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From: ehrhardt@mathematik.uni-ulm.de To: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, mark@cal005304.student.utwente.nl, nobody@gcc.gnu.org Subject: Re: optimization/8832: [<3.2,3.3> regression] traditional "asm volatile" code is illegally optimized Date: Fri, 06 Dec 2002 04:11:00 -0000 [thread overview] Message-ID: <20021206121108.3376.qmail@sources.redhat.com> (raw) Old Synopsis: "asm volatile" code is removed New Synopsis: [<3.2,3.3> regression] traditional "asm volatile" code is illegally optimized State-Changed-From-To: open->analyzed State-Changed-By: cae State-Changed-When: Fri Dec 6 04:11:08 2002 State-Changed-Why: I can confirm this with 3.3 on sparc, i.e. it isn't arch independant. These two pieces of code produce the same assembler output (except for label names) which looks like a bug to me. 3.2.1-prerelease is even worse: It completly eliminates two of the volatile asm statements. Comile with -O3 -S Priority high because this is a regression from 2.95.3 ----------------- variant 1 ------------------------- void f (int v) { asm volatile ("blah p0, p1" ); if (v&7) { asm volatile ("blub p0, p1" ); } asm volatile ("foo p0, p1"); if (v&7) { asm volatile ("bar p0, p1" ); } asm volatile ("baz p0, p1" ); } ----------------- end -------------------------- ----------------- variant 2 ------------------------- void f (int v) { asm volatile ("blah p0, p1" ); if (v&7) { asm volatile ("blub p0, p1" ); asm volatile ("foo p0, p1"); asm volatile ("bar p0, p1" ); } asm volatile ("baz p0, p1" ); } ----------------- end -------------------------- http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8832
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