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[Bug rtl-optimization/69008] gcc emits unneeded memory access when passing trivial structs by value (ARM)
- From: "michael.collison at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 17 May 2016 18:33:42 +0000
- Subject: [Bug rtl-optimization/69008] gcc emits unneeded memory access when passing trivial structs by value (ARM)
- Auto-submitted: auto-generated
- References: <bug-69008-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69008
Michael Collison <michael.collison at linaro dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|target |rtl-optimization
--- Comment #3 from Michael Collison <michael.collison at linaro dot org> ---
Changed to component rtl optimization. Occurs on other targets as well. On
MIPS, for example, generates two redundant store to memory at -O2:
(insn 5 23 6 (set (mem/c:SI (reg/f:SI 29 $sp) [1 t+0 S4 A32])
(reg:SI 4 $4)) bugzilla_69008.c:7 310 {*movsi_internal}
(nil))
(insn 6 5 18 (set (mem/c:SI (plus:SI (reg/f:SI 29 $sp)
(const_int 4 [0x4])) [1 t+4 S4 A32])
(reg:SI 5 $5)) bugzilla_69008.c:7 310 {*movsi_internal}
(nil))
(insn 18 6 30 (use (reg/i:SI 2 $2)) bugzilla_69008.c:9 -1
(nil))
(note 30 18 27 NOTE_INSN_EPILOGUE_BEG)
(insn 27 30 32 (clobber (reg:SI 28 $28)) bugzilla_69008.c:9 -1
(nil))
(insn 32 27 29 (sequence [
(jump_insn 28 27 17 (simple_return) bugzilla_69008.c:9 629
{*simple_return}
(nil)
-> simple_return)
(insn 17 28 29 (set (reg/i:SI 2 $2)
(plus:SI (reg:SI 4 $4)
(reg:SI 5 $5))) 13 {*addsi3}
(nil))
]) bugzilla_69008.c:9 -1
(nil))