = COPY $x0
+    ; CHECK: %copy_2:_(s64) = COPY $x1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY %copy_1(s64)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY]], 36
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY %copy_2(s64)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY1]], 36
+    ; CHECK: [[SUB:%[0-9]+]]:_(s64) = G_SUB [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s64) = COPY [[SUB]](s64)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY2]], 36
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[SUB]](s64), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 35
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s64) = COPY [[SUB]](s64)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY3]], 36
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 68719476735
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s64) = COPY [[C]](s64)
+    ; CHECK: [[AND:%[0-9]+]]:_(s64) = G_AND [[COPY4]], [[C1]]
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[SEXT_INREG3]], [[AND]](s64)
+    ; CHECK: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 34359738368
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s64) = COPY [[ASHR]](s64)
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s64) = COPY [[C2]](s64)
+    ; CHECK: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[COPY5]], [[COPY6]]
+    ; CHECK: [[COPY7:%[0-9]+]]:_(s64) = COPY [[ADD]](s64)
+    ; CHECK: [[COPY8:%[0-9]+]]:_(s64) = COPY [[SUB]](s64)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[TRUNC]](s1), [[COPY7]], [[COPY8]]
+    ; CHECK: %ext:_(s64) = COPY [[SELECT]](s64)
+    ; CHECK: $x0 = COPY %ext(s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %copy_1:_(s64) = COPY $x0
+    %x:_(s36) = G_TRUNC %copy_1(s64)
+    %copy_2:_(s64) = COPY $x1
+    %y:_(s36) = G_TRUNC %copy_2(s64)
+    %ssubsat:_(s36) = G_SSUBSAT %x, %y
+    %ext:_(s64) = G_ANYEXT %ssubsat(s36)
+    $x0 = COPY %ext(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            s88
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $q0, $q1, $x0
+    ; CHECK-LABEL: name: s88
+    ; CHECK: liveins: $q0, $q1, $x0
+    ; CHECK: %copy_1:_(s128) = COPY $q0
+    ; CHECK: %copy_2:_(s128) = COPY $q1
+    ; CHECK: [[COPY:%[0-9]+]]:_(s128) = COPY %copy_1(s128)
+    ; CHECK: [[EXTRACT:%[0-9]+]]:_(s64) = G_EXTRACT [[COPY]](s128), 0
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 64
+    ; CHECK: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+    ; CHECK: [[UV:%[0-9]+]]:_(s64), [[UV1:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY]](s128)
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s128) = COPY %copy_2(s128)
+    ; CHECK: [[EXTRACT1:%[0-9]+]]:_(s64) = G_EXTRACT [[COPY1]](s128), 0
+    ; CHECK: [[UV2:%[0-9]+]]:_(s64), [[UV3:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY1]](s128)
+    ; CHECK: [[USUBO:%[0-9]+]]:_(s64), [[USUBO1:%[0-9]+]]:_(s1) = G_USUBO [[EXTRACT]], [[EXTRACT1]]
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[UV1]](s64)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC]], 24
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[UV3]](s64)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC1]], 24
+    ; CHECK: [[USUBE:%[0-9]+]]:_(s32), [[USUBE1:%[0-9]+]]:_(s1) = G_USUBE [[SEXT_INREG]], [[SEXT_INREG1]], [[USUBO1]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[USUBE]](s32)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY2]], 24
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[USUBE]](s32), [[SEXT_INREG2]]
+    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; CHECK: [[UV4:%[0-9]+]]:_(s8), [[UV5:%[0-9]+]]:_(s8), [[UV6:%[0-9]+]]:_(s8), [[UV7:%[0-9]+]]:_(s8), [[UV8:%[0-9]+]]:_(s8), [[UV9:%[0-9]+]]:_(s8), [[UV10:%[0-9]+]]:_(s8), [[UV11:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[USUBO]](s64)
