[ScopDetection] If a loop is not part of a scop, none of it backedges can be

This patch makes sure that in case a loop is not fully contained within a region
that later forms a SCoP, none of the loop backedges are allowed to be part of
the region. We currently do not support the situation where only some of a loops
backedges are part of a scop. Today, this can break both scop modeling and code
generation. One such breaking test case is for example
test/ScopDetectionDiagnostics/loop_partially_in_scop-2.ll, where we totally
forgot to code generate some of the backedges. Fortunately, it is commonly not
necessary to support these partial loops, it is way more common that either
no backedge is included in a region or all loop backedge are included.

This fixes a recent miscompile in
MultiSource/Benchmarks/MiBench/consumer-typeset which was exposed after
r306477.

llvm-svn: 308113

1 files changed, 0 insertions, 49 deletions

diff --git a/polly/test/Isl/CodeGen/loop_partially_in_scop.ll b/polly/test/Isl/CodeGen/loop_partially_in_scop.ll
deleted file mode 100644
index 3cf7f1e73cb..00000000000
--- a/polly/test/Isl/CodeGen/loop_partially_in_scop.ll
+++ /dev/null
@@ -1,49 +0,0 @@
-; RUN: opt %loadPolly -S -polly-codegen < %s | FileCheck %s
-;
-; Verify we do not crash for this test case and additionally check the code
-; that we generate for the %tmp PHI node in the non-affine region. This code
-; is difficult to generate as some incoming edges are from basic blocks
-; from within the region and others from basic blocks from outside of the
-; non-affine region. As visible in the CHECK lines, the code we generate
-; currently loads from the PHI twice in %polly.stmt.bb2.entry, which is
-; something we should avoid.
-;
-; CHECK: polly.start
-
-; CHECK: polly.stmt.bb2.entry:                             ; preds = %polly.start
-; CHECK-NEXT:   %tmp.phiops.reload = load i32, i32* %tmp.phiops
-; CHECK-NEXT:   br label %polly.stmt.bb2
-
-; CHECK: polly.stmt.bb2:                                   ; preds = %polly.stmt.bb2, %polly.stmt.bb2.entry
-; CHECK-NEXT:   %polly.tmp = phi i32 [ %tmp.phiops.reload, %polly.stmt.bb2.entry ], [ %p_tmp4, %polly.stmt.bb2 ]
-; CHECK-NEXT:   %p_tmp3 = or i32 undef, undef
-; CHECK-NEXT:   %p_tmp4 = udiv i32 %p_tmp3, 10
-; CHECK-NEXT:   %p_tmp6 = icmp eq i8 undef, 0
-; CHECK-NEXT:   br i1 %p_tmp6, label %polly.stmt.polly.merge_new_and_old.exit, label %polly.stmt.bb2
-
-target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
-
-define void @baz(i32 %before) {
-bb:
-  br label %bb1
-
-bb1:                                              ; preds = %bb
-  br label %bb2
-
-bb2:                                              ; preds = %bb8, %bb7, %bb2, %bb1
-  %tmp = phi i32 [ %before, %bb1 ], [ 0, %bb8 ], [ %tmp4, %bb7 ], [ %tmp4, %bb2 ]
-  %tmp3 = or i32 undef, undef
-  %tmp4 = udiv i32 %tmp3, 10
-  %tmp5 = trunc i32 undef to i8
-  %tmp6 = icmp eq i8 %tmp5, 0
-  br i1 %tmp6, label %bb7, label %bb2
-
-bb7:                                              ; preds = %bb2
-  br i1 undef, label %bb8, label %bb2
-
-bb8:                                              ; preds = %bb7
-  br i1 undef, label %bb9, label %bb2
-
-bb9:                                              ; preds = %bb8
-  unreachable
-}