[llvm] [VPlan] Update VPInst::onlyFirstLaneUsed to check users. (PR #80269)

[via llvm-commits]

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@@ -139,46 +139,42 @@ define void @pr45679(ptr %A) optsize {
 ; VF1UF4:       vector.ph:
 ; VF1UF4-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; VF1UF4:       vector.body:
-; VF1UF4-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE12:%.*]] ]
-; VF1UF4-NEXT:    [[VEC_IV:%.*]] = add i32 [[INDEX]], 0
-; VF1UF4-NEXT:    [[VEC_IV4:%.*]] = add i32 [[INDEX]], 1
-; VF1UF4-NEXT:    [[VEC_IV5:%.*]] = add i32 [[INDEX]], 2
-; VF1UF4-NEXT:    [[VEC_IV6:%.*]] = add i32 [[INDEX]], 3
-; VF1UF4-NEXT:    [[TMP0:%.*]] = icmp ule i32 [[VEC_IV]], 13
-; VF1UF4-NEXT:    [[TMP1:%.*]] = icmp ule i32 [[VEC_IV4]], 13
-; VF1UF4-NEXT:    [[TMP2:%.*]] = icmp ule i32 [[VEC_IV5]], 13
-; VF1UF4-NEXT:    [[TMP3:%.*]] = icmp ule i32 [[VEC_IV6]], 13
-; VF1UF4-NEXT:    br i1 [[TMP0]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
+; VF1UF4-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE6:%.*]] ]
+; VF1UF4-NEXT:    [[TMP0:%.*]] = add i32 [[INDEX]], 0
+; VF1UF4-NEXT:    [[TMP1:%.*]] = add i32 [[INDEX]], 1
+; VF1UF4-NEXT:    [[TMP2:%.*]] = add i32 [[INDEX]], 2
+; VF1UF4-NEXT:    [[TMP3:%.*]] = add i32 [[INDEX]], 3
+; VF1UF4-NEXT:    [[TMP4:%.*]] = icmp ule i32 [[TMP0]], 13
+; VF1UF4-NEXT:    [[TMP5:%.*]] = icmp ule i32 [[TMP1]], 13
+; VF1UF4-NEXT:    [[TMP6:%.*]] = icmp ule i32 [[TMP2]], 13
+; VF1UF4-NEXT:    [[TMP7:%.*]] = icmp ule i32 [[TMP3]], 13
+; VF1UF4-NEXT:    br i1 [[TMP4]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
 ; VF1UF4:       pred.store.if:
-; VF1UF4-NEXT:    [[INDUCTION:%.*]] = add i32 [[INDEX]], 0
-; VF1UF4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i32 [[INDUCTION]]
-; VF1UF4-NEXT:    store i32 13, ptr [[TMP4]], align 1
+; VF1UF4-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i32 [[TMP0]]
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ayalz wrote:

Noting: this is cse'ing TMP0 (as with TMP1,2,3 below), compared to currently re-computing it. In this case, should be dropped being a zero-add.

https://github.com/llvm/llvm-project/pull/80269