+    ; CHECK: [[UV12:%[0-9]+]]:_(s8), [[UV13:%[0-9]+]]:_(s8), [[UV14:%[0-9]+]]:_(s8), [[UV15:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[USUBE]](s32)
+    ; CHECK: [[DEF:%[0-9]+]]:_(s8) = G_IMPLICIT_DEF
+    ; CHECK: [[DEF1:%[0-9]+]]:_(s32) = G_IMPLICIT_DEF
+    ; CHECK: [[UV16:%[0-9]+]]:_(s8), [[UV17:%[0-9]+]]:_(s8), [[UV18:%[0-9]+]]:_(s8), [[UV19:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[DEF1]](s32)
+    ; CHECK: [[UV20:%[0-9]+]]:_(s8), [[UV21:%[0-9]+]]:_(s8), [[UV22:%[0-9]+]]:_(s8), [[UV23:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[DEF1]](s32)
+    ; CHECK: [[MV:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV4]](s8), [[UV5]](s8), [[UV6]](s8), [[UV7]](s8)
+    ; CHECK: [[MV1:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV8]](s8), [[UV9]](s8), [[UV10]](s8), [[UV11]](s8)
+    ; CHECK: [[MV2:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV12]](s8), [[UV13]](s8), [[UV14]](s8), [[DEF]](s8)
+    ; CHECK: [[MV3:%[0-9]+]]:_(s32) = G_MERGE_VALUES [[UV16]](s8), [[UV17]](s8), [[UV18]](s8), [[UV20]](s8)
+    ; CHECK: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 87
+    ; CHECK: [[C3:%[0-9]+]]:_(s64) = G_CONSTANT i64 40
+    ; CHECK: [[MV4:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV]](s32), [[MV1]](s32)
+    ; CHECK: [[MV5:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV2]](s32), [[MV3]](s32)
+    ; CHECK: [[SHL:%[0-9]+]]:_(s64) = G_SHL [[MV4]], [[C3]](s64)
+    ; CHECK: [[SHL1:%[0-9]+]]:_(s64) = G_SHL [[MV5]], [[C3]](s64)
+    ; CHECK: [[C4:%[0-9]+]]:_(s64) = G_CONSTANT i64 24
+    ; CHECK: [[LSHR:%[0-9]+]]:_(s64) = G_LSHR [[MV4]], [[C4]](s64)
+    ; CHECK: [[OR:%[0-9]+]]:_(s64) = G_OR [[SHL1]], [[LSHR]]
+    ; CHECK: [[LSHR1:%[0-9]+]]:_(s64) = G_LSHR [[SHL]], [[C3]](s64)
+    ; CHECK: [[SHL2:%[0-9]+]]:_(s64) = G_SHL [[OR]], [[C4]](s64)
+    ; CHECK: [[OR1:%[0-9]+]]:_(s64) = G_OR [[LSHR1]], [[SHL2]]
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s64) = G_ASHR [[OR]], [[C3]](s64)
+    ; CHECK: [[C5:%[0-9]+]]:_(s64) = G_CONSTANT i64 23
+    ; CHECK: [[ASHR1:%[0-9]+]]:_(s64) = G_ASHR [[ASHR]], [[C5]](s64)
+    ; CHECK: [[C6:%[0-9]+]]:_(s64) = G_CONSTANT i64 63
+    ; CHECK: [[C7:%[0-9]+]]:_(s64) = G_CONSTANT i64 -8388608
+    ; CHECK: [[UADDO:%[0-9]+]]:_(s64), [[UADDO1:%[0-9]+]]:_(s1) = G_UADDO [[ASHR1]], [[C1]]
+    ; CHECK: [[MV6:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[MV]](s32), [[MV1]](s32)
+    ; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[TRUNC2]](s1), [[UADDO]], [[MV6]]
+    ; CHECK: $x0 = COPY [[SELECT]](s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %copy_1:_(s128) = COPY $q0
+    %x:_(s88) = G_TRUNC %copy_1(s128)
+    %copy_2:_(s128) = COPY $q1
+    %y:_(s88) = G_TRUNC %copy_2(s128)
+    %ssubsat:_(s88) = G_SSUBSAT %x, %y
+    %trunc:_(s64) = G_TRUNC %ssubsat(s88)
+    $x0 = COPY %trunc(s64)
+    RET_ReallyLR implicit $x0
Index: llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir
===================================================================
--- llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir
+++ llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir
@@ -357,15 +357,16 @@
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_SADDSAT (opcode {{[0-9]+}}): 1 type index, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_USUBSAT (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_SSUBSAT (opcode {{[0-9]+}}): 1 type index, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_USHLSAT (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined