The introduction of indirectbr meant the introduction of

unsplittable critical edges, which means the introduction of
loops which cannot be transformed to LoopSimplify form. Fix
LoopSimplify to avoid transforming such loops into invalid
code.

llvm-svn: 86176

1 files changed, 83 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopSimplify/indirectbr.ll b/llvm/test/Transforms/LoopSimplify/indirectbr.ll
new file mode 100644
index 00000000000..b0238473b68
--- /dev/null
+++ b/llvm/test/Transforms/LoopSimplify/indirectbr.ll
@@ -0,0 +1,83 @@
+; RUN: opt < %s -loopsimplify -lcssa -verify-loop-info -verify-dom-info -S \
+; RUN:   | grep -F {indirectbr i8* %x, \[label %L0, label %L1\]} \
+; RUN:   | count 6
+
+; LoopSimplify should not try to transform loops when indirectbr is involved.
+
+define void @entry(i8* %x) {
+entry:
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+
+L0:
+  br label %L0
+
+L1:
+  ret void
+}
+
+define void @backedge(i8* %x) {
+entry:
+  br label %L0
+
+L0:
+  br label %L1
+
+L1:
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+}
+
+define i64 @exit(i8* %x) {
+entry:
+  br label %L2
+
+L2:
+  %z = bitcast i64 0 to i64
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+
+L0:
+  br label %L2
+
+L1:
+  ret i64 %z
+}
+
+define i64 @criticalexit(i8* %x, i1 %a) {
+entry:
+  br i1 %a, label %L1, label %L2
+
+L2:
+  %z = bitcast i64 0 to i64
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+
+L0:
+  br label %L2
+
+L1:
+  %y = phi i64 [ %z, %L2 ], [ 1, %entry ]
+  ret i64 %y
+}
+
+define i64 @exit_backedge(i8* %x) {
+entry:
+  br label %L0
+
+L0:
+  %z = bitcast i64 0 to i64
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+
+L1:
+  ret i64 %z
+}
+
+define i64 @criticalexit_backedge(i8* %x, i1 %a) {
+entry:
+  br i1 %a, label %L0, label %L1
+
+L0:
+  %z = bitcast i64 0 to i64
+  indirectbr i8* %x, [ label %L0, label %L1 ]
+
+L1:
+  %y = phi i64 [ %z, %L0 ], [ 1, %entry ]
+  ret i64 %y
+}