[llvm] [VPlan] Add VPInstruction to unpack vector values to scalars. (PR #155670)

[via llvm-commits]

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@@ -205,25 +205,25 @@ define void @test_load_gep_widen_induction(ptr noalias %dst, ptr noalias %dst2)
 ; CHECK-NEXT:    [[STEP_ADD_2:%.*]] = add <2 x i64> [[STEP_ADD]], splat (i64 2)
 ; CHECK-NEXT:    [[STEP_ADD_3:%.*]] = add <2 x i64> [[STEP_ADD_2]], splat (i64 2)
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i128, ptr [[DST]], <2 x i64> [[VEC_IND]]
+; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x ptr> [[TMP0]], i32 0
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x ptr> [[TMP0]], i32 1
 ; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr i128, ptr [[DST]], <2 x i64> [[STEP_ADD]]
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x ptr> [[TMP1]], i32 0
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x ptr> [[TMP1]], i32 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr i128, ptr [[DST]], <2 x i64> [[STEP_ADD_2]]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x ptr> [[TMP2]], i32 0
+; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x ptr> [[TMP2]], i32 1
 ; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i128, ptr [[DST]], <2 x i64> [[STEP_ADD_3]]
-; CHECK-NEXT:    [[TMP4:%.*]] = extractelement <2 x ptr> [[TMP0]], i32 0
-; CHECK-NEXT:    store ptr null, ptr [[TMP4]], align 8
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x ptr> [[TMP0]], i32 1
+; CHECK-NEXT:    [[TMP11:%.*]] = extractelement <2 x ptr> [[TMP3]], i32 0
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x ptr> [[TMP3]], i32 1
 ; CHECK-NEXT:    store ptr null, ptr [[TMP5]], align 8
-; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x ptr> [[TMP1]], i32 0
 ; CHECK-NEXT:    store ptr null, ptr [[TMP6]], align 8
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x ptr> [[TMP1]], i32 1
 ; CHECK-NEXT:    store ptr null, ptr [[TMP7]], align 8
-; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x ptr> [[TMP2]], i32 0
 ; CHECK-NEXT:    store ptr null, ptr [[TMP8]], align 8
-; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x ptr> [[TMP2]], i32 1
 ; CHECK-NEXT:    store ptr null, ptr [[TMP9]], align 8
-; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x ptr> [[TMP3]], i32 0
 ; CHECK-NEXT:    store ptr null, ptr [[TMP10]], align 8
-; CHECK-NEXT:    [[TMP11:%.*]] = extractelement <2 x ptr> [[TMP3]], i32 1
 ; CHECK-NEXT:    store ptr null, ptr [[TMP11]], align 8
+; CHECK-NEXT:    store ptr null, ptr [[TMP17]], align 8
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ayalz wrote:

Ah, ok: this store to TMP17 replaces the one to TMP11, which is retained but TMP11 is redefined.

Wonder if some simple "sink each ExtractElement to before its single/first user" pass could help confirm all test differences?

https://github.com/llvm/llvm-project/pull/155670