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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/53802] Spurious 'may be used uninitialized' related to shifts Date: Fri, 29 Jun 2012 09:57:00 -0000 [thread overview] Message-ID: <bug-53802-4-oATH2Tlmmy@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-53802-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53802 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Status|UNCONFIRMED |NEW Last reconfirmed| |2012-06-29 Ever Confirmed|0 |1 --- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-29 09:57:17 UTC --- Confirmed. Reason is a missed "jump-threading" (peeling off one iteration): <bb 2>: <bb 3>: # number_59 = PHI <number_7(6), 4294967295(2)> # buf$2_60 = PHI <buf$2_44(6), buf$2_51(D)(2)> # buf$3_61 = PHI <buf$3_2(6), buf$3_52(D)(2)> # buf$4_64 = PHI <buf$4_6(6), buf$4_53(D)(2)> # buf$1_65 = PHI <buf$1_46(6), buf$1_50(D)(2)> if (number_59 == 0) goto <bb 5>; else goto <bb 4>; <bb 4>: D.2247_18 = number_59 >> 24; buf$1_19 = (unsigned char) D.2247_18; D.2245_20 = number_59 >> 16; buf$2_21 = (unsigned char) D.2245_20; D.2243_22 = number_59 >> 8; buf$3_23 = (unsigned char) D.2243_22; buf$4_24 = (unsigned char) number_59; <bb 5>: # buf$1_46 = PHI <buf$1_19(4), buf$1_65(3)> # buf$2_44 = PHI <buf$2_21(4), buf$2_60(3)> # buf$3_2 = PHI <buf$3_23(4), buf$3_61(3)> # buf$4_6 = PHI <buf$4_24(4), buf$4_64(3)> D.2257_29 = (unsigned int) buf$1_46; so we decide there is a path from entry to BB 5 where buf$1_46 is not initialized.
next prev parent reply other threads:[~2012-06-29 9:57 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-06-29 9:02 [Bug tree-optimization/53802] New: " lukeocamden at gmail dot com 2012-06-29 9:57 ` rguenth at gcc dot gnu.org [this message] 2014-02-03 18:31 ` [Bug tree-optimization/53802] " lukeocamden at gmail dot com
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