mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-24 22:32:47 +00:00
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
43 lines
1.1 KiB
LLVM
43 lines
1.1 KiB
LLVM
; RUN: llc < %s -mtriple=armv7-apple-darwin -arm-atomic-cfg-tidy=0 | FileCheck %s
|
|
|
|
define double @f1() nounwind {
|
|
; CHECK-LABEL: f1:
|
|
; CHECK: .data_region
|
|
; CHECK: .long 1413754129
|
|
; CHECK: .long 1074340347
|
|
; CHECK: .end_data_region
|
|
ret double 0x400921FB54442D11
|
|
}
|
|
|
|
|
|
define i32 @f2() {
|
|
; CHECK-LABEL: f2:
|
|
; CHECK: .data_region jt32
|
|
; CHECK: .end_data_region
|
|
|
|
entry:
|
|
switch i32 undef, label %return [
|
|
i32 1, label %sw.bb
|
|
i32 2, label %sw.bb6
|
|
i32 3, label %sw.bb13
|
|
i32 4, label %sw.bb20
|
|
]
|
|
|
|
sw.bb: ; preds = %entry
|
|
br label %return
|
|
|
|
sw.bb6: ; preds = %entry
|
|
br label %return
|
|
|
|
sw.bb13: ; preds = %entry
|
|
br label %return
|
|
|
|
sw.bb20: ; preds = %entry
|
|
%div = sdiv i32 undef, undef
|
|
br label %return
|
|
|
|
return: ; preds = %sw.bb20, %sw.bb13, %sw.bb6, %sw.bb, %entry
|
|
%retval.0 = phi i32 [ %div, %sw.bb20 ], [ undef, %sw.bb13 ], [ undef, %sw.bb6 ], [ undef, %sw.bb ], [ 0, %entry ]
|
|
ret i32 %retval.0
|
|
}
|