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From: "roger at nextmovesoftware dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/107812] [11/12/13/14 Regression] RTL SSA forwprop introduced regression since r11-6188 Date: Mon, 29 May 2023 16:17:13 +0000 [thread overview] Message-ID: <bug-107812-4-XNyuB5uato@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-107812-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107812 Roger Sayle <roger at nextmovesoftware dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |roger at nextmovesoftware dot com --- Comment #3 from Roger Sayle <roger at nextmovesoftware dot com> --- Things are better but not perfect on trunk (GCC 14.0.0): pushl %esi pushl %ebx movl 16(%esp), %eax ; y movl 20(%esp), %ecx ; z movl 12(%esp), %edx ; x movl 4(%eax), %ebx ; y[1] movl (%eax), %esi ; y[0] movl %ebx, %eax shrdl %esi, %eax movl %eax, (%edx) popl %ebx popl %esi ret So the xorl and orl are gone, and we're down to two pushs/pops. It looks like the additional spill is just a difference in register allocation. Perhaps i386.md's *concatsidi3_3 could be cleverer (to avoid the early clobber &r when both operands are mem, and their addressing mode is sufficently simple). i.e. movl (%eax), %esi ; y[0] movl 4(%eax), %eax ; y[1] instead of movl 4(%eax), %ebx ; y[1] movl (%eax), %esi ; y[0] movl %ebx, %eax
prev parent reply other threads:[~2023-05-29 16:17 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-11-22 12:54 [Bug target/107812] New: [11/12/13 Regression] RTL SSA forwprop introduced regression jakub at gcc dot gnu.org 2022-11-22 12:54 ` [Bug target/107812] [11/12/13 Regression] RTL SSA forwprop introduced regression since r11-6188 jakub at gcc dot gnu.org 2022-11-22 14:29 ` rsandifo at gcc dot gnu.org 2022-12-01 8:36 ` jakub at gcc dot gnu.org 2023-05-29 10:07 ` [Bug target/107812] [11/12/13/14 " jakub at gcc dot gnu.org 2023-05-29 16:17 ` roger at nextmovesoftware dot com [this message]
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