1 files changed, 29 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopUnroll/partial-unroll-const-bounds.ll b/llvm/test/Transforms/LoopUnroll/partial-unroll-const-bounds.ll
new file mode 100644
index 00000000000..04bee115c2b
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/partial-unroll-const-bounds.ll
@@ -0,0 +1,29 @@
+; RUN: opt < %s -S -unroll-threshold=20 -loop-unroll -unroll-allow-partial | FileCheck %s
+
+; The Loop TripCount is 9. However unroll factors 3 or 9 exceed given threshold.
+; The test checks that we choose a smaller, power-of-two, unroll count and do not give up on unrolling.
+
+; CHECK: for.body:
+; CHECK: store
+; CHECK: for.body.1:
+; CHECK: store
+
+define void @foo(i32* nocapture %a, i32* nocapture readonly %b) nounwind uwtable {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 1, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
+  %ld = load i32, i32* %arrayidx, align 4
+  %idxprom1 = sext i32 %ld to i64
+  %arrayidx2 = getelementptr inbounds i32, i32* %a, i64 %idxprom1
+  %st = trunc i64 %indvars.iv to i32
+  store i32 %st, i32* %arrayidx2, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 10
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}