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d0dbe02fd2
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
33 lines
1.0 KiB
LLVM
33 lines
1.0 KiB
LLVM
; RUN: llc < %s -mcpu=cortex-a8 -arm-atomic-cfg-tidy=0 | FileCheck %s
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; ModuleID = 'bugpoint-reduced-simplified.bc'
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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"
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target triple = "armv7--linux-gnueabi"
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; CHECK-LABEL: function
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define void @function() {
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; CHECK: cmp r0, #0
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; CHECK: bxne lr
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; CHECK: vmov.i32 q8, #0xff0000
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entry:
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br i1 undef, label %vector.body, label %for.end
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; CHECK: vld1.32 {d18, d19}, [r0]
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; CHECK: vand q10, q9, q8
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; CHECK: vbic.i16 q9, #0xff
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; CHECK: vorr q9, q9, q10
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; CHECK: vst1.32 {d18, d19}, [r0]
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vector.body:
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%wide.load = load <4 x i32>* undef, align 4
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%0 = and <4 x i32> %wide.load, <i32 -16711936, i32 -16711936, i32 -16711936, i32 -16711936>
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%1 = sub <4 x i32> %wide.load, zeroinitializer
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%2 = and <4 x i32> %1, <i32 16711680, i32 16711680, i32 16711680, i32 16711680>
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%3 = or <4 x i32> undef, %0
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%4 = or <4 x i32> %3, %2
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store <4 x i32> %4, <4 x i32>* undef, align 4
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br label %vector.body
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for.end:
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ret void
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}
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