https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113690
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Roger Sayle <sa...@gcc.gnu.org>: https://gcc.gnu.org/g:99200573096c03120c8d4514383951acecdd5ab1 commit r14-8868-g99200573096c03120c8d4514383951acecdd5ab1 Author: Roger Sayle <ro...@nextmovesoftware.com> Date: Wed Feb 7 14:21:34 2024 +0000 PR target/113690: Remove TImode REG_EQUAL notes in STV. This patch fixes PR target/113690, an ICE-on-valid regression on x86_64 that exhibits with a specific combination of command line options. The cause is that x86's scalar-to-vector pass converts a chain of instructions from TImode to V1TImode, but fails to appropriately update or delete the attached REG_EQUAL note. This implements Uros' recommendation of removing these notes. For convenience, this code (re)factors the logic to convert a TImode constant into a V1TImode constant vector into a subroutine and reuses it. For the record, STV is actually doing something useful in this strange testcase, GCC with -O2 -fno-dce -fno-forward-propagate -fno-split-wide-types -funroll-loops generates: foo: movl $v, %eax pxor %xmm0, %xmm0 movaps %xmm0, 48(%rax) movaps %xmm0, (%rax) movaps %xmm0, 16(%rax) movaps %xmm0, 32(%rax) ret With the addition of -mno-stv (to disable the patched code) it gives: foo: movl $v, %eax movq $0, 48(%rax) movq $0, 56(%rax) movq $0, (%rax) movq $0, 8(%rax) movq $0, 16(%rax) movq $0, 24(%rax) movq $0, 32(%rax) movq $0, 40(%rax) ret 2024-02-07 Roger Sayle <ro...@nextmovesoftware.com> Uros Bizjak <ubiz...@gmail.com> gcc/ChangeLog PR target/113690 * config/i386/i386-features.cc (timode_convert_cst): New helper function to convert a TImode CONST_SCALAR_INT_P to a V1TImode CONST_VECTOR. (timode_scalar_chain::convert_op): Use timode_convert_cst. (timode_scalar_chain::convert_insn): Delete REG_EQUAL notes. Use timode_convert_cst. gcc/testsuite/ChangeLog PR target/113690 * gcc.target/i386/pr113690.c: New test case.
