- Revert some changes from 85044, 85045, and 85047 that broke x86_64 tests and

  bootstrapping. It's not safe to leave identity subreg_to_reg and insert_subreg
  around.
- Relax register scavenging to allow use of partially "not-live" registers. It's
  common for targets to operate on registers where the top bits are undef. e.g.
  s0 =
  d0 = insert_subreg d0<undef>, s0, 1
  ...
     = d0
  When the insert_subreg is eliminated by the coalescer, the scavenger used to
  complain. The previous fix was to keep to insert_subreg around. But that's
  brittle and it's overly conservative when we want to use the scavenger to 
  allocate registers. It's actually legal and desirable for other instructions
  to use the "undef" part of d0. e.g.
  s0 =
  d0 = insert_subreg d0<undef>, s0, 1
  ...
  s1 =
     = s1
     = d0
  We probably need add a "partial-undef" marker on machine operand so the
  machine verifier would not complain.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85091 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 171 insertions, 0 deletions

diff --git a/test/CodeGen/X86/2009-10-25-RewriterBug.ll b/test/CodeGen/X86/2009-10-25-RewriterBug.ll
new file mode 100644
index 0000000000..5b4e818359
--- /dev/null
+++ b/test/CodeGen/X86/2009-10-25-RewriterBug.ll
@@ -0,0 +1,171 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -relocation-model=pic -disable-fp-elim
+
+%struct.DecRefPicMarking_t = type { i32, i32, i32, i32, i32, %struct.DecRefPicMarking_t* }
+%struct.FrameStore = type { i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, %struct.StorablePicture*, %struct.StorablePicture*, %struct.StorablePicture* }
+%struct.StorablePicture = type { i32, i32, i32, i32, i32, [50 x [6 x [33 x i64]]], [50 x [6 x [33 x i64]]], [50 x [6 x [33 x i64]]], [50 x [6 x [33 x i64]]], i32, i32, i32, i32, i32, i32, i32, i32, i32, i16, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i16**, i16***, i8*, i16**, i8***, i64***, i64***, i16****, i8**, i8**, %struct.StorablePicture*, %struct.StorablePicture*, %struct.StorablePicture*, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, [2 x i32], i32, %struct.DecRefPicMarking_t*, i32 }
+
+define fastcc void @insert_picture_in_dpb(%struct.FrameStore* nocapture %fs, %struct.StorablePicture* %p) nounwind ssp {
+entry:
+  %0 = getelementptr inbounds %struct.FrameStore* %fs, i64 0, i32 12 ; <%struct.StorablePicture**> [#uses=1]
+  %1 = icmp eq i32 undef, 0                       ; <i1> [#uses=1]
+  br i1 %1, label %bb.i, label %bb36.i
+
+bb.i:                                             ; preds = %entry
+  br i1 undef, label %bb3.i, label %bb14.preheader.i
+
+bb3.i:                                            ; preds = %bb.i
+  unreachable
+
+bb14.preheader.i:                                 ; preds = %bb.i
+  br i1 undef, label %bb9.i, label %bb20.preheader.i
+
+bb9.i:                                            ; preds = %bb9.i, %bb14.preheader.i
+  br i1 undef, label %bb9.i, label %bb20.preheader.i
+
+bb20.preheader.i:                                 ; preds = %bb9.i, %bb14.preheader.i
+  br i1 undef, label %bb18.i, label %bb29.preheader.i
+
+bb18.i:                                           ; preds = %bb20.preheader.i
+  unreachable
+
+bb29.preheader.i:                                 ; preds = %bb20.preheader.i
+  br i1 undef, label %bb24.i, label %bb30.i
+
+bb24.i:                                           ; preds = %bb29.preheader.i
+  unreachable
+
+bb30.i:                                           ; preds = %bb29.preheader.i
+  store i32 undef, i32* undef, align 8
+  br label %bb67.preheader.i
+
+bb36.i:                                           ; preds = %entry
+  br label %bb67.preheader.i
+
+bb67.preheader.i:                                 ; preds = %bb36.i, %bb30.i
+  %2 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %3 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %4 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %5 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %6 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %7 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %8 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %9 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %10 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %11 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %12 = phi %struct.StorablePicture* [ null, %bb36.i ], [ undef, %bb30.i ] ; <%struct.StorablePicture*> [#uses=1]
+  br i1 undef, label %bb38.i, label %bb68.i
+
+bb38.i:                                           ; preds = %bb66.i, %bb67.preheader.i
+  %13 = phi %struct.StorablePicture* [ %37, %bb66.i ], [ %2, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %14 = phi %struct.StorablePicture* [ %38, %bb66.i ], [ %3, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %15 = phi %struct.StorablePicture* [ %39, %bb66.i ], [ %4, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %16 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %5, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %17 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %6, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %18 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %7, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %19 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %8, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %20 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %9, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %21 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %10, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %22 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %11, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %23 = phi %struct.StorablePicture* [ %40, %bb66.i ], [ %12, %bb67.preheader.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %indvar248.i = phi i64 [ %indvar.next249.i, %bb66.i ], [ 0, %bb67.preheader.i ] ; <i64> [#uses=3]
