Compile the following with -O1 in 4.0 branch. Don't be in a hurry; I killed it after 10 minutes, but I'm told it goes for hours. With -fno-ivopts added it completes almost immediately. The recursion is in instantiate_parameters_1 called from simple_iv.
/**********************************************************************/ extern int Loop1Max,Loop2Max; void bar(int a, int b, int c); void foo(int parm); /**********************************************************************/ #define x7(x) x;x;x;x;x;x;x #define REPL(x) x7(x);x7(x);x7(x);x7(x);x7(x);x7(x) // 6 * 7 = 42 (0.06 seconds compile-time for GCC 3.3, 1 year for GCC 4.0) // Changing REPL from 42 to 21 will reduce GCC 4.0 compile-time to 20 sec onds. /**********************************************************************/ void foo(int parm) { register int x,y; register int a,b,c; a = b = c = parm; for (y=0; y<Loop2Max; ++y) { for (x=0; x<Loop1Max; ++x) { REPL ( a = c * a; b = a * b; c = parm - a; ); } } bar(a,b,c); return; } /**********************************************************************/ -- Summary: Pseudo-infinite recursion in ivopts Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dalej at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: powerpc-apple-darwin8.0.0 GCC host triplet: powerpc-apple-darwin8.0.0 GCC target triplet: powerpc-apple-darwin8.0.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20803