xref: /llvm-project/llvm/test/Transforms/InstCombine/idioms.ll (revision d77067d08a3f56dc2d0e6c95bd2852c943df743a)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
2; RUN: opt -passes=instcombine -S < %s | FileCheck %s
3; RUN: opt -passes=instcombine,simplifycfg,instcombine -S < %s | FileCheck %s --check-prefix=EXTRA-PASSES
4
5; Check that code corresponding to the following C function is
6; simplified into a single ASR operation:
7;
8; int test_asr(int a, int b) {
9;   return a < 0 ? -(-a - 1 >> b) - 1 : a >> b;
10; }
11;
12
13define i32 @test_asr(i32 %a, i32 %b) {
14; CHECK-LABEL: define i32 @test_asr(
15; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
16; CHECK-NEXT:  entry:
17; CHECK-NEXT:    [[C:%.*]] = icmp slt i32 [[A]], 0
18; CHECK-NEXT:    br i1 [[C]], label [[BB2:%.*]], label [[BB3:%.*]]
19; CHECK:       bb2:
20; CHECK-NEXT:    [[NOT2:%.*]] = ashr i32 [[A]], [[B]]
21; CHECK-NEXT:    br label [[BB4:%.*]]
22; CHECK:       bb3:
23; CHECK-NEXT:    [[E:%.*]] = lshr i32 [[A]], [[B]]
24; CHECK-NEXT:    br label [[BB4]]
25; CHECK:       bb4:
26; CHECK-NEXT:    [[F:%.*]] = phi i32 [ [[NOT2]], [[BB2]] ], [ [[E]], [[BB3]] ]
27; CHECK-NEXT:    ret i32 [[F]]
28;
29; EXTRA-PASSES-LABEL: define i32 @test_asr(
30; EXTRA-PASSES-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
31; EXTRA-PASSES-NEXT:  entry:
32; EXTRA-PASSES-NEXT:    [[C1:%.*]] = ashr i32 [[A]], [[B]]
33; EXTRA-PASSES-NEXT:    ret i32 [[C1]]
34;
35entry:
36  %c = icmp slt i32 %a, 0
37  br i1 %c, label %bb2, label %bb3
38
39bb2:
40  %t1 = sub i32 0, %a
41  %not = sub i32 %t1, 1
42  %d = ashr i32 %not, %b
43  %t2 = sub i32 0, %d
44  %not2 = sub i32 %t2, 1
45  br label %bb4
46bb3:
47  %e = ashr i32 %a, %b
48  br label %bb4
49bb4:
50  %f = phi i32 [ %not2, %bb2 ], [ %e, %bb3 ]
51  ret i32 %f
52}
53