Fix a trip-count overflow issue in LoopUnroll.
Currently LoopUnroll generates a prologue loop before the main loop
body to execute first N%UnrollFactor iterations. Also, this loop is
used if trip-count can overflow - it's determined by a runtime check.
However, we've been mistakenly optimizing this loop to a linear code for
UnrollFactor = 2, not taking into account that it also serves as a safe
version of the loop if its trip-count overflows.
llvm-svn: 222451
diff --git a/llvm/test/Transforms/LoopUnroll/runtime-loop1.ll b/llvm/test/Transforms/LoopUnroll/runtime-loop1.ll
index 5ff75e3..38b4f32 100644
--- a/llvm/test/Transforms/LoopUnroll/runtime-loop1.ll
+++ b/llvm/test/Transforms/LoopUnroll/runtime-loop1.ll
@@ -3,7 +3,7 @@
; This tests that setting the unroll count works
; CHECK: for.body.prol:
-; CHECK: br label %for.body.preheader.split
+; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label %for.body.preheader.split
; CHECK: for.body:
; CHECK: br i1 %exitcond.1, label %for.end.loopexit.unr-lcssa, label %for.body
; CHECK-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label %for.body