[X86][AVX] combineInsertSubvector - remove concat_vectors(load(x),load(x)) --> sub_vbroadcast(x)

RKSimon · RKSimon · commit f383a47b7db2 · 2019-02-23T18:53:03.000Z
D58053/rL354340 added this to EltsFromConsecutiveLoads directly

llvm-svn: 354732
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -41949,11 +41949,6 @@ static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG,
             return Ld;
         }
       }
-      // If lower/upper loads are the same and there's no other use of the lower
-      // load, then splat the loaded value with a broadcast.
-      if (auto *Ld = dyn_cast<LoadSDNode>(peekThroughOneUseBitcasts(SubVec2)))
-        if (SubVec2 == SubVec && ISD::isNormalLoad(Ld) && Vec.hasOneUse())
-          return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT, SubVec);
 
       // If this broadcast/subv_broadcast is inserted into both halves, use a
       // larger broadcast/subv_broadcast.

Original file line number	Diff line number	Diff line change
`@@ -41949,11 +41949,6 @@ static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG,`
`41949`	`41949`	`return Ld;`
`41950`	`41950`	`}`
`41951`	`41951`	`}`
`41952`		`- // If lower/upper loads are the same and there's no other use of the lower`
`41953`		`- // load, then splat the loaded value with a broadcast.`
`41954`		`- if (auto *Ld = dyn_cast<LoadSDNode>(peekThroughOneUseBitcasts(SubVec2)))`
`41955`		`- if (SubVec2 == SubVec && ISD::isNormalLoad(Ld) && Vec.hasOneUse())`
`41956`		`- return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT, SubVec);`
`41957`	`41952`
`41958`	`41953`	`// If this broadcast/subv_broadcast is inserted into both halves, use a`
`41959`	`41954`	`// larger broadcast/subv_broadcast.`