llvm-capstone/llvm/test/Analysis/MemorySSA/pr40749.ll
Alina Sbirlea fcfa7c5f92 [MemorySSA] Make insertDef insert corresponding phi nodes.
Summary:
The original assumption for the insertDef method was that it would not
materialize Defs out of no-where, hence it will not insert phis needed
after inserting a Def.

However, when cloning an instruction (use case used in LICM), we do
materialize Defs "out of no-where". If the block receiving a Def has at
least one other Def, then no processing is needed. If the block just
received its first Def, we must check where Phi placement is needed.
The only new usage of insertDef is in LICM, hence the trigger for the bug.

But the original goal of the method also fails to apply for the move()
method. If we move a Def from the entry point of a diamond to either the
left or right blocks, then the merge block must add a phi.
While this usecase does not currently occur, or may be viewed as an
incorrect transformation, MSSA must behave corectly given the scenario.

Resolves PR40749 and PR40754.

Reviewers: george.burgess.iv

Subscribers: sanjoy, jlebar, Prazek, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58652

llvm-svn: 355040
2019-02-27 22:20:22 +00:00

59 lines
1.9 KiB
LLVM

; RUN: opt -licm -enable-mssa-loop-dependency -verify-memoryssa -S < %s | FileCheck %s
; REQUIRES: asserts
target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64"
target triple = "systemz-unknown"
@g_3 = external dso_local local_unnamed_addr global i32, align 4
@g_57 = external dso_local local_unnamed_addr global i8, align 2
@g_82 = external dso_local global [8 x i16], align 2
@g_107 = external dso_local local_unnamed_addr global i32, align 4
define internal fastcc void @foo1() unnamed_addr{
; CHECK-LABEL: @foo1()
entry:
%.pre.pre = load i32, i32* @g_3, align 4
br label %loop1
loop1:
%tmp0 = phi i32 [ undef, %entry ], [ %var18.lcssa, %loopexit ]
br label %preheader
preheader:
%indvars.iv = phi i64 [ 0, %loop1 ], [ %indvars.iv.next, %loop6 ]
%phi18 = phi i32 [ %tmp0, %loop1 ], [ 0, %loop6 ]
%phi87 = phi i32 [ 0, %loop1 ], [ %tmp7, %loop6 ]
%tmp1 = getelementptr inbounds [8 x i16], [8 x i16]* @g_82, i64 0, i64 %indvars.iv
%tmp2 = load i16, i16* %tmp1, align 2
%tmp3 = trunc i16 %tmp2 to i8
store i8 %tmp3, i8* @g_57, align 2
store i32 8, i32* @g_107, align 4
%tmp4 = icmp eq i32 %.pre.pre, 0
%spec.select = select i1 %tmp4, i32 %phi18, i32 14
%tmp5 = trunc i64 %indvars.iv to i32
switch i32 %spec.select, label %loopexit [
i32 0, label %loop6
i32 14, label %loop9
]
loop6:
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%tmp7 = add nuw nsw i32 %phi87, 1
%tmp8 = icmp ult i64 %indvars.iv.next, 6
br i1 %tmp8, label %preheader, label %loop9
loop9:
%phi8.lcssa = phi i32 [ %tmp5, %preheader ], [ %tmp7, %loop6 ]
%tmp10 = trunc i32 %phi8.lcssa to i8
%tmp11 = tail call i16* @func_101(i16* getelementptr inbounds ([8 x i16], [8 x i16]* @g_82, i64 0, i64 6), i16* undef, i8 zeroext %tmp10)
unreachable
loopexit:
%var18.lcssa = phi i32 [ %phi18, %preheader ]
br label %loop1
}
declare dso_local i16* @func_101(i16*, i16*, i8) local_unnamed_addr