[AArch64] Add a regression test for the load store optimizer.

We have a couple of regression tests for load/store pairing, but (to my knowledge) there are no regression tests for the load/store + add/sub folding.

As a first step towards increased test coverage of this area, this commit adds a test for one instance of a load + add to pre-indexed load transformation.

llvm-svn: 209618

diff --git a/llvm/test/CodeGen/AArch64/ldst-opt.ll b/llvm/test/CodeGen/AArch64/ldst-opt.ll
new file mode 100644 (file)
index 0000000..79c18ca
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ldst-opt.ll
@@ -0,0 +1,31 @@
+; RUN: llc -mtriple=aarch64-linux-gnu -verify-machineinstrs -o - %s | FileCheck %s
+
+; This file contains tests for the AArch64 load/store optimizer.
+
+%struct.A = type { %struct.B, %struct.C }
+%struct.B = type { i8*, i8*, i8*, i8* }
+%struct.C = type { i32, i32 }
+
+; Check the following transform:
+;
+; ldr w1, [x0, #32]
+;  ...
+; add x0, x0, #32
+;  ->
+; ldr w1, [x0, #32]!
+ 
+define void @foo(%struct.A* %ptr) nounwind {
+; CHECK-LABEL: foo
+; CHECK: ldr w{{[0-9]+}}, [x{{[0-9]+}}, #32]!
+entry:
+  %a = getelementptr inbounds %struct.A* %ptr, i64 0, i32 1, i32 0
+  %add = load i32* %a, align 4
+  br label %bar
+bar:
+  %c = getelementptr inbounds %struct.A* %ptr, i64 0, i32 1
+  tail call void @bar(%struct.C* %c, i32 %add) 
+  ret void
+}
+
+declare void @bar(%struct.C*, i32)
+