https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107358
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-11 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:57da0797a73f32c879bca77e121a4f55fcc57ce1 commit r11-10363-g57da0797a73f32c879bca77e121a4f55fcc57ce1 Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Oct 24 17:53:16 2022 +0200 c, c++: Fix up excess precision handling of scalar_to_vector conversion [PR107358] As mentioned earlier in the C++ excess precision support mail, the following testcase is broken with excess precision both in C and C++ (though just in C++ it was triggered in real-world code). scalar_to_vector is called in both FEs after the excess precision promotions (or stripping of EXCESS_PRECISION_EXPR), so we can then get invalid diagnostics that say float vector + float involves truncation (on ia32 from long double to float). The following patch fixes that by calling scalar_to_vector on the operands before the excess precision promotions, let scalar_to_vector just do the diagnostics (it does e.g. fold_for_warn so it will fold EXCESS_PRECISION_EXPR around REAL_CST to constants etc.) but will then do the actual conversions using the excess precision promoted operands (so say if we have vector double + (float + float) we don't actually do vector double + (float) ((long double) float + (long double) float) but vector double + (double) ((long double) float + (long double) float) 2022-10-24 Jakub Jelinek <ja...@redhat.com> PR c++/107358 gcc/c/ * c-typeck.c (build_binary_op): Pass operands before excess precision promotions to scalar_to_vector call. gcc/testsuite/ * c-c++-common/pr107358.c: New test. (cherry picked from commit 65e3274e363cb2c6bfe6b5e648916eb7696f7e2f)