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From: "carrot at google dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/44374] New: Hoist same instructions in different branches Date: Wed, 02 Jun 2010 08:20:00 -0000 [thread overview] Message-ID: <bug-44374-17659@http.gcc.gnu.org/bugzilla/> (raw) Compile the attached test case with options -march=armv7-a -mthumb -Os, this code snippet if (native) dlmalloc_walk_heap(heap_chunk_callback, (void *)&ctx); else dvmHeapSourceWalk(heap_chunk_callback, (void *)&ctx); is compiled to: cbz r5, .L2 ldr r0, .L4 // A mov r1, sp // B bl dlmalloc_walk_heap b .L1 .L2: ldr r0, .L4 // C mov r1, sp // D bl dvmHeapSourceWalk .L1: add sp, sp, #44 pop {r4, r5, pc} .L5: .align 2 .L4: .word heap_chunk_callback Note that instructions AB are equal to instructions CD, if we move the previous conditional branch after B, then CD can be removed. Option -O2 and target arm have the same problem. Which pass should do this optimization? pass_rtl_hoist? -- Summary: Hoist same instructions in different branches Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization 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=44374
next reply other threads:[~2010-06-02 8:20 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-06-02 8:20 carrot at google dot com [this message] 2010-06-02 8:21 ` [Bug rtl-optimization/44374] " carrot at google dot com 2010-06-02 8:54 ` steven at gcc dot gnu dot org 2010-09-23 10:05 ` bernds at gcc dot gnu dot org 2010-09-23 10:08 ` bernds at gcc dot gnu dot org
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