1; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
2; RUN: llc < %s -O2 -mtriple=x86_64-unknown-unknown | FileCheck %s
3; Checks that a zeroing mov is inserted for the trunc/zext pair even when
4; the source of the zext is an AssertZext node
5; PR28540
6
7define i64 @foo() {
8; CHECK-LABEL: foo:
9; CHECK:       # %bb.0:
10; CHECK-NEXT:    movq $-1, %rax
11; CHECK-NEXT:    retq
12  ret i64 -1
13}
14
15define i64 @main() {
16; CHECK-LABEL: main:
17; CHECK:       # %bb.0:
18; CHECK-NEXT:    pushq %rax
19; CHECK-NEXT:    .cfi_def_cfa_offset 16
20; CHECK-NEXT:    callq foo
21; CHECK-NEXT:    movabsq $-4294967041, %rcx # imm = 0xFFFFFFFF000000FF
22; CHECK-NEXT:    andq %rax, %rcx
23; CHECK-NEXT:    movl %ecx, %ecx
24; CHECK-NEXT:    leaq (,%rcx,8), %rax
25; CHECK-NEXT:    subq %rcx, %rax
26; CHECK-NEXT:    shrq $32, %rax
27; CHECK-NEXT:    popq %rcx
28; CHECK-NEXT:    .cfi_def_cfa_offset 8
29; CHECK-NEXT:    retq
30  %b = call i64 @foo()
31  %or = and i64 %b, 18446744069414584575 ; this is 0xffffffff000000ff
32  %trunc = trunc i64 %or to i32
33  br label %l
34l:
35  %ext = zext i32 %trunc to i64
36  %mul = mul i64 %ext, 7
37  br label %m
38m: ; keeps dag combine from seeing the multiply and the shift together
39  %shr = lshr i64 %mul, 32
40  trunc i64 %or to i32 ; keeps the and alive so it doesn't simplify
41  ret i64 %shr
42}
43