https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110067
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by hongtao Liu <liuho...@gcc.gnu.org>: https://gcc.gnu.org/g:57b30f0134d9b49f7707b0c2ded6fd7686a312c8 commit r14-1510-g57b30f0134d9b49f7707b0c2ded6fd7686a312c8 Author: liuhongt <hongtao....@intel.com> Date: Thu Jun 1 12:11:24 2023 +0800 Don't try bswap + rotate when TYPE_PRECISION(n->type) > n->range. For the testcase in the PR, we have br64 = br; br64 = ((br64 << 16) & 0x000000ff00000000ull) | (br64 & 0x0000ff00ull); n->n: 0x3000000200. n->range: 32. n->type: uint64. The original code assumes n->range is same as TYPE PRECISION(n->type), and tries to rotate the mask from 0x300000200 -> 0x20300 which is incorrect. The patch fixed this bug by not trying bswap + rotate when TYPE_PRECISION(n->type) is not equal to n->range. gcc/ChangeLog: PR tree-optimization/110067 * gimple-ssa-store-merging.cc (find_bswap_or_nop): Don't try bswap + rotate when TYPE_PRECISION(n->type) > n->range. gcc/testsuite/ChangeLog: * gcc.target/i386/pr110067.c: New test.
