llvm/test/CodeGen/ARM/2012-10-18-PR14099-ByvalFrameAddress.ll
Tim Northover 52f83a9ab3 ARM: simplify and extend byval handling
The main issue being fixed here is that APCS targets handling a "byval align N"
parameter with N > 4 were miscounting what objects were where on the stack,
leading to FrameLowering setting the frame pointer incorrectly and clobbering
the stack.

But byval handling had grown over many years, and had multiple layers of cruft
trying to compensate for each other and calculate padding correctly. This only
really needs to be done once, in the HandleByVal function. Elsewhere should
just do what it's told by that call.

I also stripped out unnecessary APCS/AAPCS distinctions (now that Clang emits
byvals with the correct C ABI alignment), which simplified HandleByVal.

rdar://20095672

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231959 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-11 18:54:22 +00:00

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LLVM

; RUN: llc < %s -mtriple=armv7-linux-gnueabi | FileCheck %s
%struct.s = type { [4 x i32] }
@v = constant %struct.s zeroinitializer;
declare void @f(%struct.s* %p);
; CHECK-LABEL: t:
define void @t(i32 %a, %struct.s* byval %s) nounwind {
entry:
; Here we need to only check proper start address of restored %s argument.
; CHECK: sub sp, sp, #12
; CHECK: push {r11, lr}
; CHECK: sub sp, sp, #4
; CHECK: add r0, sp, #12
; CHECK: stm r0, {r1, r2, r3}
; CHECK: add r0, sp, #12
; CHECK-NEXT: bl f
call void @f(%struct.s* %s)
ret void
}
; CHECK-LABEL: caller:
define void @caller() {
; CHECK: ldm r0, {r1, r2, r3}
call void @t(i32 0, %struct.s* @v);
ret void
}