llvm-6502/test/Transforms/DeadArgElim/keepalive.ll
Reid Kleckner 81558937d7 inalloca: Don't remove dead arguments in the presence of inalloca args
It disturbs the layout of the parameters in memory and registers,
leading to problems in the backend.

The plan for optimizing internal inalloca functions going forward is to
essentially SROA the argument memory and demote any captured arguments
(things that aren't trivially written by a load or store) to an indirect
pointer to a static alloca.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200717 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-03 20:42:49 +00:00

48 lines
1.5 KiB
LLVM

; RUN: opt < %s -deadargelim -S | FileCheck %s
%Ty = type <{ i32, i32 }>
; Check if the pass doesn't modify anything that doesn't need changing. We feed
; an unused argument to each function to lure it into changing _something_ about
; the function and then changing too much.
; This checks if the return value attributes are not removed
; CHECK: define internal zeroext i32 @test1() #0
define internal zeroext i32 @test1(i32 %DEADARG1) nounwind {
ret i32 1
}
; This checks if the struct doesn't get non-packed
; CHECK-LABEL: define internal <{ i32, i32 }> @test2(
define internal <{ i32, i32 }> @test2(i32 %DEADARG1) {
ret <{ i32, i32 }> <{ i32 1, i32 2 }>
}
; We use this external function to make sure the return values don't become dead
declare void @user(i32, <{ i32, i32 }>)
define void @caller() {
%B = call i32 @test1(i32 1)
%C = call <{ i32, i32 }> @test2(i32 2)
call void @user(i32 %B, <{ i32, i32 }> %C)
ret void
}
; We can't remove 'this' here, as that would put argmem in ecx instead of
; memory.
define internal x86_thiscallcc i32 @unused_this(i32* %this, i32* inalloca %argmem) {
%v = load i32* %argmem
ret i32 %v
}
; CHECK-LABEL: define internal x86_thiscallcc i32 @unused_this(i32* %this, i32* inalloca %argmem)
define i32 @caller2() {
%t = alloca i32
%m = alloca i32, inalloca
store i32 42, i32* %m
%v = call x86_thiscallcc i32 @unused_this(i32* %t, i32* inalloca %m)
ret i32 %v
}
; CHECK: attributes #0 = { nounwind }