https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69400
--- Comment #10 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Tue Jan 26 09:53:33 2016 New Revision: 232817 URL: https://gcc.gnu.org/viewcvs?rev=232817&root=gcc&view=rev Log: PR 69400: Invalid 128-bit modulus result As described in the PR, wi::divmod_internal was sign- rather than zero-extending a modulus result in cases where the result has fewer HWIs than the precision and the upper bit of the upper HWI was set. This patch tries to make things more robust by getting wi_pack to handle the canonicalisation step itself. Tested on x86_64-linux-gnu. I added tests to the wide-int plugin since that seemed more direct. gcc/ PR tree-optimization/69400 * wide-int.cc (wi_pack): Take the precision as argument and perform canonicalization here rather than in the callers. Use the main loop to handle all full-width HWIs. Add a zero HWI if in_len isn't a full result. (wi::divmod_internal): Update accordingly. (wi::mul_internal): Likewise. Simplify. gcc/testsuite/ PR tree-optimization/69400 * gcc.dg/plugin/wide-int_plugin.c (test_wide_int_mod_trunc): New function. (plugin_init): Call it. * gcc.dg/torture/pr69400.c: New test. Added: trunk/gcc/testsuite/gcc.dg/torture/pr69400.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.dg/plugin/wide-int_plugin.c trunk/gcc/wide-int.cc
