Add AArch64 as an experimental target.

This patch adds support for AArch64 (ARM's 64-bit architecture) to
LLVM in the "experimental" category. Currently, it won't be built
unless requested explicitly.

This initial commit should have support for:
    + Assembly of all scalar (i.e. non-NEON, non-Crypto) instructions
      (except the late addition CRC instructions).
    + CodeGen features required for C++03 and C99.
    + Compilation for the "small" memory model: code+static data <
      4GB.
    + Absolute and position-independent code.
    + GNU-style (i.e. "__thread") TLS.
    + Debugging information.

The principal omission, currently, is performance tuning.

This patch excludes the NEON support also reviewed due to an outbreak of
batshit insanity in our legal department. That will be committed soon bringing
the changes to precisely what has been approved.

Further reviews would be gratefully received.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174054 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 0 deletions

diff --git a/test/CodeGen/AArch64/flags-multiuse.ll b/test/CodeGen/AArch64/flags-multiuse.ll
new file mode 100644
index 0000000000..80be052cd9
--- /dev/null
+++ b/test/CodeGen/AArch64/flags-multiuse.ll
@@ -0,0 +1,35 @@
+; RUN: llc -march=aarch64 -verify-machineinstrs < %s | FileCheck %s
+
+; LLVM should be able to cope with multiple uses of the same flag-setting
+; instruction at different points of a routine. Either by rematerializing the
+; compare or by saving and restoring the flag register.
+
+declare void @bar()
+
+@var = global i32 0
+
+define i32 @test_multiflag(i32 %n, i32 %m, i32 %o) {
+; CHECK: test_multiflag:
+
+  %test = icmp ne i32 %n, %m
+; CHECK: cmp [[LHS:w[0-9]+]], [[RHS:w[0-9]+]]
+
+  %val = zext i1 %test to i32
+; CHECK: csinc {{[xw][0-9]+}}, {{xzr|wzr}}, {{xzr|wzr}}, eq
+
+  store i32 %val, i32* @var
+
+  call void @bar()
+; CHECK: bl bar
+
+  ; Currently, the comparison is emitted again. An MSR/MRS pair would also be
+  ; acceptable, but assuming the call preserves NZCV is not.
+  br i1 %test, label %iftrue, label %iffalse
+; CHECK: cmp [[LHS]], [[RHS]]
+; CHECK: b.eq
+
+iftrue:
+  ret i32 42
+iffalse:
+  ret i32 0
+}