mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-26 21:32:10 +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
33 lines
893 B
LLVM
33 lines
893 B
LLVM
; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-atomic-cfg-tidy=0 | FileCheck %s
|
|
|
|
; If ARMBaseInstrInfo::AnalyzeBlocks returns the wrong value, which was possible
|
|
; for blocks with indirect branches, the IfConverter could end up deleting
|
|
; blocks that were the destinations of indirect branches, leaving branches to
|
|
; nowhere.
|
|
; <rdar://problem/14464830>
|
|
|
|
define i32 @preserve_blocks(i32 %x) {
|
|
; preserve_blocks:
|
|
; CHECK: Block address taken
|
|
; CHECK: movs r0, #2
|
|
; CHECK: movs r0, #1
|
|
; CHECK-NOT: Address of block that was removed by CodeGen
|
|
entry:
|
|
%c2 = icmp slt i32 %x, 3
|
|
%blockaddr = select i1 %c2, i8* blockaddress(@preserve_blocks, %ibt1), i8* blockaddress(@preserve_blocks, %ibt2)
|
|
%c1 = icmp eq i32 %x, 0
|
|
br i1 %c1, label %pre_ib, label %nextblock
|
|
|
|
nextblock:
|
|
ret i32 3
|
|
|
|
ibt1:
|
|
ret i32 2
|
|
|
|
ibt2:
|
|
ret i32 1
|
|
|
|
pre_ib:
|
|
indirectbr i8* %blockaddr, [ label %ibt1, label %ibt2 ]
|
|
}
|