xref: /llvm-project/llvm/test/Transforms/InstCombine/fls.ll (revision b8f3024a315074e0f880542c33cb89681eebc5a3)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt < %s -passes=instcombine -S | FileCheck %s
3
4target triple = "x86_64-unknown-freebsd11.0"
5
6define i32 @myfls() {
7; CHECK-LABEL: @myfls(
8; CHECK-NEXT:    ret i32 6
9;
10  %call = call i32 @fls(i32 42)
11  ret i32 %call
12}
13
14define i32 @myflsl() {
15; CHECK-LABEL: @myflsl(
16; CHECK-NEXT:    ret i32 6
17;
18  %patatino = call i32 @flsl(i64 42)
19  ret i32 %patatino
20}
21
22define i32 @myflsll() {
23; CHECK-LABEL: @myflsll(
24; CHECK-NEXT:    ret i32 6
25;
26  %whatever = call i32 @flsll(i64 42)
27  ret i32 %whatever
28}
29
30; Lower to llvm.ctlz() if the argument is not a constant
31
32define i32 @flsnotconst(i64 %z) {
33; CHECK-LABEL: @flsnotconst(
34; CHECK-NEXT:    [[CTLZ:%.*]] = call range(i64 0, 65) i64 @llvm.ctlz.i64(i64 [[Z:%.*]], i1 false)
35; CHECK-NEXT:    [[TMP1:%.*]] = trunc nuw nsw i64 [[CTLZ]] to i32
36; CHECK-NEXT:    [[GOO:%.*]] = sub nsw i32 64, [[TMP1]]
37; CHECK-NEXT:    ret i32 [[GOO]]
38;
39  %goo = call i32 @flsl(i64 %z)
40  ret i32 %goo
41}
42
43; Make sure we lower fls(0) to 0 and not to `undef`.
44
45define i32 @flszero() {
46; CHECK-LABEL: @flszero(
47; CHECK-NEXT:    ret i32 0
48;
49  %zero = call i32 @fls(i32 0)
50  ret i32 %zero
51}
52
53declare i32 @fls(i32)
54declare i32 @flsl(i64)
55declare i32 @flsll(i64)
56