Add support for a preserve_most calling convention to the AArch64 backend.

This change adds a support for a preserve_most calling convention to the AArch64 backend, similar to how it was done for X86-64.

There is also a subsequent patch on top of this one to add a tail-calls support for this calling convention.

Differential Revision: http://reviews.llvm.org/D18016

llvm-svn: 263092

1 files changed, 40 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/preserve_mostcc.ll b/llvm/test/CodeGen/AArch64/preserve_mostcc.ll
new file mode 100644
index 00000000000..7f0968c8eb3
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/preserve_mostcc.ll
@@ -0,0 +1,40 @@
+; RUN: llc < %s -mtriple=arm64-apple-ios-8.0.0 | FileCheck %s
+
+declare void @standard_cc_func()
+declare preserve_mostcc void @preserve_mostcc_func()
+
+; Registers r9-r15 should be saved before the call of a function
+; with a standard calling convention.
+define preserve_mostcc void @preserve_mostcc1() nounwind {
+entry:
+;CHECK-LABEL: preserve_mostcc1
+;CHECK-NOT:   stp
+;CHECK-NOT:   str
+;CHECK:       str     x15
+;CHECK-NEXT:  stp     x14, x13,
+;CHECK-NEXT:  stp     x12, x11,
+;CHECK-NEXT:  stp     x10, x9,
+;CHECK:       bl      _standard_cc_func
+  call void @standard_cc_func()
+;CHECK:       ldp     x10, x9,
+;CHECK-NEXT:  ldp     x12, x11,
+;CHECK-NEXT:  ldp     x14, x13,
+;CHECK-NEXT:  ldr     x15
+  ret void
+}
+
+; Registers r9-r15 don't need to be saved if one
+; function with preserve_mostcc calling convention calls another
+; function with preserve_mostcc calling convention, because the
+; callee wil save these registers anyways.
+define preserve_mostcc void @preserve_mostcc2() nounwind {
+entry:
+;CHECK-LABEL: preserve_mostcc2
+;CHECK-NOT: x14
+;CHECK:     stp     x29, x30,
+;CHECK-NOT: x14
+;CHECK:     bl      _preserve_mostcc_func
+  call preserve_mostcc void @preserve_mostcc_func()
+  ret void
+}
+