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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
18 lines
639 B
LLVM
18 lines
639 B
LLVM
; RUN: llc < %s -O3 -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 -mcpu=cortex-a8 | FileCheck %s
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; Formerly crashed, 3573915.
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define void @RotateStarsFP_Vec() nounwind {
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bb.nph372:
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br label %bb8
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bb8: ; preds = %bb8, %bb.nph372
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%0 = fadd <4 x float> undef, <float 0xBFEE353F80000000, float 0xBFEE353F80000000, float 0xBFEE353F80000000, float 0xBFEE353F80000000>
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%1 = fmul <4 x float> %0, undef
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%2 = fmul <4 x float> %1, undef
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%3 = fadd <4 x float> undef, %2
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store <4 x float> %3, <4 x float>* undef, align 4
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br label %bb8
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; CHECK-LABEL: RotateStarsFP_Vec:
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; CHECK: vld1.64
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}
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