Hi, Attached please fined the updated patch. Cheers, Felix
On Tue, Sep 23, 2014 at 10:48 AM, Yangfei (Felix) <felix.y...@huawei.com> wrote: >> On 09/22/14 08:40, Felix Yang wrote: >> > Hi, >> > >> > I find that update_equiv_regs in ira.c sets the wrong EQUIV >> > reg-note for pseudo with more than one definiton in certain situation. >> > Here is a simplified RTL snippet after this function finishs handling: >> > >> > (insn 77 37 78 2 (set (reg:SI 171) >> > (const_int 0 [0])) ticket151.c:33 52 {movsi_internal_dsp} >> > (expr_list:REG_EQUAL (const_int 0 [0]) >> > (nil))) >> > >> > ...... >> > >> > (insn 79 50 53 2 (set (mem/c:SI (reg/f:SI 136) [2 g_728+0 S4 A64]) >> > (reg:SI 171)) ticket151.c:33 52 {movsi_internal_dsp} >> > (expr_list:REG_DEAD (reg:SI 171) >> > (nil))) >> > (insn 53 79 54 2 (set (mem/c:SI (reg/f:SI 162) [4 g_163+0 S4 A32]) >> > (reg:SI 163)) 52 {movsi_internal_dsp} >> > (expr_list:REG_DEAD (reg:SI 163) >> > (expr_list:REG_DEAD (reg/f:SI 162) >> > (nil)))) >> > (insn 54 53 14 2 (set (reg:SI 171) >> > (mem/u/c:SI (symbol_ref/u:SI ("*.LC8") [flags 0x2]) [4 S4 >> > A32])) ticket151.c:49 52 {movsi_internal_dsp} >> > (expr_list:REG_EQUIV (mem/u/c:SI (symbol_ref/u:SI ("*.LC8") >> > [flags 0x2]) [4 S4 A32]) >> > (expr_list:REG_EQUAL (mem/u/c:SI (symbol_ref/u:SI ("*.LC8") >> > [flags 0x2]) [4 S4 A32]) >> > (nil)))) >> > >> > >> > The REG_EQUIV of insn 54 is not correct as pseudo 171 is defined >> > in insn 77 with a differerent value. >> > This may causes reload replacing pseudo 171 with mem/u/c:SI >> > (symbol_ref/u:SI ("*.LC8"), which is wrong. >> > A proposed patch for this issue, please comment: >> Is it possible it's the conditional just above this one that is incorrect? >> >> if (DF_REG_DEF_COUNT (regno) != 1 >> && (! note >> || rtx_varies_p (XEXP (note, 0), 0) >> || (reg_equiv[regno].replacement >> && ! rtx_equal_p (XEXP (note, 0), >> >> reg_equiv[regno].replacement)))) >> { >> no_equiv (dest, set, NULL); >> continue; >> } >> >> >> ISTM the only time a multiply-set register can have a valid REG_EQUIV note >> is if >> each and every assignment to that pseudo has the same RHS. >> >> Jeff > > > Thanks Jeff. Yes, I agree that this is a better place to consider. I am > thinking of a better way to fix this. > > Vladimir, can you shed light on this and give me some suggestions? Thank you. >