[llvm] [VPlan] Lower BranchOnTwoConds to chain of 2 simple branches. (PR #174016)

[via llvm-commits]

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@@ -254,17 +251,16 @@ define i32 @diff_blocks_invariant_early_exit_cond(ptr %s) {
 ; CHECK-NEXT:    [[TMP1:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
 ; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; CHECK:       vector.body:
-; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY_COND_1:%.*]] ]
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
 ; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i32 [[INDEX_NEXT]], 276
-; CHECK-NEXT:    [[TMP3:%.*]] = or i1 [[TMP1]], [[TMP2]]
-; CHECK-NEXT:    br i1 [[TMP3]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
-; CHECK:       middle.split:
-; CHECK-NEXT:    br i1 [[TMP1]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; CHECK-NEXT:    br i1 [[TMP1]], label [[VECTOR_EARLY_EXIT:%.*]], label [[VECTOR_BODY_COND_1]]
+; CHECK:       vector.body.cond.1:
+; CHECK-NEXT:    br i1 [[TMP2]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    br label [[FOR_END:%.*]]
 ; CHECK:       vector.early.exit:
-; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK-NEXT:    br label [[EARLY_EXIT:%.*]]
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ayalz wrote:

Unrelated: opportunity to eliminate such empty vector.early.exit's?

https://github.com/llvm/llvm-project/pull/174016