Test case which should have been part of 250343

llvm-svn: 250344

1 files changed, 86 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/fast-fallthrough.ll b/llvm/test/Transforms/SimplifyCFG/fast-fallthrough.ll
new file mode 100644
index 00000000000..7c5dbe2b0ad
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/fast-fallthrough.ll
@@ -0,0 +1,86 @@
+; RUN: opt -S %s -simplifycfg | FileCheck %s
+
+define void @test(i32 %length.i, i32 %i) {
+; CHECK-LABEL: @test
+  %iplus1 = add nsw i32 %i, 1
+  %var29 = icmp slt i32 %i, %length.i
+  %var30 = icmp slt i32 %iplus1, %length.i
+; CHECK: br i1 %var30, label %in_bounds, label %next
+  br i1 %var29, label %next, label %out_of_bounds, !prof !{!"branch_weights", i32 1000, i32 0}
+
+next:
+; CHECK-LABEL: next:
+; CHECK: br i1 %var29, label %out_of_bounds2, label %out_of_bounds
+  br i1 %var30, label %in_bounds, label %out_of_bounds2, !prof !{!"branch_weights", i32 1000, i32 0}
+
+in_bounds:
+  ret void
+
+out_of_bounds:
+  call void @foo(i64 0)
+  unreachable
+
+out_of_bounds2:
+  call void @foo(i64 1)
+  unreachable
+}
+
+define void @test2(i32 %length.i, i32 %i) {
+; CHECK-LABEL: @test2
+  %var29 = icmp slt i32 %i, %length.i
+; CHECK: br i1 %var30, label %in_bounds, label %next
+  br i1 %var29, label %next, label %out_of_bounds, !prof !{!"branch_weights", i32 1000, i32 0}
+
+next:
+; CHECK-LABEL: next:
+; CHECK: br i1 %var29, label %out_of_bounds2, label %out_of_bounds
+  %iplus1 = add nsw i32 %i, 1
+  %var30 = icmp slt i32 %iplus1, %length.i
+  br i1 %var30, label %in_bounds, label %out_of_bounds2, !prof !{!"branch_weights", i32 1000, i32 0}
+
+in_bounds:
+  ret void
+
+out_of_bounds:
+  call void @foo(i64 0)
+  unreachable
+
+out_of_bounds2:
+  call void @foo(i64 1)
+  unreachable
+}
+
+; As written, this one can't trigger today.  It would require us to duplicate
+; the %val1 load down two paths and that's not implemented yet.
+define i64 @test3(i32 %length.i, i32 %i, i64* %base) {
+; CHECK-LABEL: @test3
+  %var29 = icmp slt i32 %i, %length.i
+; CHECK: br i1 %var29, label %next, label %out_of_bounds
+  br i1 %var29, label %next, label %out_of_bounds, !prof !{!"branch_weights", i32 1000, i32 0}
+
+next:
+; CHECK-LABEL: next:
+  %addr1 = getelementptr i64, i64* %base, i32 %i
+  %val1 = load i64, i64* %addr1
+  %iplus1 = add nsw i32 %i, 1
+  %var30 = icmp slt i32 %iplus1, %length.i
+; CHECK: br i1 %var30, label %in_bounds, label %out_of_bounds2
+  br i1 %var30, label %in_bounds, label %out_of_bounds2, !prof !{!"branch_weights", i32 1000, i32 0}
+
+in_bounds:
+  %addr2 = getelementptr i64, i64* %base, i32 %iplus1
+  %val2 = load i64, i64* %addr2
+  %res = sub i64 %val1, %val2
+  ret i64 %res
+
+out_of_bounds:
+  call void @foo(i64 0)
+  unreachable
+
+out_of_bounds2:
+  call void @foo(i64 %val1)
+  unreachable
+}
+
+declare void @foo(i64)
+