xref: /llvm-project/llvm/test/Transforms/GVN/calloc-load-removal.ll (revision 23abf931386002fb9d2c11d026846475c224c641)
1; RUN: opt -S -passes=gvn < %s | FileCheck %s
2; Check that loads from calloc are recognized as being zero.
3
4target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
5
6; Function Attrs: nounwind uwtable
7define i32 @test1() {
8  %1 = tail call noalias ptr @calloc(i64 1, i64 4)
9  ; This load is trivially constant zero
10  %2 = load i32, ptr %1, align 4
11  ret i32 %2
12
13; CHECK-LABEL: @test1(
14; CHECK-NOT: %2 = load i32, ptr %1, align 4
15; CHECK: ret i32 0
16
17; CHECK_NO_LIBCALLS-LABEL: @test1(
18; CHECK_NO_LIBCALLS: load
19; CHECK_NO_LIBCALLS: ret i32 %
20
21}
22
23define i32 @as_invoke(i1 %c) personality ptr undef {
24bb3:
25  %mem = invoke noalias ptr @calloc(i64 1, i64 4)
26  to label %bb4 unwind label %bb1
27
28bb1:
29  %lp = landingpad { ptr, i32 } cleanup
30  ret i32 0
31
32bb4:
33  ; This load is trivially constant zero
34  %res = load i32, ptr %mem, align 4
35  ret i32 %res
36
37; CHECK-LABEL: @as_invoke(
38; CHECK-NOT: %3 = load i32, ptr %2, align 4
39; CHECK: ret i32 0
40
41; CHECK_NO_LIBCALLS-LABEL: @as_invoke(
42; CHECK_NO_LIBCALLS: load
43; CHECK_NO_LIBCALLS: ret i32 %
44}
45
46declare noalias ptr @calloc(i64, i64) allockind("alloc,zeroed") allocsize(0,1)
47