On 29/09/2021 12:20, Kyrylo Tkachov via Gcc-patches wrote:
Hi all, Similar to my previous patch for setmem this one does the same for the cpymem expansion. We count the number of ops emitted and compare it against the alternative of just calling the library function when optimising for size. For the code: void cpy_127 (char *out, char *in) { __builtin_memcpy (out, in, 127); } void cpy_128 (char *out, char *in) { __builtin_memcpy (out, in, 128); } we now emit a call to memcpy (with an extra MOV-immediate instruction for the size) instead of: cpy_127(char*, char*): ldp q0, q1, [x1] stp q0, q1, [x0] ldp q0, q1, [x1, 32] stp q0, q1, [x0, 32] ldp q0, q1, [x1, 64] stp q0, q1, [x0, 64] ldr q0, [x1, 96] str q0, [x0, 96] ldr q0, [x1, 111] str q0, [x0, 111] ret cpy_128(char*, char*): ldp q0, q1, [x1] stp q0, q1, [x0] ldp q0, q1, [x1, 32] stp q0, q1, [x0, 32] ldp q0, q1, [x1, 64] stp q0, q1, [x0, 64] ldp q0, q1, [x1, 96] stp q0, q1, [x0, 96] ret which is a clear code size win. Speed optimisation heuristics remain unchanged. Bootstrapped and tested on aarch64-none-linux-gnu. Pushing to trunk. Thanks, Kyrill 2021-09-29 Kyrylo Tkachov <kyrylo.tkac...@arm.com> * config/aarch64/aarch64.c (aarch64_expand_cpymem): Count number of emitted operations and adjust heuristic for code size.2021-09-29 Kyrylo Tkachov <kyrylo.tkac...@arm.com>* gcc.target/aarch64/cpymem-size.c: New test.
Hi Kyrill, Just to mention that the new test fails with -mabi=ilp32... Thanks, Christophe
