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From: "uros at kss-loka dot si" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/28685] New: Multiple comparisons are not simplified Date: Thu, 10 Aug 2006 18:15:00 -0000 [thread overview] Message-ID: <bug-28685-1649@http.gcc.gnu.org/bugzilla/> (raw) These two testcases should produce equivalent code: int test(int a, int b) { int lt = a < b; int eq = a == b; return (lt || eq); } int test_(int a, int b) { return (a < b || a == b); } However, the optimized tree code is: ;; Function test (test) Analyzing Edge Insertions. test (a, b) { <bb 2>: return (a == b | a < b) != 0; } ;; Function test_ (test_) Analyzing Edge Insertions. test_ (a, b) { <bb 2>: return a <= b; } And the resultinh x86_64 asm is unoptimal for test() function: test: cmpl %esi, %edi sete %dl cmpl %esi, %edi setl %al orl %edx, %eax movzbl %al, %eax ret test_: xorl %eax, %eax cmpl %esi, %edi setle %al ret -- Summary: Multiple comparisons are not simplified Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: uros at kss-loka dot si GCC build triplet: x86_64-pc-linux-gnu GCC host triplet: x86_64-pc-linux-gnu GCC target triplet: x86_64-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28685
next reply other threads:[~2006-08-10 18:15 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2006-08-10 18:15 uros at kss-loka dot si [this message] 2006-08-10 18:18 ` [Bug middle-end/28685] " pinskia at gcc dot gnu dot org 2008-04-30 15:13 ` rguenth at gcc dot gnu dot org 2008-09-06 16:34 ` ubizjak at gmail dot com 2008-10-12 20:46 ` rguenth at gcc dot gnu dot org 2009-04-24 9:24 ` rguenth at gcc dot gnu dot org 2009-04-24 9:25 ` rguenth at gcc dot gnu dot org 2009-06-24 7:49 ` steven at gcc dot gnu dot org 2009-06-24 9:15 ` rguenth at gcc dot gnu dot org 2009-09-17 10:25 ` ubizjak at gmail dot com 2010-05-07 2:32 ` sandra at codesourcery dot com 2010-05-08 3:44 ` sandra at codesourcery dot com 2010-05-08 15:54 ` sandra at gcc dot gnu dot org 2010-05-24 13:22 ` sandra at codesourcery dot com 2010-05-25 8:12 ` rguenther at suse dot de 2010-06-01 2:24 ` sandra at codesourcery dot com 2010-06-08 18:16 ` sandra at gcc dot gnu dot org
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