1 files changed, 59 insertions, 0 deletions
diff --git a/llvm/test/Transforms/GVN/invariant.start.ll b/llvm/test/Transforms/GVN/invariant.start.ll
new file mode 100644
index 00000000000..25f7798279d
--- /dev/null
+++ b/llvm/test/Transforms/GVN/invariant.start.ll
@@ -0,0 +1,59 @@
+; Test to make sure llvm.invariant.start calls are not treated as clobbers.
+; RUN: opt < %s -gvn -S | FileCheck %s
+
+
+declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) nounwind readonly
+declare void @llvm.invariant.end.p0i8({}*, i64, i8* nocapture) nounwind
+
+; We forward store to the load across the invariant.start intrinsic
+define i8 @forward_store() {
+; CHECK-LABEL: @forward_store
+; CHECK: call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+; CHECK-NOT: load
+; CHECK: ret i8 0
+  %a = alloca i8
+  store i8 0, i8* %a
+  %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+  %r = load i8, i8* %a
+  ret i8 %r
+}
+
+declare i8 @dummy(i8* nocapture) nounwind readonly
+
+; We forward store to the load in the non-local analysis case,
+; i.e. invariant.start is in another basic block.
+define i8 @forward_store_nonlocal(i1 %cond) {
+; CHECK-LABEL: forward_store_nonlocal
+; CHECK: call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+; CHECK: ret i8 0
+; CHECK: ret i8 %val
+  %a = alloca i8
+  store i8 0, i8* %a
+  %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+  br i1 %cond, label %loadblock, label %exit
+
+loadblock:
+  %r = load i8, i8* %a
+  ret i8 %r
+
+exit:
+  %val = call i8 @dummy(i8* %a)
+  ret i8 %val
+}
+
+; We should not value forward %foo to the invariant.end corresponding to %bar.
+define i8 @forward_store1() {
+; CHECK-LABEL: forward_store1
+; CHECK: %foo = call {}* @llvm.invariant.start.p0i8
+; CHECK-NOT: load
+; CHECK: %bar = call {}* @llvm.invariant.start.p0i8
+; CHECK: call void @llvm.invariant.end.p0i8({}* %bar, i64 1, i8* %a)
+; CHECK: ret i8 0
+  %a = alloca i8
+  store i8 0, i8* %a
+  %foo = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+  %r = load i8, i8* %a
+  %bar = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %a)
+  call void @llvm.invariant.end.p0i8({}* %bar, i64 1, i8* %a)
+  ret i8 %r
+}