llvm-6502/test/CodeGen/ARM/2013-07-29-vector-or-combine.ll
Tim Northover d0dbe02fd2 ARM & AArch64: make use of common cmpxchg idioms after expansion
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209883 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-30 10:09:59 +00:00

33 lines
1.0 KiB
LLVM

; RUN: llc < %s -mcpu=cortex-a8 -arm-atomic-cfg-tidy=0 | FileCheck %s
; ModuleID = 'bugpoint-reduced-simplified.bc'
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32-S64"
target triple = "armv7--linux-gnueabi"
; CHECK-LABEL: function
define void @function() {
; CHECK: cmp r0, #0
; CHECK: bxne lr
; CHECK: vmov.i32 q8, #0xff0000
entry:
br i1 undef, label %vector.body, label %for.end
; CHECK: vld1.32 {d18, d19}, [r0]
; CHECK: vand q10, q9, q8
; CHECK: vbic.i16 q9, #0xff
; CHECK: vorr q9, q9, q10
; CHECK: vst1.32 {d18, d19}, [r0]
vector.body:
%wide.load = load <4 x i32>* undef, align 4
%0 = and <4 x i32> %wide.load, <i32 -16711936, i32 -16711936, i32 -16711936, i32 -16711936>
%1 = sub <4 x i32> %wide.load, zeroinitializer
%2 = and <4 x i32> %1, <i32 16711680, i32 16711680, i32 16711680, i32 16711680>
%3 = or <4 x i32> undef, %0
%4 = or <4 x i32> %3, %2
store <4 x i32> %4, <4 x i32>* undef, align 4
br label %vector.body
for.end:
ret void
}