------- Additional Comments From zhangjie at magima dot com dot cn 2004-07-30 06:50 ------- I believe the bug is caused by a problem in alias analysis. At the end of alias1, TMT.9 might alias x and bits:
Variable: TMT.9, UID 13, is global, call clobbered, may aliases: { x bits } and was call-clobbered. However, add_may_alias () failed to set x call-clobbered: Variable: x, UID 1, is an alias tag, default def: x_9 This inconsistency resulted in the bug. At the one hand, add_stmt_operand () added x as a V_MAY_DEF when renaming variables at the end of alias1 because x wass an alias of TMT.9 and TMT.9 was call-clobbered. At the other hand, tailr1 pass failed to recognize that x was an alias of a call-clobbered variable. It was executed. This patch will make the call-clobbered information consistent and fix this bug. 2004-07-30 Jie Zhang <[EMAIL PROTECTED]> PR tree-optimization/16225 * tree-ssa-alias.c (add_may_alias): If 'alias' is call-clobbered, so are 'var' and its aliases. *** tree-ssa-alias.c.old 2004-07-24 09:05:44.000000000 +0800 --- tree-ssa-alias.c 2004-07-30 13:13:06.000000000 +0800 *************** add_may_alias (tree var, tree alias) *** 1678,1686 **** if (is_call_clobbered (var)) mark_call_clobbered (alias); ! /* Likewise. If ALIAS is call-clobbered, so is VAR. */ else if (is_call_clobbered (alias)) ! mark_call_clobbered (var); VARRAY_PUSH_TREE (v_ann->may_aliases, alias); a_ann->is_alias_tag = 1; --- 1678,1690 ---- if (is_call_clobbered (var)) mark_call_clobbered (alias); ! /* Likewise. If ALIAS is call-clobbered, so are VAR and its aliases. */ else if (is_call_clobbered (alias)) ! { ! mark_call_clobbered (var); ! for (i = 0; i < VARRAY_ACTIVE_SIZE (v_ann->may_aliases); i++) ! mark_call_clobbered (VARRAY_TREE (v_ann->may_aliases, i)); ! } VARRAY_PUSH_TREE (v_ann->may_aliases, alias); a_ann->is_alias_tag = 1; -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16225 ------- You are receiving this mail because: ------- You reported the bug, or are watching the reporter.