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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/52055] load of 64-bit pointer reads 64 bits even when only 32 are used Date: Tue, 31 Jan 2012 19:02:00 -0000 [thread overview] Message-ID: <bug-52055-4-FbruEkWSyo@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-52055-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52055 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-31 18:29:33 UTC --- Combine can already do this kind of change, as can be seen e.g. on void foo (unsigned long long *p) { asm volatile ("" : : "rm" ((unsigned) *p)); } where combine shortens the load into SImode load, but on this testcase we don't attempt to combine it, because cant_combine_insn_p on the insn with subreg says we shouldn't combine it (the src is a subreg:SI of the reg:DI initialized by the DImode memory load, but dest is hard register %eax, which has likely spilled register class). So, shell we do this kind of shortening in fwprop instead? If a MEM load has all uses subregged to a narrower mode, try to subreg it and adjust the callers?
next prev parent reply other threads:[~2012-01-31 18:29 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-01-30 19:28 [Bug target/52055] New: " jhaberman at gmail dot com 2012-01-31 11:44 ` [Bug target/52055] " rguenth at gcc dot gnu.org 2012-01-31 18:29 ` jhaberman at gmail dot com 2012-01-31 19:02 ` jakub at gcc dot gnu.org [this message] 2012-02-01 16:14 ` ebotcazou at gcc dot gnu.org 2012-02-01 16:36 ` jakub at gcc dot gnu.org 2012-02-14 5:22 ` pinskia at gcc dot gnu.org
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