test/CodeGen/Thumb/large-stack.ll

; RUN: llc < %s -mtriple=thumb-apple-ios | FileCheck %s --check-prefix=CHECK --check-prefix=ALIGN4
; RUN: llc < %s -mtriple=thumb-none-eabi | FileCheck %s --check-prefix=CHECK --check-prefix=ALIGN8
; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-apple-ios
; RUN: llvm-objdump -triple=thumbv6-apple-ios -d %t | FileCheck %s --check-prefix=CHECK --check-prefix=ALIGN4
; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-none-eabi
; RUN: llvm-objdump -triple=thumbv6-none-eabi -d %t | FileCheck %s --check-prefix=CHECK --check-prefix=ALIGN8

; Largest stack for which a single tADDspi/tSUBspi is enough
define void @test1() {
; CHECK-LABEL: test1:
; CHECK: sub sp, #508
; CHECK: add sp, #508
    %tmp = alloca [ 508 x i8 ] , align 4
    ret void
}

; Largest stack for which three tADDspi/tSUBspis are enough
define void @test100() {
; CHECK-LABEL: test100:
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; CHECK: add sp, #508
; CHECK: add sp, #508
; CHECK: add sp, #508
    %tmp = alloca [ 1524 x i8 ] , align 4
    ret void
}

; Largest stack for which three tADDspi/tSUBspis are enough
define void @test100_nofpelim() "no-frame-pointer-elim"="true" {
; CHECK-LABEL: test100_nofpelim:
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; ALIGN4: subs r4, r7, #4
; ALIGN8: subs r4, r7, #7
; ALIGN8: subs r4, #1
; CHECK: mov sp, r4
    %tmp = alloca [ 1524 x i8 ] , align 4
    ret void
}

; Smallest stack for which we use a constant pool
define void @test2() {
; CHECK-LABEL: test2:
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
    %tmp = alloca [ 1528 x i8 ] , align 4
    ret void
}

; Smallest stack for which we use a constant pool
define void @test2_nofpelim() "no-frame-pointer-elim"="true" {
; CHECK-LABEL: test2_nofpelim:
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
; ALIGN4: subs r4, r7, #4
; ALIGN8: subs r4, r7, #7
; ALIGN8: subs r4, #1
; CHECK: mov sp, r4
    %tmp = alloca [ 1528 x i8 ] , align 4
    ret void
}

define i32 @test3() {
; CHECK-LABEL: test3:
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
; CHECK: ldr [[TEMP2:r[0-7]]],
; CHECK: add [[TEMP2]], sp
; CHECK: ldr [[TEMP3:r[0-7]]],
; CHECK: add sp, [[TEMP3]]
    %retval = alloca i32, align 4
    %tmp = alloca i32, align 4
    %a = alloca [805306369 x i8], align 16
    store i32 0, i32* %tmp
    %tmp1 = load i32, i32* %tmp
    ret i32 %tmp1
}

define i32 @test3_nofpelim() "no-frame-pointer-elim"="true" {
; CHECK-LABEL: test3_nofpelim:
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
; CHECK: ldr [[TEMP2:r[0-7]]],
; CHECK: add [[TEMP2]], sp
; CHECK: subs r4, r7,
; CHECK: mov sp, r4
    %retval = alloca i32, align 4
    %tmp = alloca i32, align 4
    %a = alloca [805306369 x i8], align 16
    store i32 0, i32* %tmp
    %tmp1 = load i32, i32* %tmp
    ret i32 %tmp1
}

; Here, the adds get optimized out because they are dead, but the calculation
; of the address of stack_a is dead but not optimized out. When the address
; calculation gets expanded to two instructions, we need to avoid reading a
; dead register.
; No CHECK lines (just test for crashes), as we hope this will be optimised
; better in future.
define i32 @test4() {
entry:
  %stack_a = alloca i8, align 1
  %stack_b = alloca [256 x i32*], align 4
  %int = ptrtoint i8* %stack_a to i32
  %add = add i32 %int, 1
  br label %block2

block2:
  %add2 = add i32 %add, 1
  ret i32 0
}