mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-29 23:12:55 +01:00
3bb84c9bcc
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 llvm-svn: 209883
43 lines
1.2 KiB
LLVM
43 lines
1.2 KiB
LLVM
; RUN: llc < %s -mtriple=thumbv8 -print-machineinstrs=if-converter -arm-atomic-cfg-tidy=0 -o /dev/null 2>&1 | FileCheck %s
|
|
|
|
%struct.S = type { i8* (i8*)*, [1 x i8] }
|
|
define internal zeroext i8 @bar(%struct.S* %x, %struct.S* nocapture %y) nounwind readonly {
|
|
entry:
|
|
%0 = getelementptr inbounds %struct.S* %x, i32 0, i32 1, i32 0
|
|
%1 = load i8* %0, align 1
|
|
%2 = zext i8 %1 to i32
|
|
%3 = and i32 %2, 112
|
|
%4 = icmp eq i32 %3, 0
|
|
br i1 %4, label %return, label %bb
|
|
|
|
bb:
|
|
%5 = getelementptr inbounds %struct.S* %y, i32 0, i32 1, i32 0
|
|
%6 = load i8* %5, align 1
|
|
%7 = zext i8 %6 to i32
|
|
%8 = and i32 %7, 112
|
|
%9 = icmp eq i32 %8, 0
|
|
br i1 %9, label %return, label %bb2
|
|
|
|
; CHECK: BB#2: derived from LLVM BB %bb2
|
|
; CHECK: Successors according to CFG: BB#3(192) BB#4(192)
|
|
|
|
bb2:
|
|
%v10 = icmp eq i32 %3, 16
|
|
br i1 %v10, label %bb4, label %bb3, !prof !0
|
|
|
|
bb3:
|
|
%v11 = icmp eq i32 %8, 16
|
|
br i1 %v11, label %bb4, label %return, !prof !1
|
|
|
|
bb4:
|
|
%v12 = ptrtoint %struct.S* %x to i32
|
|
%phitmp = trunc i32 %v12 to i8
|
|
ret i8 %phitmp
|
|
|
|
return:
|
|
ret i8 1
|
|
}
|
|
|
|
!0 = metadata !{metadata !"branch_weights", i32 4, i32 12}
|
|
!1 = metadata !{metadata !"branch_weights", i32 8, i32 16}
|