diff --git a/llvm/test/Transforms/InstCombine/add.ll b/llvm/test/Transforms/InstCombine/add.ll
index d84be9cd29d46..73e21d4370b7e 100644
--- a/llvm/test/Transforms/InstCombine/add.ll
+++ b/llvm/test/Transforms/InstCombine/add.ll
@@ -1,6 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
+declare void @use(i8)
+declare void @use_i1(i1)
+
 define i32 @select_0_or_1_from_bool(i1 %x) {
 ; CHECK-LABEL: @select_0_or_1_from_bool(
 ; CHECK-NEXT:    [[NOT_X:%.*]] = xor i1 [[X:%.*]], true
@@ -280,8 +283,6 @@ define i8 @reassoc_shl1_commute3(i8 %px, i8 %py) {
   ret i8 %r
 }
 
-declare void @use(i8)
-
 define i8 @reassoc_shl1_extra_use(i8 %x, i8 %y) {
 ; CHECK-LABEL: @reassoc_shl1_extra_use(
 ; CHECK-NEXT:    [[A:%.*]] = add i8 [[Y:%.*]], [[X:%.*]]
@@ -2729,3 +2730,129 @@ define i32 @floor_sdiv_wrong_op(i32 %x, i32 %y) {
   %r = add i32 %d, %s
   ret i32 %r
 }
+
+define i8 @signum_i8_i8(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  %zgt0 = zext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 7
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define i8 @signum_i8_i8_use1(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_use1(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    call void @use(i8 [[SIGNBIT]])
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  %zgt0 = zext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 7
+  call void @use(i8 %signbit)
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define i8 @signum_i8_i8_use2(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_use2(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    call void @use(i8 [[ZGT0]])
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  %zgt0 = zext i1 %sgt0 to i8
+  call void @use(i8 %zgt0)
+  %signbit = ashr i8 %x, 7
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define i8 @signum_i8_i8_use3(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_use3(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    call void @use_i1(i1 [[SGT0]])
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  call void @use_i1(i1 %sgt0)
+  %zgt0 = zext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 7
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define <2 x i5> @signum_v2i5_v2i5(<2 x i5> %x) {
+; CHECK-LABEL: @signum_v2i5_v2i5(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt <2 x i5> [[X:%.*]], zeroinitializer
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext <2 x i1> [[SGT0]] to <2 x i5>
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr <2 x i5> [[X]], <i5 4, i5 poison>
+; CHECK-NEXT:    [[R:%.*]] = add <2 x i5> [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret <2 x i5> [[R]]
+;
+  %sgt0 = icmp sgt <2 x i5> %x, zeroinitializer
+  %zgt0 = zext <2 x i1> %sgt0 to <2 x i5>
+  %signbit = ashr <2 x i5> %x, <i5 4, i5 poison>
+  %r = add <2 x i5> %signbit, %zgt0
+  ret <2 x i5> %r
+}
+
+define i8 @signum_i8_i8_wrong_sh_amt(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_wrong_sh_amt(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 6
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  %zgt0 = zext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 6
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define i8 @signum_i8_i8_wrong_ext(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_wrong_ext(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[ZGT0:%.*]] = sext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sgt i8 %x, 0
+  %zgt0 = sext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 7
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}
+
+define i8 @signum_i8_i8_wrong_pred(i8 %x) {
+; CHECK-LABEL: @signum_i8_i8_wrong_pred(
+; CHECK-NEXT:    [[SGT0:%.*]] = icmp sgt i8 [[X:%.*]], -1
+; CHECK-NEXT:    [[ZGT0:%.*]] = zext i1 [[SGT0]] to i8
+; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = add nsw i8 [[SIGNBIT]], [[ZGT0]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %sgt0 = icmp sge i8 %x, 0
+  %zgt0 = zext i1 %sgt0 to i8
+  %signbit = ashr i8 %x, 7
+  %r = add i8 %zgt0, %signbit
+  ret i8 %r
+}