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 30target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 31target triple = "x86_64-unknown-linux-gnu" 32 33@x = thread_local global i32 0 34define i32 @foo() "no-frame-pointer-elim-non-leaf" { 35 %a = load i32, i32* @x, align 4 36 ret i32 %a 37} 38