https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113705
--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:a8f335ccb61bf6105192a4197ef2d84900614dc1 commit r14-8742-ga8f335ccb61bf6105192a4197ef2d84900614dc1 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Feb 2 11:25:13 2024 +0100 tree-ssa-math-opts: Fix is_widening_mult_rhs_p - unbreak bootstrap [PR113705] On Tue, Jan 30, 2024 at 07:33:10AM -0000, Roger Sayle wrote: + wide_int bits = wide_int::from (tree_nonzero_bits (rhs), + prec, + TYPE_SIGN (TREE_TYPE (rhs))); ... > + if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR > + && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST > + && wi::to_wide (gimple_assign_rhs2 (stmt)) > + == wi::mask (hprec, false, prec)) This change broke bootstrap on aarch64-linux. The problem can be seen even on the reduced testcase. The IL on the unreduced testcase before widening_mul has: # val_583 = PHI <val_26(13), val_164(40)> ... pretmp_266 = MEM[(const struct wide_int_storage *)&D.160657].len; _264 = pretmp_266 & 65535; ... _176 = (sizetype) val_583; _439 = (sizetype) _264; _284 = _439 * 8; _115 = _176 + _284; where 583/266/264 have unsigned int type and 176/439/284/115 have sizetype. widening_mul first turns that into: # val_583 = PHI <val_26(13), val_164(40)> ... pretmp_266 = MEM[(const struct wide_int_storage *)&D.160657].len; _264 = pretmp_266 & 65535; ... _176 = (sizetype) val_583; _439 = (sizetype) _264; _284 = _264 w* 8; _115 = _176 + _284; and then is_widening_mult_rhs_p is called, with type sizetype (64-bit), rhs _264, hprec 32 and prec 64. Now tree_nonzero_bits (rhs) is 65535, so bits is 64-bit wide_int 65535, stmt is BIT_AND_EXPR, but we ICE on the wi::to_wide (gimple_assign_rhs2 (stmt)) == wi::mask (hprec, false, prec) comparison because wi::to_wide on gimple_assign_rhs2 (stmt) - unsigned int 65535 gives 32-bit wide_int 65535, while wi::mask (hprec, false, prec) gives 64-bit wide_int 0xffffffff and comparison between different precision wide_ints is forbidden. The following patch fixes it the same way how bits is computed earlier, by calling wide_int::from on the wi::to_wide (gimple_assign_rhs2 (stmt)), so we compare 64-bit 65535 with 64-bit 0xffffffff. 2024-02-02 Jakub Jelinek <ja...@redhat.com> PR middle-end/113705 * tree-ssa-math-opts.cc (is_widening_mult_rhs_p): Use wide_int_from around wi::to_wide in order to compare value in prec precision. * g++.dg/opt/pr113705.C: New test.
