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From: "falk at debian dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/18577] New: [3.3 regression] variable use moved before initialization Date: Sat, 20 Nov 2004 16:30:00 -0000 [thread overview] Message-ID: <20041120163030.18577.falk@debian.org> (raw) Test case: static float tfcos12[3]; __attribute__((noinline)) double f(double x) { return x; } int g; int main(void) { int i, j; for (i = 0; i < 1; i++) tfcos12[i] = 0.5; for (i = 0; i < 1; i++) { tfcos12[i] = 0.5 * f(i); for (j = 0; j < 12; j++) g++; } return 0; } % gcc -funroll-all-loops -O2 test.c && ./a.out zsh: floating point exception (core dumped) ./a.out The reason is that the constant 0.5 is first used and then loaded: [...] cpys $f10,$f10,$f2 # use $f10 lds $f10,$LC0($1) !gprellow # before loading it [...] mult $f2,$f0,$f0 # and this FPEs This does not happen without -funroll-all-loops. Also not at -O, or with 3.4. -- Summary: [3.3 regression] variable use moved before initialization Product: gcc Version: 3.3.5 Status: UNCONFIRMED Keywords: wrong-code Severity: critical Priority: P2 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: falk at debian dot org CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: alphaev68-unknown-linux-gnu GCC host triplet: alphaev68-unknown-linux-gnu GCC target triplet: alphaev68-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18577
next reply other threads:[~2004-11-20 16:30 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-11-20 16:30 falk at debian dot org [this message] 2004-11-20 16:32 ` [Bug rtl-optimization/18577] " pinskia at gcc dot gnu dot org 2004-11-21 2:33 ` falk at debian dot org 2004-11-21 7:14 ` ebotcazou at gcc dot gnu dot org 2004-11-21 9:07 ` ebotcazou at gcc dot gnu dot org 2004-11-27 16:59 ` cvs-commit at gcc dot gnu dot org 2004-11-27 17:05 ` ebotcazou at gcc dot gnu dot org
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