+  %storemerge52.i = trunc i64 %indvar248.i to i32 ; <i32> [#uses=1]
+  %24 = getelementptr inbounds %struct.StorablePicture* %23, i64 0, i32 19 ; <i32*> [#uses=0]
+  br i1 undef, label %bb.nph51.i, label %bb66.i
+
+bb.nph51.i:                                       ; preds = %bb38.i
+  %25 = sdiv i32 %storemerge52.i, 8               ; <i32> [#uses=0]
+  br label %bb39.i
+
+bb39.i:                                           ; preds = %bb64.i, %bb.nph51.i
+  %26 = phi %struct.StorablePicture* [ %17, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %27 = phi %struct.StorablePicture* [ %18, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %28 = phi %struct.StorablePicture* [ %19, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %29 = phi %struct.StorablePicture* [ %20, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %30 = phi %struct.StorablePicture* [ %21, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %31 = phi %struct.StorablePicture* [ %22, %bb.nph51.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=0]
+  br i1 undef, label %bb57.i, label %bb40.i
+
+bb40.i:                                           ; preds = %bb39.i
+  br i1 undef, label %bb57.i, label %bb41.i
+
+bb41.i:                                           ; preds = %bb40.i
+  %storemerge10.i = select i1 undef, i32 2, i32 4 ; <i32> [#uses=1]
+  %32 = zext i32 %storemerge10.i to i64           ; <i64> [#uses=1]
+  br i1 undef, label %bb45.i, label %bb47.i
+
+bb45.i:                                           ; preds = %bb41.i
+  %33 = getelementptr inbounds %struct.StorablePicture* %26, i64 0, i32 5, i64 undef, i64 %32, i64 undef ; <i64*> [#uses=1]
+  %34 = load i64* %33, align 8                    ; <i64> [#uses=1]
+  br label %bb47.i
+
+bb47.i:                                           ; preds = %bb45.i, %bb41.i
+  %storemerge11.i = phi i64 [ %34, %bb45.i ], [ 0, %bb41.i ] ; <i64> [#uses=0]
+  %scevgep246.i = getelementptr i64* undef, i64 undef ; <i64*> [#uses=0]
+  br label %bb64.i
+
+bb57.i:                                           ; preds = %bb40.i, %bb39.i
+  br i1 undef, label %bb58.i, label %bb60.i
+
+bb58.i:                                           ; preds = %bb57.i
+  br label %bb60.i
+
+bb60.i:                                           ; preds = %bb58.i, %bb57.i
+  %35 = load i64*** undef, align 8                ; <i64**> [#uses=1]
+  %scevgep256.i = getelementptr i64** %35, i64 %indvar248.i ; <i64**> [#uses=1]
+  %36 = load i64** %scevgep256.i, align 8         ; <i64*> [#uses=1]
+  %scevgep243.i = getelementptr i64* %36, i64 undef ; <i64*> [#uses=1]
+  store i64 -1, i64* %scevgep243.i, align 8
+  br label %bb64.i
+
+bb64.i:                                           ; preds = %bb60.i, %bb47.i
+  br i1 undef, label %bb39.i, label %bb66.i
+
+bb66.i:                                           ; preds = %bb64.i, %bb38.i
+  %37 = phi %struct.StorablePicture* [ %13, %bb38.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %38 = phi %struct.StorablePicture* [ %14, %bb38.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %39 = phi %struct.StorablePicture* [ %15, %bb38.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=2]
+  %40 = phi %struct.StorablePicture* [ %16, %bb38.i ], [ null, %bb64.i ] ; <%struct.StorablePicture*> [#uses=8]
+  %indvar.next249.i = add i64 %indvar248.i, 1     ; <i64> [#uses=1]
+  br i1 undef, label %bb38.i, label %bb68.i
+
+bb68.i:                                           ; preds = %bb66.i, %bb67.preheader.i
+  %41 = phi %struct.StorablePicture* [ %2, %bb67.preheader.i ], [ %37, %bb66.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %42 = phi %struct.StorablePicture* [ %3, %bb67.preheader.i ], [ %38, %bb66.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %43 = phi %struct.StorablePicture* [ %4, %bb67.preheader.i ], [ %39, %bb66.i ] ; <%struct.StorablePicture*> [#uses=1]
+  br i1 undef, label %bb.nph48.i, label %bb108.i
+
+bb.nph48.i:                                       ; preds = %bb68.i
+  br label %bb80.i
+
+bb80.i:                                           ; preds = %bb104.i, %bb.nph48.i
+  %44 = phi %struct.StorablePicture* [ %42, %bb.nph48.i ], [ null, %bb104.i ] ; <%struct.StorablePicture*> [#uses=1]
+  %45 = phi %struct.StorablePicture* [ %43, %bb.nph48.i ], [ null, %bb104.i ] ; <%struct.StorablePicture*> [#uses=1]
+  br i1 undef, label %bb.nph39.i, label %bb104.i
+
+bb.nph39.i:                                       ; preds = %bb80.i
+  br label %bb81.i
+
+bb81.i:                                           ; preds = %bb102.i, %bb.nph39.i
+  %46 = phi %struct.StorablePicture* [ %44, %bb.nph39.i ], [ %48, %bb102.i ] ; <%struct.StorablePicture*> [#uses=0]
+  %47 = phi %struct.StorablePicture* [ %45, %bb.nph39.i ], [ %48, %bb102.i ] ; <%struct.StorablePicture*> [#uses=0]
+  br i1 undef, label %bb83.i, label %bb82.i
+
+bb82.i:                                           ; preds = %bb81.i
+  br i1 undef, label %bb83.i, label %bb101.i
+
+bb83.i:                                           ; preds = %bb82.i, %bb81.i
+  br label %bb102.i
+
+bb101.i:                                          ; preds = %bb82.i
+  br label %bb102.i
+
+bb102.i:                                          ; preds = %bb101.i, %bb83.i
+  %48 = load %struct.StorablePicture** %0, align 8 ; <%struct.StorablePicture*> [#uses=2]
+  br i1 undef, label %bb81.i, label %bb104.i
+
+bb104.i:                                          ; preds = %bb102.i, %bb80.i
+  br label %bb80.i
+
+bb108.i:                                          ; preds = %bb68.i
+  unreachable
+}