maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[PowerPC] Re-enable combine for i64 BSWAP on targets without LDBRX 

The combine was disabled in 4e22c7265d as it caused failures in
the ppc64be-multistage (bootstrap) bot.
It turns out that the combine did not correctly update the MMO for
the high load which caused aliased stores to be reported as unaliased.
This patch fixes that problem and re-enables the combine.
This commit is contained in:
Nemanja Ivanovic 2021-07-06 19:15:45 -05:00
parent f2d5fce86e
commit 3553698de7
3 changed files with 19 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
llvm/lib/Target/PowerPC/PPCISelLowering.cpp
View File

@ -15251,9 +15251,7 @@ SDValue PPCTargetLowering::PerformDAGCombine(SDNode *N,
LoadSDNode *LD = cast<LoadSDNode>(N->getOperand(0));
// Can't split volatile or atomic loads.
// FIXME: Disabling this to unblock the big endian bot until I can get it
// fixed.
if (!LD->isSimple() || !Subtarget.hasLDBRX())
if (!LD->isSimple())
return SDValue();
SDValue BasePtr = LD->getBasePtr();
SDValue Lo = DAG.getLoad(MVT::i32, dl, LD->getChain(), BasePtr,
@ -15261,8 +15259,9 @@ SDValue PPCTargetLowering::PerformDAGCombine(SDNode *N,
Lo = DAG.getNode(ISD::BSWAP, dl, MVT::i32, Lo);
BasePtr = DAG.getNode(ISD::ADD, dl, BasePtr.getValueType(), BasePtr,
DAG.getIntPtrConstant(4, dl));
SDValue Hi = DAG.getLoad(MVT::i32, dl, LD->getChain(), BasePtr,
LD->getPointerInfo(), LD->getAlignment());
MachineMemOperand *NewMMO = DAG.getMachineFunction().getMachineMemOperand(
LD->getMemOperand(), 4, 4);
SDValue Hi = DAG.getLoad(MVT::i32, dl, LD->getChain(), BasePtr, NewMMO);
Hi = DAG.getNode(ISD::BSWAP, dl, MVT::i32, Hi);
SDValue Res;
if (Subtarget.isLittleEndian())

19
llvm/test/CodeGen/PowerPC/bswap-load-store.ll
View File

@ -151,19 +151,12 @@ define i64 @LDBRX(i8* %ptr, i64 %off) {
;
; X64-LABEL: LDBRX:
; X64: # %bb.0:
; X64-NEXT: ldx r4, r3, r4
; X64-NEXT: rotldi r5, r4, 16
; X64-NEXT: rotldi r3, r4, 8
; X64-NEXT: rldimi r3, r5, 8, 48
; X64-NEXT: rotldi r5, r4, 24
; X64-NEXT: rldimi r3, r5, 16, 40
; X64-NEXT: rotldi r5, r4, 32
; X64-NEXT: rldimi r3, r5, 24, 32
; X64-NEXT: rotldi r5, r4, 48
; X64-NEXT: rldimi r3, r5, 40, 16
; X64-NEXT: rotldi r5, r4, 56
; X64-NEXT: rldimi r3, r5, 48, 8
; X64-NEXT: rldimi r3, r4, 56, 0
; X64-NEXT: li r6, 4
; X64-NEXT: lwbrx r5, r3, r4
; X64-NEXT: add r3, r3, r4
; X64-NEXT: lwbrx r3, r3, r6
; X64-NEXT: rldimi r5, r3, 32, 0
; X64-NEXT: mr r3, r5
; X64-NEXT: blr
;
; PWR7_64-LABEL: LDBRX:

36
llvm/test/CodeGen/PowerPC/ld-bswap64-no-ldbrx.ll
View File

@ -4,20 +4,11 @@
define void @bs(i64* %p) {
; CHECK-LABEL: bs:
; CHECK: # %bb.0:
; CHECK-NEXT: ld 4, 0(3)
; CHECK-NEXT: rotldi 5, 4, 16
; CHECK-NEXT: rotldi 6, 4, 8
; CHECK-NEXT: rldimi 6, 5, 8, 48
; CHECK-NEXT: rotldi 5, 4, 24
; CHECK-NEXT: rldimi 6, 5, 16, 40
; CHECK-NEXT: rotldi 5, 4, 32
; CHECK-NEXT: rldimi 6, 5, 24, 32
; CHECK-NEXT: rotldi 5, 4, 48
; CHECK-NEXT: rldimi 6, 5, 40, 16
; CHECK-NEXT: rotldi 5, 4, 56
; CHECK-NEXT: rldimi 6, 5, 48, 8
; CHECK-NEXT: rldimi 6, 4, 56, 0
; CHECK-NEXT: std 6, 0(3)
; CHECK-NEXT: li 4, 4
; CHECK-NEXT: lwbrx 5, 0, 3
; CHECK-NEXT: lwbrx 4, 3, 4
; CHECK-NEXT: rldimi 5, 4, 32, 0
; CHECK-NEXT: std 5, 0(3)
; CHECK-NEXT: blr
%x = load i64, i64* %p, align 8
%b = call i64 @llvm.bswap.i64(i64 %x)
@ -50,19 +41,10 @@ define i64 @volatile_ld(i64* %p) {
define i64 @misaligned_ld(i64* %p) {
; CHECK-LABEL: misaligned_ld:
; CHECK: # %bb.0:
; CHECK-NEXT: ld 4, 0(3)
; CHECK-NEXT: rotldi 5, 4, 16
; CHECK-NEXT: rotldi 3, 4, 8
; CHECK-NEXT: rldimi 3, 5, 8, 48
; CHECK-NEXT: rotldi 5, 4, 24
; CHECK-NEXT: rldimi 3, 5, 16, 40
; CHECK-NEXT: rotldi 5, 4, 32
; CHECK-NEXT: rldimi 3, 5, 24, 32
; CHECK-NEXT: rotldi 5, 4, 48
; CHECK-NEXT: rldimi 3, 5, 40, 16
; CHECK-NEXT: rotldi 5, 4, 56
; CHECK-NEXT: rldimi 3, 5, 48, 8
; CHECK-NEXT: rldimi 3, 4, 56, 0
; CHECK-NEXT: li 4, 4
; CHECK-NEXT: lwbrx 4, 3, 4
; CHECK-NEXT: lwbrx 3, 0, 3
; CHECK-NEXT: rldimi 3, 4, 32, 0
; CHECK-NEXT: blr
%x = load i64, i64* %p, align 1
%b = call i64 @llvm.bswap.i64(i64 %x)