Allow for loops in LiveIntervals::pruneValue().

It is possible that the live range of the value being pruned loops back
into the kill MBB where the search started. When that happens, make sure
that the beginning of KillMBB is also pruned.

Instead of starting a DFS at KillMBB and skipping the root of the
search, start a DFS at each KillMBB successor, and allow the search to
loop back to KillMBB.

This fixes PR14078.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165872 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 49 insertions, 0 deletions

diff --git a/test/CodeGen/ARM/coalesce-subregs.ll b/test/CodeGen/ARM/coalesce-subregs.ll
index 6e1f17d..9a94349 100644
--- a/test/CodeGen/ARM/coalesce-subregs.ll
+++ b/test/CodeGen/ARM/coalesce-subregs.ll
@@ -214,3 +214,52 @@ loop.end:
  %d.end = phi double [ 0.0, %entry ], [ %add, %after_inner_loop ]
  ret void
 }
+
+; CHECK: pr14078
+define arm_aapcs_vfpcc i32 @pr14078(i8* nocapture %arg, i8* nocapture %arg1, i32 %arg2) nounwind uwtable readonly {
+bb:
+  br i1 undef, label %bb31, label %bb3
+
+bb3:                                              ; preds = %bb12, %bb
+  %tmp = shufflevector <2 x i64> undef, <2 x i64> undef, <1 x i32> zeroinitializer
+  %tmp4 = bitcast <1 x i64> %tmp to <2 x float>
+  %tmp5 = shufflevector <2 x float> %tmp4, <2 x float> undef, <4 x i32> zeroinitializer
+  %tmp6 = bitcast <4 x float> %tmp5 to <2 x i64>
+  %tmp7 = shufflevector <2 x i64> %tmp6, <2 x i64> undef, <1 x i32> zeroinitializer
+  %tmp8 = bitcast <1 x i64> %tmp7 to <2 x float>
+  %tmp9 = tail call <2 x float> @baz(<2 x float> <float 0xFFFFFFFFE0000000, float 0.000000e+00>, <2 x float> %tmp8, <2 x float> zeroinitializer) nounwind
+  br i1 undef, label %bb10, label %bb12
+
+bb10:                                             ; preds = %bb3
+  %tmp11 = load <4 x float>* undef, align 8
+  br label %bb12
+
+bb12:                                             ; preds = %bb10, %bb3
+  %tmp13 = shufflevector <2 x float> %tmp9, <2 x float> zeroinitializer, <2 x i32> <i32 0, i32 2>
+  %tmp14 = bitcast <2 x float> %tmp13 to <1 x i64>
+  %tmp15 = shufflevector <1 x i64> %tmp14, <1 x i64> zeroinitializer, <2 x i32> <i32 0, i32 1>
+  %tmp16 = bitcast <2 x i64> %tmp15 to <4 x float>
+  %tmp17 = fmul <4 x float> zeroinitializer, %tmp16
+  %tmp18 = bitcast <4 x float> %tmp17 to <2 x i64>
+  %tmp19 = shufflevector <2 x i64> %tmp18, <2 x i64> undef, <1 x i32> zeroinitializer
+  %tmp20 = bitcast <1 x i64> %tmp19 to <2 x float>
+  %tmp21 = tail call <2 x float> @baz67(<2 x float> %tmp20, <2 x float> undef) nounwind
+  %tmp22 = tail call <2 x float> @baz67(<2 x float> %tmp21, <2 x float> %tmp21) nounwind
+  %tmp23 = shufflevector <2 x float> %tmp22, <2 x float> undef, <4 x i32> zeroinitializer
+  %tmp24 = bitcast <4 x float> %tmp23 to <2 x i64>
+  %tmp25 = shufflevector <2 x i64> %tmp24, <2 x i64> undef, <1 x i32> zeroinitializer
+  %tmp26 = bitcast <1 x i64> %tmp25 to <2 x float>
+  %tmp27 = extractelement <2 x float> %tmp26, i32 0
+  %tmp28 = fcmp olt float %tmp27, 0.000000e+00
+  %tmp29 = select i1 %tmp28, i32 0, i32 undef
+  %tmp30 = icmp ult i32 undef, %arg2
+  br i1 %tmp30, label %bb3, label %bb31
+
+bb31:                                             ; preds = %bb12, %bb
+  %tmp32 = phi i32 [ 1, %bb ], [ %tmp29, %bb12 ]
+  ret i32 %tmp32
+}
+
+declare <2 x float> @baz(<2 x float>, <2 x float>, <2 x float>) nounwind readnone
+
+declare <2 x float> @baz67(<2 x float>, <2 x float>) nounwind readnone