Index: llvm/test/Transforms/SCCP/and-add-shl.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SCCP/and-add-shl.ll
@@ -0,0 +1,97 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt < %s -passes=ipsccp -S | FileCheck %s
+
+declare void @llvm.assume(i1)
+declare i8 @llvm.ctpop.i8(i8)
+
+; https://alive2.llvm.org/ce/z/LV_8xy
+define i8 @and_add_shl(i8 %x) {
+; CHECK-LABEL: define i8 @and_add_shl
+; CHECK-SAME: (i8 [[X:%.*]]) {
+; CHECK-NEXT:    [[OP1_P2:%.*]] = icmp ule i8 [[X]], 5
+; CHECK-NEXT:    call void @llvm.assume(i1 [[OP1_P2]])
+; CHECK-NEXT:    [[SHIFT:%.*]] = shl nuw nsw i8 1, [[X]]
+; CHECK-NEXT:    [[SUB:%.*]] = add nsw i8 [[SHIFT]], -1
+; CHECK-NEXT:    ret i8 0
+;
+  %op1_p2 = icmp ule i8 %x, 5
+  call void @llvm.assume(i1 %op1_p2)
+  %shift = shl i8 1, %x
+  %sub = add i8 %shift, -1
+  %r = and i8 %sub, 32
+  ret i8 %r
+}
+
+; https://alive2.llvm.org/ce/z/YNYYdV
+define i8 @and_not_shl(i8 %x) {
+; CHECK-LABEL: define i8 @and_not_shl
+; CHECK-SAME: (i8 [[X:%.*]]) {
+; CHECK-NEXT:    [[OP1_P2:%.*]] = icmp ule i8 [[X]], 5
+; CHECK-NEXT:    call void @llvm.assume(i1 [[OP1_P2]])
+; CHECK-NEXT:    [[SHIFT:%.*]] = shl nsw i8 -1, [[X]]
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[SHIFT]], -1
+; CHECK-NEXT:    [[R:%.*]] = and i8 [[NOT]], 32
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %op1_p2 = icmp ule i8 %x, 5
+  call void @llvm.assume(i1 %op1_p2)
+  %shift = shl i8 -1, %x
+  %not = xor i8 %shift, -1
+  %r = and i8 %not, 32
+  ret i8 %r
+}
+
+define i8 @and_not_shl_1(i8 %x) {
+; CHECK-LABEL: define i8 @and_not_shl_1
+; CHECK-SAME: (i8 [[X:%.*]]) {
+; CHECK-NEXT:    [[OP1_P2:%.*]] = icmp ule i8 [[X]], 4
+; CHECK-NEXT:    call void @llvm.assume(i1 [[OP1_P2]])
+; CHECK-NEXT:    [[SHIFT:%.*]] = shl nsw i8 -1, [[X]]
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[SHIFT]], -1
+; CHECK-NEXT:    [[R:%.*]] = and i8 [[NOT]], 48
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %op1_p2 = icmp ule i8 %x, 4
+  call void @llvm.assume(i1 %op1_p2)
+  %shift = shl i8 -1, %x
+  %not = xor i8 %shift, -1
+  %r = and i8 %not, 48 ;    3 * 16
+  ret i8 %r
+}
+
+; Negative test: https://alive2.llvm.org/ce/z/Zv4Pyu
+define i8 @and_add_shl_overlap(i8 %x) {
+; CHECK-LABEL: define i8 @and_add_shl_overlap
+; CHECK-SAME: (i8 [[X:%.*]]) {
+; CHECK-NEXT:    [[OP1_P2:%.*]] = icmp ule i8 [[X]], 6
+; CHECK-NEXT:    call void @llvm.assume(i1 [[OP1_P2]])
+; CHECK-NEXT:    [[SHIFT:%.*]] = shl nuw nsw i8 1, [[X]]
+; CHECK-NEXT:    [[SUB:%.*]] = add nsw i8 [[SHIFT]], -1
+; CHECK-NEXT:    [[R:%.*]] = and i8 [[SUB]], 32
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %op1_p2 = icmp ule i8 %x, 6
+  call void @llvm.assume(i1 %op1_p2)
+  %shift = shl i8 1, %x
+  %sub = add i8 %shift, -1
+  %r = and i8 %sub, 32  ; expect 64
+  ret i8 %r
+}
+
+define i8 @and_not_shl_overlap(i8 %x) {
+; CHECK-LABEL: define i8 @and_not_shl_overlap
+; CHECK-SAME: (i8 [[X:%.*]]) {
+; CHECK-NEXT:    [[OP1_P2:%.*]] = icmp ule i8 [[X]], 3
+; CHECK-NEXT:    call void @llvm.assume(i1 [[OP1_P2]])
+; CHECK-NEXT:    [[SHIFT:%.*]] = shl nsw i8 -1, [[X]]
+; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[SHIFT]], -1
+; CHECK-NEXT:    [[R:%.*]] = and i8 [[NOT]], 4
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %op1_p2 = icmp ule i8 %x, 3
+  call void @llvm.assume(i1 %op1_p2)
+  %shift = shl i8 -1, %x
+  %not = xor i8 %shift, -1
+  %r = and i8 %not, 4   ; expect 8
+  ret i8 %r
+}