https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98640
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:268b54382e5248ee1a5e3f4a0841358e03290d17 commit r10-9407-g268b54382e5248ee1a5e3f4a0841358e03290d17 Author: Richard Biener <rguent...@suse.de> Date: Wed Jan 13 09:43:52 2021 +0100 tree-optimization/98640 - fix bogus sign-extension with VN VN tried to express a sign extension from int to long of a trucated quantity with a plain conversion but that loses the truncation. Since there's no single operand doing truncate plus sign extend (there was a proposed SEXT_EXPR to do that at some point mapping to RTL sign_extract) don't bother to appropriately model this with two ops (which the VN insert machinery doesn't handle and which is unlikely to CSE fully). 2021-01-13 Richard Biener <rguent...@suse.de> PR tree-optimization/98640 * tree-ssa-sccvn.c (visit_nary_op): Do not try to handle plus or minus from a truncated operand to be sign-extended. * gcc.dg/torture/pr98640.c: New testcase. (cherry picked from commit ffd28c265e6d611983cd27e9332dc799039a3f04)
