[FastISel][AArch64] Add custom lowering for GEPs.

This is mostly a copy of the existing FastISel GEP code, but on AArch64 we bail
out even for simple cases, because the standard fastEmit functions don't cover
MUL and ADD is lowered inefficientily.

llvm-svn: 219726

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/fast-isel-gep.ll b/llvm/test/CodeGen/AArch64/fast-isel-gep.ll
new file mode 100644
index 00000000000..d72019801ba
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/fast-isel-gep.ll
@@ -0,0 +1,18 @@
+; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -fast-isel-abort -verify-machineinstrs < %s | FileCheck %s
+
+%struct.foo = type { i32, i64, float, double }
+
+define double* @test_struct(%struct.foo* %f) {
+; CHECK-LABEL: test_struct
+; CHECK:       add x0, x0, #24
+  %1 = getelementptr inbounds %struct.foo* %f, i64 0, i32 3
+  ret double* %1
+}
+
+define i32* @test_array(i32* %a, i64 %i) {
+; CHECK-LABEL: test_array
+; CHECK:       orr [[REG:x[0-9]+]], xzr, #0x4
+; CHECK-NEXT:  madd  x0, x1, [[REG]], x0
+  %1 = getelementptr inbounds i32* %a, i64 %i
+  ret i32* %1
+}