llvm/test/CodeGen/Generic/undef-phi.ll
Jakob Stoklund Olesen a4e6397fd9 Enforce stricter liveness rules for PHIs.
Verify that all paths from the entry block to a virtual register read
pass through a def. Enable this check even when MRI->isSSA() is false.

Verify that the live range of a virtual register is live out of all
predecessor blocks, even for PHI-values.

This requires that PHIElimination sometimes inserts IMPLICIT_DEF
instruction in predecessor blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159150 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-25 18:18:27 +00:00

27 lines
1015 B
LLVM

; RUN: llc < %s -verify-machineinstrs -verify-coalescing
;
; This function has a PHI with one undefined input. Verify that PHIElimination
; inserts an IMPLICIT_DEF instruction in the predecessor so all paths to the use
; pass through a def.
%struct.xx_stack = type { i32, %struct.xx_stack* }
define i32 @push(%struct.xx_stack* %stack) nounwind uwtable readonly ssp {
entry:
%tobool1 = icmp eq %struct.xx_stack* %stack, null
br i1 %tobool1, label %for.end, label %for.body
for.body:
%stack.addr.02 = phi %struct.xx_stack* [ %0, %for.body ], [ %stack, %entry ]
%next = getelementptr inbounds %struct.xx_stack* %stack.addr.02, i64 0, i32 1
%0 = load %struct.xx_stack** %next, align 8
%tobool = icmp eq %struct.xx_stack* %0, null
br i1 %tobool, label %for.end, label %for.body
for.end:
%top.0.lcssa = phi %struct.xx_stack* [ undef, %entry ], [ %stack.addr.02, %for.body ]
%first = getelementptr inbounds %struct.xx_stack* %top.0.lcssa, i64 0, i32 0
%1 = load i32* %first, align 4
ret i32 %1
}