llvm-6502/test/CodeGen/Thumb/large-stack.ll
Evan Cheng ab5c703fdb Fix epilogue codegen to avoid leaving the stack pointer in an invalid
state. Previously Thumb2 would restore sp from fp like this:
mov sp, r7
sub, sp, #4
If an interrupt is taken after the 'mov' but before the 'sub', callee-saved
registers might be clobbered by the interrupt handler. Instead, try
restoring directly from sp:
add sp, #4
Or, if necessary (with VLA, etc.) use a scratch register to compute sp and
then restore it:
sub.w r4, r7, #8
mov sp, r7
rdar://8465407


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119977 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-22 18:12:04 +00:00

36 lines
733 B
LLVM

; RUN: llc < %s -mtriple=thumb-apple-darwin | FileCheck %s
define void @test1() {
; CHECK: test1:
; CHECK: sub sp, #256
; CHECK: add sp, #256
%tmp = alloca [ 64 x i32 ] , align 4
ret void
}
define void @test2() {
; CHECK: test2:
; CHECK: ldr r0, LCPI
; CHECK: add sp, r0
; CHECK: subs r4, r7, #4
; CHECK: mov sp, r4
%tmp = alloca [ 4168 x i8 ] , align 4
ret void
}
define i32 @test3() {
; CHECK: test3:
; CHECK: ldr r2, LCPI
; CHECK: add sp, r2
; CHECK: ldr r1, LCPI
; CHECK: add r1, sp
; CHECK: subs r4, r7, #4
; 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* %tmp
ret i32 %tmp1
}