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[PowerPC] stop reverse mem op generation for some cases. 

We should consider the feeder user number when we do reverse memory
operation transformation. Otherwise, we may get negative impact.

Reviewed By: nemanjai

Differential Revision: https://reviews.llvm.org/D100166
This commit is contained in:
Chen Zheng 2021-04-12 21:28:31 -04:00
parent e50aa1af2d
commit 80aa9b0f7b
2 changed files with 14 additions and 5 deletions
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11
llvm/lib/Target/PowerPC/PPCISelLowering.cpp
View File

@ -14403,6 +14403,11 @@ SDValue PPCTargetLowering::combineVReverseMemOP(ShuffleVectorSDNode *SVN,
return SDValue();
if (LSBase->getOpcode() == ISD::LOAD) {
// If the load has more than one user except the shufflevector instruction,
// it is not profitable to replace the shufflevector with a reverse load.
if (!LSBase->hasOneUse())
return SDValue();
SDLoc dl(SVN);
SDValue LoadOps[] = {LSBase->getChain(), LSBase->getBasePtr()};
return DAG.getMemIntrinsicNode(
@ -14411,6 +14416,12 @@ SDValue PPCTargetLowering::combineVReverseMemOP(ShuffleVectorSDNode *SVN,
}
if (LSBase->getOpcode() == ISD::STORE) {
// If there are other uses of the shuffle, the swap cannot be avoided.
// Forcing the use of an X-Form (since swapped stores only have
// X-Forms) without removing the swap is unprofitable.
if (!SVN->hasOneUse())
return SDValue();
SDLoc dl(LSBase);
SDValue StoreOps[] = {LSBase->getChain(), SVN->getOperand(0),
LSBase->getBasePtr()};

8
llvm/test/CodeGen/PowerPC/vsx-shuffle-le-multiple-uses.ll
View File

@ -7,8 +7,8 @@ define <2 x double> @loadHasMultipleUses(<2 x double>* %p1, <2 x double>* %p2) {
; CHECK-LABEL: loadHasMultipleUses:
; CHECK: # %bb.0:
; CHECK-NEXT: lxv 0, 0(3)
; CHECK-NEXT: xxswapd 34, 0
; CHECK-NEXT: stxv 0, 0(4)
; CHECK-NEXT: lxvd2x 34, 0, 3
; CHECK-NEXT: blr
%v1 = load <2 x double>, <2 x double>* %p1
store <2 x double> %v1, <2 x double>* %p2, align 16
@ -19,10 +19,8 @@ define <2 x double> @loadHasMultipleUses(<2 x double>* %p1, <2 x double>* %p2) {
define <2 x double> @storeHasMultipleUses(<2 x double> %v, <2 x double>* %p) {
; CHECK-LABEL: storeHasMultipleUses:
; CHECK: # %bb.0:
; CHECK-NEXT: xxswapd 0, 34
; CHECK-NEXT: addi 3, 5, 256
; CHECK-NEXT: stxvd2x 34, 0, 3
; CHECK-NEXT: xxlor 34, 0, 0
; CHECK-NEXT: xxswapd 34, 34
; CHECK-NEXT: stxv 34, 256(5)
; CHECK-NEXT: blr
%v1 = shufflevector <2 x double> %v, <2 x double> %v, <2 x i32> < i32 1, i32 0>
%addr = getelementptr inbounds <2 x double>, <2 x double>* %p, i64 16