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From: "carrot at google dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/40835] New: redundant comparison instruction Date: Thu, 23 Jul 2009 08:38:00 -0000 [thread overview] Message-ID: <bug-40835-17659@http.gcc.gnu.org/bugzilla/> (raw) Compile the following code with options -Os -mthumb -march=armv5te int bar(); void goo(int, int); void foo() { int v = bar(); if (v == 0) return; goo(1, v); } Gcc generates: push {r3, lr} bl bar mov r1, r0 cmp r0, #0 // * beq .L1 mov r0, #1 bl goo .L1: @ sp needed for prologue pop {r3, pc} The compare instruction is redundant since the previous move instruction has already set the condition code according to the value of r0. -- Summary: redundant comparison instruction Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: carrot at google dot com GCC build triplet: i686-linux GCC host triplet: i686-linux GCC target triplet: arm-eabi http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40835
next reply other threads:[~2009-07-23 8:38 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-07-23 8:38 carrot at google dot com [this message] 2009-07-23 8:38 ` [Bug target/40835] " carrot at google dot com 2009-07-24 2:11 ` carrot at google dot com 2009-07-24 7:00 ` steven at gcc dot gnu dot org 2009-07-24 7:38 ` carrot at google dot com 2009-07-24 8:25 ` steven at gcc dot gnu dot org 2009-07-24 8:49 ` steven at gcc dot gnu dot org 2009-07-24 14:09 ` rearnsha at gcc dot gnu dot org 2009-11-04 14:10 ` rearnsha at gcc dot gnu dot org 2009-11-23 8:51 ` carrot at google dot com
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