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From: "ryos at sinby dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/39429] New: compiler create bad asm codes. Date: Wed, 11 Mar 2009 07:25:00 -0000 [thread overview] Message-ID: <bug-39429-17427@http.gcc.gnu.org/bugzilla/> (raw) the Compiler creates bad asm codes from following source. bool ArmGccTest::useOffScreen() { if ((mapsize - size) < 16*1024) return false; return true; } .text .align 2 .global _ZN10ArmGccTest12useOffScreenEv .type _ZN10ArmGccTest12useOffScreenEv, %function _ZN10ArmGccTest12useOffScreenEv: .fnstart .LFB2: @ Function supports interworking. @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. ldr r0, [r0, #1080] ldr r3, [r0, #1084] sub r0, r0, r3 cmp r0, #16384 movcc r0, #0 movcs r0, #1 bx lr r0 is assigned for "this". however r0 is rewritten to use "mapsize", so r3 is broken. You can see this problem by following simple c++ source. class ArmGccTest { private: unsigned int value001; .... .... .... unsigned int value109; unsigned int value10a; unsigned int value10b; unsigned int value10c; unsigned int value10d; unsigned int mapsize; unsigned int size; unsigned int value10e; bool useOffScreen(); }; -- Summary: compiler create bad asm codes. Product: gcc Version: 4.3.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: ryos at sinby dot com GCC host triplet: arm-linux, i386-linux, i386-freebsd GCC target triplet: arm-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39429
next reply other threads:[~2009-03-11 7:25 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-03-11 7:25 ryos at sinby dot com [this message] 2009-03-12 1:19 ` [Bug c++/39429] " ryos at sinby dot com 2009-03-16 22:53 ` rearnsha at gcc dot gnu dot org 2009-03-16 23:02 ` [Bug target/39429] " rearnsha at gcc dot gnu dot org 2009-07-11 20:20 ` mikpe at it dot uu dot se 2009-07-12 11:30 ` mikpe at it dot uu dot se 2009-07-12 20:51 ` ramana at gcc dot gnu dot org 2009-07-12 21:21 ` mikpe at it dot uu dot se 2009-07-12 23:58 ` mikpe at it dot uu dot se 2009-07-13 13:06 ` mikpe at it dot uu dot se 2009-07-13 13:07 ` mikpe at it dot uu dot se
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