1 files changed, 29 insertions, 0 deletions
diff --git a/test/CodeGen/AArch64/arm64-dagcombiner-dead-indexed-load.ll b/test/CodeGen/AArch64/arm64-dagcombiner-dead-indexed-load.ll
new file mode 100644
index 0000000000..2cf0135732
--- /dev/null
+++ b/test/CodeGen/AArch64/arm64-dagcombiner-dead-indexed-load.ll
@@ -0,0 +1,29 @@
+; RUN: llc -mcpu=cyclone < %s | FileCheck %s
+
+target datalayout = "e-i64:64-n32:64-S128"
+target triple = "arm64-apple-ios"
+
+%"struct.SU" = type { i32, %"struct.SU"*, i32*, i32, i32, %"struct.BO", i32, [5 x i8] }
+%"struct.BO" = type { %"struct.RE" }
+
+%"struct.RE" = type { i32, i32, i32, i32 }
+
+; This is a read-modify-write of some bifields combined into an i48.  It gets
+; legalized into i32 and i16 accesses.  Only a single store of zero to the low
+; i32 part should be live.
+
+; CHECK-LABEL: test:
+; CHECK-NOT: ldr
+; CHECK: str wzr
+; CHECK-NOT: str
+define void @test(%"struct.SU"* nocapture %su) {
+entry:
+  %r1 = getelementptr inbounds %"struct.SU"* %su, i64 1, i32 5
+  %r2 = bitcast %"struct.BO"* %r1 to i48*
+  %r3 = load i48* %r2, align 8
+  %r4 = and i48 %r3, -4294967296
+  %r5 = or i48 0, %r4
+  store i48 %r5, i48* %r2, align 8
+
+  ret void
+}