On Sat, 2023-11-18 at 14:59 +0800, Guo Jie wrote: > For the following immediate load operation in > gcc/testsuite/gcc.target/loongarch/imm-load1.c: > > long long r = 0x0101010101010101; > > Before this patch: > > lu12i.w $r15,16842752>>12 > ori $r15,$r15,257 > lu32i.d $r15,0x1010100000000>>32 > lu52i.d $r15,$r15,0x100000000000000>>52 > > After this patch: > > lu12i.w $r15,16842752>>12 > ori $r15,$r15,257 > bstrins.d $r15,$r15,63,32 > > gcc/ChangeLog: > > * config/loongarch/loongarch.cc (enum loongarch_load_imm_method): Add > new method. > (loongarch_build_integer): Add relevant implementations for new method. > (loongarch_move_integer): Ditto.
IIRC the ChangeLog line should be wrapped at 72 characters. /* snip */ > struct loongarch_integer_op > @@ -1556,11 +1560,23 @@ loongarch_build_integer (struct loongarch_integer_op > *codes, > > int sign31 = (value & (HOST_WIDE_INT_1U << 31)) >> 31; > int sign51 = (value & (HOST_WIDE_INT_1U << 51)) >> 51; > + > + unsigned HOST_WIDE_INT hival = value >> 32; > + unsigned HOST_WIDE_INT loval = value << 32 >> 32; Use uint32_t hival = (uint32_t) (value >> 32); uint32_t loval = (uint32_t) value; instead, because "value << 32" may trigger a left-shift of negative value. C++11 doesn't allow shifting left any negative value. Yes it's allowed as a GCC extension and it's also allowed by C++23, but GCC codebase is still C++11. So it may break GCC if bootstrapping from a different compiler, and --with-build-config=bootstrap-ubsan will complain. Otherwise LGTM. -- Xi Ruoyao <xry...@xry111.site> School of Aerospace Science and Technology, Xidian University
