1 files changed, 51 insertions, 0 deletions
diff --git a/test/Transforms/IndVarSimplify/lcssa-preservation.ll b/test/Transforms/IndVarSimplify/lcssa-preservation.ll
new file mode 100644
index 0000000000..f69c96ce02
--- /dev/null
+++ b/test/Transforms/IndVarSimplify/lcssa-preservation.ll
@@ -0,0 +1,51 @@
+; RUN: opt < %s -indvars -S | FileCheck %s
+;
+; Make sure IndVars preserves LCSSA form, especially across loop nests. 
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+
+define void @PR18642(i32 %x) {
+; CHECK-LABEL: @PR18642(
+entry:
+  br label %outer.header
+; CHECK:   br label %outer.header
+
+outer.header:
+; CHECK: outer.header:
+  %outer.iv = phi i32 [ 0, %entry ], [ %x, %outer.latch ]
+  br label %inner.header
+; CHECK:   %[[SCEV_EXPANDED:.*]] = add i32
+; CHECK:   br label %inner.header
+
+inner.header:
+; CHECK: inner.header:
+  %inner.iv = phi i32 [ undef, %outer.header ], [ %inc, %inner.latch ]
+  %cmp1 = icmp slt i32 %inner.iv, %outer.iv
+  br i1 %cmp1, label %inner.latch, label %outer.latch
+; CHECK:   br i1 {{.*}}, label %inner.latch, label %outer.latch
+
+inner.latch:
+; CHECK: inner.latch:
+  %inc = add nsw i32 %inner.iv, 1
+  %cmp2 = icmp slt i32 %inner.iv, %outer.iv
+  br i1 %cmp2, label %inner.header, label %exit
+; CHECK:   br i1 {{.*}}, label %inner.header, label %[[EXIT_FROM_INNER:.*]]
+
+outer.latch:
+; CHECK: outer.latch:
+  br i1 undef, label %outer.header, label %exit
+; CHECK:   br i1 {{.*}}, label %outer.header, label %[[EXIT_FROM_OUTER:.*]]
+
+; CHECK: [[EXIT_FROM_INNER]]:
+; CHECK-NEXT: %[[LCSSA:.*]] = phi i32 [ %[[SCEV_EXPANDED]], %inner.latch ]
+; CHECK-NEXT: br label %exit
+
+; CHECK: [[EXIT_FROM_OUTER]]:
+; CHECK-NEXT: br label %exit
+
+exit:
+; CHECK: exit:
+  %exit.phi = phi i32 [ %inc, %inner.latch ], [ undef, %outer.latch ]
+; CHECK-NEXT: phi i32 [ %[[LCSSA]], %[[EXIT_FROM_INNER]] ], [ undef, %[[EXIT_FROM_OUTER]] ]
+  ret void
+}