[llvm] [LoopVectorizer] Allow partial reductions to be made in predicated loops (PR #124268)

[James Chesterman via llvm-commits]

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@@ -1596,7 +1596,7 @@ define i32 @not_dotp_predicated_pragma(i64 %N, ptr %a, ptr %b) {
 ; CHECK-INTERLEAVE1:       vector.body:
 ; CHECK-INTERLEAVE1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_LOAD_CONTINUE62:%.*]] ]
 ; CHECK-INTERLEAVE1-NEXT:    [[VEC_IND:%.*]] = phi <16 x i64> [ <i64 0, i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, i64 10, i64 11, i64 12, i64 13, i64 14, i64 15>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[PRED_LOAD_CONTINUE62]] ]
-; CHECK-INTERLEAVE1-NEXT:    [[VEC_PHI:%.*]] = phi <16 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP180:%.*]], [[PRED_LOAD_CONTINUE62]] ]
+; CHECK-INTERLEAVE1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[PARTIAL_REDUCE:%.*]], [[PRED_LOAD_CONTINUE62]] ]
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JamesChesterman wrote:

Done.
I also added the `!7` to both `@dotp_predicated` tests, which made them almost the same as the `@dotp_predicated_pragma` tests, so the pragma tests have been removed.

https://github.com/llvm/llvm-project/pull/124268