large-stack.ll | Explore in Territory

; RUN: llc < %s -mtriple=thumb-apple-ios | FileCheck %s --check-prefix=CHECK
; RUN: llc < %s -mtriple=thumb-none-eabi | FileCheck %s --check-prefix=CHECK
; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-apple-ios
; RUN: llvm-objdump --no-print-imm-hex --triple=thumbv6-apple-ios -d %t | FileCheck %s --check-prefix=CHECK
; RUN: llc < %s -o %t -filetype=obj -mtriple=thumbv6-none-eabi
; RUN: llvm-objdump --no-print-imm-hex --triple=thumbv6-none-eabi -d %t | FileCheck %s --check-prefix=CHECK

; 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() "frame-pointer"="all" {
; CHECK-LABEL: test100_nofpelim{{>?}}:
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; CHECK: sub sp, #508
; CHECK: subs [[SCRATCH:r[0-7]]], r7, #7
; CHECK: subs [[SCRATCH]], #1
; CHECK: mov sp, [[SCRATCH]]
; CHECK: pop
; CHECK-SAME: [[SCRATCH]]
    %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() "frame-pointer"="all" {
; CHECK-LABEL: test2_nofpelim{{>?}}:
; CHECK: ldr [[TEMP:r[0-7]]],
; CHECK: add sp, [[TEMP]]
; CHECK: subs [[SCRATCH:r[0-7]]], r7, #7
; CHECK: subs [[SCRATCH]], #1
; CHECK: mov sp, [[SCRATCH]]
; CHECK: pop
; CHECK-SAME: [[SCRATCH]]
    %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 4
    store i32 0, ptr %tmp
    %tmp1 = load i32, ptr %tmp
    ret i32 %tmp1
}

define i32 @test3_nofpelim() "frame-pointer"="all" {
; 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 [[SCRATCH:r[0-7]]], r7,
; CHECK: mov sp, [[SCRATCH]]
; CHECK: pop
; CHECK-SAME: [[SCRATCH]]
    %retval = alloca i32, align 4
    %tmp = alloca i32, align 4
    %a = alloca [805306369 x i8], align 8
    store i32 0, ptr %tmp
    %tmp1 = load i32, ptr %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 ptr], align 4
  %int = ptrtoint ptr %stack_a to i32
  %add = add i32 %int, 1
  br label %block2

block2:
  %add2 = add i32 %add, 1
  ret i32 0
}
llvm/llvm/test/CodeGen/Thumb/large-stack.ll
