https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116043
--- Comment #19 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by hongtao Liu <liuho...@gcc.gnu.org>: https://gcc.gnu.org/g:c94738e2462ff46f3013f6270f6a955b749d82b2 commit r12-10668-gc94738e2462ff46f3013f6270f6a955b749d82b2 Author: liuhongt <hongtao....@intel.com> Date: Wed Jul 24 11:29:23 2024 +0800 Refine constraint "Bk" to define_special_memory_constraint. For below pattern, RA may still allocate r162 as v/k register, try to reload for address with leaq __libc_tsd_CTYPE_B@gottpoff(%rip), %rsi which result a linker error. (set (reg:DI 162) (mem/u/c:DI (const:DI (unspec:DI [(symbol_ref:DI ("a") [flags 0x60] <var_decl 0x7f621f6e1c60 a>)] UNSPEC_GOTNTPOFF)) Quote from H.J for why linker issue an error. >What do these do: > > leaq __libc_tsd_CTYPE_B@gottpoff(%rip), %rax > vmovq (%rax), %xmm0 > >From x86-64 TLS psABI: > >The assembler generates for the x@gottpoff(%rip) expressions a R X86 >64 GOTTPOFF relocation for the symbol x which requests the linker to >generate a GOT entry with a R X86 64 TPOFF64 relocation. The offset of >the GOT entry relative to the end of the instruction is then used in >the instruction. The R X86 64 TPOFF64 relocation is pro- cessed at >program startup time by the dynamic linker by looking up the symbol x >in the modules loaded at that point. The offset is written in the GOT >entry and later loaded by the addq instruction. > >The above code sequence looks wrong to me. gcc/ChangeLog: PR target/116043 * config/i386/constraints.md (Bk): Refine to define_special_memory_constraint. gcc/testsuite/ChangeLog: * gcc.target/i386/pr116043.c: New test. (cherry picked from commit bc1fda00d5f20e2f3e77a50b2822562b6e0040b2)
