xref: /llvm-project/llvm/test/Transforms/NewGVN/load-from-unreachable-predecessor.ll (revision 229640343e400394b315c6798c7c19e8a9bd188c)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
2; RUN: opt -passes=newgvn -S < %s | FileCheck %s
3
4; Check that an unreachable predecessor to a PHI node doesn't cause a crash.
5; PR21625.
6
7define i32 @f(ptr %f) {
8; CHECK-LABEL: define i32 @f(
9; CHECK-SAME: ptr [[F:%.*]]) {
10; CHECK-NEXT:  bb0:
11; CHECK-NEXT:    br label [[BB2:%.*]]
12; CHECK:       bb1:
13; CHECK-NEXT:    store i8 poison, ptr null, align 1
14; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB2]]
15; CHECK:       bb2:
16; CHECK-NEXT:    [[STOREMERGE:%.*]] = load i32, ptr null, align 4
17; CHECK-NEXT:    ret i32 [[STOREMERGE]]
18;
19; Load should be removed, since it's ignored.
20bb0:
21  %bar = load ptr, ptr %f
22  br label %bb2
23bb1:
24  %zed = load ptr, ptr %f
25  br i1 false, label %bb1, label %bb2
26bb2:
27  %foo = phi ptr [ null, %bb0 ], [ %zed, %bb1 ]
28  %storemerge = load i32, ptr %foo
29  ret i32 %storemerge
30}
31