https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98694
--- 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:e711b67a9081ae84c66174a50705dc98ba993a43 commit r11-6828-ge711b67a9081ae84c66174a50705dc98ba993a43 Author: liuhongt <hongtao....@intel.com> Date: Mon Jan 18 16:55:32 2021 +0800 Fix incorrect optimization by cprop_hardreg. If SRC had been assigned a mode narrower than the copy, we can't always link DEST into the chain even they have same hard_regno_nregs(i.e. HImode/SImode in i386 backend). i.e kmovw %k0, %edi vmovd %edi, %xmm2 vpshuflw $0, %xmm2, %xmm0 kmovw %k0, %r8d kmovd %k0, %r9d ... - movl %r9d, %r11d + vmovd %xmm2, %r11d gcc/ChangeLog: PR rtl-optimization/98694 * regcprop.c (copy_value): If SRC had been assigned a mode narrower than the copy, we can't link DEST into the chain even they have same hard_regno_nregs(i.e. HImode/SImode in i386 backend). gcc/testsuite/ChangeLog: PR rtl-optimization/98694 * gcc.target/i386/pr98694.c: New test.
