mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 19:52:54 +01:00
3bb84c9bcc
The C and C++ semantics for compare_exchange require it to return a bool
indicating success. This gets mapped to LLVM IR which follows each cmpxchg with
an icmp of the value loaded against the desired value.
When lowered to ldxr/stxr loops, this extra comparison is redundant: its
results are implicit in the control-flow of the function.
This commit makes two changes: it replaces that icmp with appropriate PHI
nodes, and then makes sure earlyCSE is called after expansion to actually make
use of the opportunities revealed.
I've also added -{arm,aarch64}-enable-atomic-tidy options, so that
existing fragile tests aren't perturbed too much by the change. Many
of them either rely on undef/unreachable too pervasively to be
restored to something well-defined (particularly while making sure
they test the same obscure assert from many years ago), or depend on a
particular CFG shape, which is disrupted by SimplifyCFG.
rdar://problem/16227836
llvm-svn: 209883
12 lines
293 B
LLVM
12 lines
293 B
LLVM
; RUN: llc -march=arm64 -mtriple=arm64-apple-ios -aarch64-atomic-cfg-tidy=0 < %s | FileCheck %s
|
|
; rdar://11935841
|
|
|
|
define void @t1() nounwind ssp {
|
|
entry:
|
|
; CHECK-LABEL: t1:
|
|
; CHECK-NOT: add x{{[0-9]+}}, sp
|
|
; CHECK: stp x28, x27, [sp, #-16]!
|
|
%v = alloca [288 x i32], align 4
|
|
unreachable
|
|
}
|