[llvm] [LoopUnroll] Introduce parallel reduction phis when unrolling. (PR #149470)

[Florian Hahn via llvm-commits]

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@@ -603,27 +603,33 @@ define i32 @test_add_reduction_unroll_partial(ptr %a, i64 noundef %n) {
 ; OTHER-NEXT:    br label %[[LOOP:.*]]
 ; OTHER:       [[LOOP]]:
 ; OTHER-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT_3:%.*]], %[[LOOP]] ]
-; OTHER-NEXT:    [[RDX:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[RDX_NEXT_3:%.*]], %[[LOOP]] ]
+; OTHER-NEXT:    [[RDX_1:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[RDX_NEXT_1:%.*]], %[[LOOP]] ]
+; OTHER-NEXT:    [[RDX_2:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[RDX_NEXT_2:%.*]], %[[LOOP]] ]
+; OTHER-NEXT:    [[RDX_3:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[RDX_NEXT_3:%.*]], %[[LOOP]] ]
+; OTHER-NEXT:    [[RDX:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[RDX_NEXT:%.*]], %[[LOOP]] ]
 ; OTHER-NEXT:    [[GEP_A:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[IV]]
 ; OTHER-NEXT:    [[TMP0:%.*]] = load i32, ptr [[GEP_A]], align 2
-; OTHER-NEXT:    [[RDX_NEXT:%.*]] = add nuw nsw i32 [[RDX]], [[TMP0]]
+; OTHER-NEXT:    [[RDX_NEXT]] = add nuw nsw i32 [[RDX]], [[TMP0]]
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fhahn wrote:

Ah yes, dropped the poison-generating flags for now, thanks

https://github.com/llvm/llvm-project/pull/149470