1 ; RUN: llc < %s -relocation-model=pic -O2 -disable-fp-elim -o - | FileCheck %s 2 ; RUN: llc < %s -relocation-model=pic -O2 -o - | FileCheck %s 3 4 ; This test runs twice with different options regarding the frame pointer: 5 ; first the elimination is disabled, then it is enabled. The disabled case is 6 ; the "control group". 7 ; The function 'foo' below is marked with the "no-frame-pointer-elim-non-leaf" 8 ; attribute which dictates that the frame pointer should not be eliminated 9 ; unless the function is a leaf (i.e. it doesn't call any other function). 10 ; Now, 'foo' is not a leaf function, because it performs a TLS access which on 11 ; X86 ELF in PIC mode is expanded as a library call. 12 ; This call is represented with a pseudo-instruction which doesn't appear to be 13 ; a call when inspected by the analysis passes (it doesn't have the "isCall" 14 ; flag), and the ISel lowering code creating the pseudo was not informing the 15 ; MachineFrameInfo that the function contained calls. This affected the decision 16 ; whether to eliminate the frame pointer. 17 ; With the fix, the "hasCalls" flag is set in the MFI for the function whenever 18 ; a TLS access pseudo-instruction is created, so 'foo' appears to be a non-leaf 19 ; function, and the difference in the options does not affect codegen: both 20 ; versions will have a frame pointer. 21 22 ; Test that there's some frame pointer usage in 'foo'... 23 ; CHECK: foo: 24 ; CHECK: pushq %rbp 25 ; CHECK: movq %rsp, %rbp 26 ; ... and the TLS library call is also present. 27 ; CHECK: leaq x@TLSGD(%rip), %rdi 28 ; CHECK: callq __tls_get_addr@PLT 29 30 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 31 target triple = "x86_64-unknown-linux-gnu" 32 33 @x = thread_local global i32 0 34 define i32 @foo() "no-frame-pointer-elim-non-leaf" { 35 %a = load i32, i32* @x, align 4 36 ret i32 %a 37 } 38
