xref: /llvm-project/llvm/test/CodeGen/Generic/undef-phi.ll (revision 0e8bd5a44a1bd8034706189b49a7a816c59304cd)
1; RUN: llc < %s -verify-machineinstrs -verify-coalescing
2;
3; This function has a PHI with one undefined input. Verify that PHIElimination
4; inserts an IMPLICIT_DEF instruction in the predecessor so all paths to the use
5; pass through a def.
6
7%struct.xx_stack = type { i32, ptr }
8
9define i32 @push(ptr %stack) nounwind uwtable readonly ssp {
10entry:
11  %tobool1 = icmp eq ptr %stack, null
12  br i1 %tobool1, label %for.end, label %for.body
13
14for.body:
15  %stack.addr.02 = phi ptr [ %0, %for.body ], [ %stack, %entry ]
16  %next = getelementptr inbounds %struct.xx_stack, ptr %stack.addr.02, i64 0, i32 1
17  %0 = load ptr, ptr %next, align 8
18  %tobool = icmp eq ptr %0, null
19  br i1 %tobool, label %for.end, label %for.body
20
21for.end:
22  %top.0.lcssa = phi ptr [ undef, %entry ], [ %stack.addr.02, %for.body ]
23  %1 = load i32, ptr %top.0.lcssa, align 4
24  ret i32 %1
25}
26