llvm/test/CodeGen/AArch64/tailcall-ccmismatch.ll
Matthias Braun bac1dd9d54 ARM, AArch64, X86: Check preserved registers for tail calls.
We can only perform a tail call to a callee that preserves all the
registers that the caller needs to preserve.

This situation happens with calling conventions like preserver_mostcc or
cxx_fast_tls. It was explicitely handled for fast_tls and failing for
preserve_most. This patch generalizes the check to any calling
convention.

Related to rdar://24207743

Differential Revision: http://reviews.llvm.org/D18680

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265329 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-04 18:56:13 +00:00

25 lines
808 B
LLVM

; RUN: llc -o - %s | FileCheck %s
target triple="aarch64--"
declare void @somefunc()
define preserve_mostcc void @test_ccmismatch_notail() {
; Ensure that no tail call is used here, as the called function somefunc does
; not preserve enough registers for preserve_mostcc.
; CHECK-LABEL: test_ccmismatch_notail:
; CHECK-NOT: b somefunc
; CHECK: bl somefunc
tail call void @somefunc()
ret void
}
declare preserve_mostcc void @some_preserve_most_func()
define void @test_ccmismatch_tail() {
; We can perform a tail call here, because some_preserve_most_func preserves
; all registers necessary for test_ccmismatch_tail.
; CHECK-LABEL: test_ccmismatch_tail:
; CHECK-NOT: bl some_preserve_most_func
; CHECK: b some_preserve_most_func
tail call preserve_mostcc void @some_preserve_most_func()
ret void
}