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From: "thutt at vmware dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/16331] x86-64 inline asm register constraints insufficient WRT ABI Date: Tue, 06 Jul 2004 14:55:00 -0000 [thread overview] Message-ID: <20040706145534.7463.qmail@sourceware.org> (raw) In-Reply-To: <20040702165134.16331.thutt@vmware.com> ------- Additional Comments From thutt at vmware dot com 2004-07-06 14:55 ------- Could you reference the documentation defect number? And, I'm not sure that just the documentation is wrong; consider: extern int hokus(void); void test(void) { register int r8 asm("r8") = hokus(); register int r9 asm("r9") = 6; __asm__ __volatile__("call pokus" : : "D" (r8), "S" (2), "d" (3), "c" (4), "r" (r8), "r" (r9) ); r8 = hokus(); pokus(r8, 2, 3, 4, 5, 6); } 0000000000000000 <test>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: e8 00 00 00 00 callq 9 <test+0x9> 5: R_X86_64_PC32 hokus+0xfffffffffffffffc 9: 41 b9 06 00 00 00 mov $0x6,%r9d f: 41 b8 05 00 00 00 mov $0x5,%r8d 15: b9 04 00 00 00 mov $0x4,%ecx 1a: ba 03 00 00 00 mov $0x3,%edx 1f: be 02 00 00 00 mov $0x2,%esi 24: 44 89 c7 mov %r8d,%edi 27: b8 00 00 00 00 mov $0x0,%eax 2c: e8 00 00 00 00 callq 31 <test+0x31> 2d: R_X86_64_PC32 pokus+0xfffffffffffffffc 31: be 02 00 00 00 mov $0x2,%esi 36: ba 03 00 00 00 mov $0x3,%edx 3b: b9 04 00 00 00 mov $0x4,%ecx 40: 44 89 c7 mov %r8d,%edi 43: e8 00 00 00 00 callq 48 <test+0x48> 44: R_X86_64_PC32 pokus+0xfffffffffffffffc 48: c9 leaveq 49: c3 retq The first call of pokus() completely ignores the assigned value of the variable r8 -- instead the value '6' into it for the call. The second call assumes the the register r8 should be used for the call, but by now the wrong value has bee placed into it. Perhaps the documentation is wrong, but so is the code generated. I'm reopening. -- What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |UNCONFIRMED Resolution|INVALID | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16331
next prev parent reply other threads:[~2004-07-06 14:55 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-07-02 16:51 [Bug c/16331] New: " thutt at vmware dot com 2004-07-02 16:57 ` [Bug c/16331] " falk at debian dot org 2004-07-02 18:49 ` thutt at vmware dot com 2004-07-02 18:54 ` pinskia at gcc dot gnu dot org 2004-07-06 14:55 ` thutt at vmware dot com [this message] 2004-08-03 7:06 ` [Bug target/16331] " pinskia at gcc dot gnu dot org 2005-07-02 1:27 ` pinskia at gcc dot gnu dot org 2005-07-02 10:17 ` falk at debian dot org 2005-09-04 19:05 ` pinskia at gcc dot gnu dot org
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