https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123523
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <[email protected]>: https://gcc.gnu.org/g:dd8df074c9ceaa723e82f06bef8714f46ecccb18 commit r16-6706-gdd8df074c9ceaa723e82f06bef8714f46ecccb18 Author: Jakub Jelinek <[email protected]> Date: Mon Jan 12 10:06:47 2026 +0100 simplify-rtx: Fix up shift/rotate VOIDmode count handling [PR123523] The following testcase ICEs on i686-linux, because the HW in that case implements the shift as shifting by 64-bit count (anything larger or equal to number of bits in the first operand's element results in 0 or sign copies), so the machine description implements it as such as well. Now, because shifts/rotates can have different modes on the first and second operand, when the second one has VOIDmode (i.e. CONST_INT, I think CONST_WIDE_INT has non-VOIDmode and CONST_DOUBLE with VOIDmode is hopefully very rarely used), we need to choose some mode for the wide_int conversion. And so far we've been choosing BITS_PER_WORD/word_mode or the mode of the first operand's element, whichever is wider. That works fine on 64-bit targets, CONST_INT has always at most 64 bits, but for 32-bit targets uses SImode. Because HOST_BITS_PER_WIDE_INT is always 64, the following patch just uses that plus DImode instead of BITS_PER_WORD and word_mode. 2026-01-12 Jakub Jelinek <[email protected]> PR rtl-optimization/123523 * simplify-rtx.cc (simplify_const_binary_operation): Use DImode for VOIDmode shift and truncation counts if int_mode is narrower than HOST_BITS_PER_WIDE_INT rather than word_mode if int_mode it is narrower than BITS_PER_WORD. * gcc.target/i386/pr123523.c: New test.
