https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82816
--- Comment #2 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Mon Nov 6 14:47:43 2017 New Revision: 254454 URL: https://gcc.gnu.org/viewcvs?rev=254454&root=gcc&view=rev Log: PR82816: Widening multiplies of bitfields In this PR we tried to create a widening multiply of two 3-bit numbers, but that isn't a widening multiply at the optab/rtl level, since both the input and output still have the same mode. We could trap this either in is_widening_mult_p or (as the patch does) in the routines that actually ask for an optab. The latter seemed more natural since is_widening_mult_p doesn't otherwise care about modes. 2017-11-03 Richard Sandiford <richard.sandif...@linaro.org> Alan Hayward <alan.hayw...@arm.com> David Sherwood <david.sherw...@arm.com> gcc/ PR tree-optimization/82816 * tree-ssa-math-opts.c (convert_mult_to_widen): Return false if the modes of the two types are the same. (convert_plusminus_to_widen): Likewise. gcc/testsuite/ * gcc.c-torture/compile/pr82816.c: New test. Added: trunk/gcc/testsuite/gcc.c-torture/compile/pr82816.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-ssa-math-opts.c
