[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 Martin Liška changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|--- |FIXED --- Comment #10 from Martin Liška --- Implemented in trunk now.
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 --- Comment #9 from Martin Liška --- Author: marxin Date: Wed Jul 4 07:51:08 2018 New Revision: 262375 URL: https://gcc.gnu.org/viewcvs?rev=262375=gcc=rev Log: 2018-07-04 Denys Vlasenko Martin Liska PR middle-end/66240 PR target/45996 PR c/84100 * common.opt: Rename align options with 'str_' prefix. * common/config/i386/i386-common.c (set_malign_value): New function. (ix86_handle_option): Use it to set -falign-* options/ * config/aarch64/aarch64-protos.h (struct tune_params): Change type from int to string. * config/aarch64/aarch64.c: Update default values from int to string. * config/alpha/alpha.c (alpha_override_options_after_change): Likewise. * config/arm/arm.c (arm_override_options_after_change_1): Likewise. * config/i386/dragonfly.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. * config/i386/freebsd.h (SUBALIGN_LOG): New. (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. * config/i386/gas.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. * config/i386/gnu-user.h (SUBALIGN_LOG): New. (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. * config/i386/i386.c (struct ptt): Change type from int to string. (ix86_default_align): Set default values. * config/i386/i386.h (ASM_OUTPUT_MAX_SKIP_PAD): Print max skip conditionally. * config/i386/iamcu.h (SUBALIGN_LOG): New. (ASM_OUTPUT_MAX_SKIP_ALIGN): * config/i386/lynx.h (ASM_OUTPUT_MAX_SKIP_ALIGN): * config/i386/netbsd-elf.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. * config/i386/openbsdelf.h (SUBALIGN_LOG): New. (ASM_OUTPUT_MAX_SKIP_ALIGN) Print max skip conditionally.: * config/i386/x86-64.h (SUBALIGN_LOG): New. (ASM_OUTPUT_MAX_SKIP_ALIGN): Print max skip conditionally. (ASM_OUTPUT_MAX_SKIP_PAD): Likewise. * config/ia64/ia64.c (ia64_option_override): Set default values for alignment options. * config/m68k/m68k.c: Handle new str_align_* options. * config/mips/mips.c (mips_set_compression_mode): Change type of constants. (mips_option_override): Set default values for options. * config/powerpcspe/powerpcspe.c (rs6000_option_override_internal): Likewise. * config/rs6000/rs6000.c (rs6000_option_override_internal): Likewise. * config/rx/rx.c (rx_option_override): Likewise. * config/rx/rx.h (JUMP_ALIGN): Use align_jumps_log. (LABEL_ALIGN): Use align_labels_log. (LOOP_ALIGN): Use align_loops_align. * config/s390/s390.c (s390_asm_output_function_label): Use new macros. * config/sh/sh.c (sh_override_options_after_change): Change type of constants. * config/spu/spu.c (spu_sched_init): Likewise. * config/sparc/sparc.c (sparc_option_override): Set default values for options. * config/visium/visium.c (visium_option_override): Likewise. * config/visium/visium.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Do not emit p2align format with last argument if it's not needed. * doc/invoke.texi: Document extended format of -falign-*. * final.c: Use align_labels alignment. * flags.h (struct target_flag_state): Change type to use align_flags. (struct align_flags_tuple): New. (struct align_flags): Likewise. (align_loops_log): Redefine macro to use new types. (align_loops_max_skip): Redefine macro to use new types. (align_jumps_log): Redefine macro to use new types. (align_jumps_max_skip): Redefine macro to use new types. (align_labels_log): Redefine macro to use new types. (align_labels_max_skip): Redefine macro to use new types. (align_functions_log): Redefine macro to use new types. (align_loops): Redefine macro to use new types. (align_jumps): Redefine macro to use new types. (align_labels): Redefine macro to use new types. (align_functions): Redefine macro to use new types. (align_functions_max_skip): Redefine macro to use new types. (align_loops_value): New macro. (align_jumps_value): New macro. (align_labels_value): New macro. (align_functions_value): New macro. * function.c (invoke_set_current_function_hook): Propagate alignment values from flags to global variables default in topleev.h. * ipa-icf.c (sem_function::equals_wpa): Use cl_optimization_option_eq instead of memcmp. * lto-streamer.h (cl_optimization_stream_out): Support streaming of string types. (cl_optimization_stream_in): Likewise. * optc-save-gen.awk:
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 Jeffrey A. Law changed: What|Removed |Added CC||law at redhat dot com --- Comment #8 from Jeffrey A. Law --- In response to c#2 and c#3, you're more likely to get that kind of "ideal" solution by hacking the linker rather than the compiler or assembler. The linker is in an ideal position to make these kinds of decisions. You can even use the linker to fill in padding at the end of a function with a nearby teeny-tiny function. You don't want to do that too aggressively though because often functions in the same CU often call each other and you can easily muck up locality if you move a teeny-tiny function too far from its parents or children in the call graph/chain. If you want to get really smart, you start collecting data about the call graph, chains and frequencies, icache and itlb behavior and use that to drive general code layout to improve icache/itlb behavior as well as smart alignments of functions. Been there, done that :-)
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 --- Comment #7 from Denis Vlasenko --- Patch v8 https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00792.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00793.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00794.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00795.html
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 --- Comment #6 from Denis Vlasenko --- Patches v7 are posted: https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00720.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00721.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00722.html https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00723.html
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 --- Comment #5 from Denis Vlasenko --- Patches v3 posted to the mailing list: https://gcc.gnu.org/ml/gcc-patches/2016-08/msg02073.html https://gcc.gnu.org/ml/gcc-patches/2016-08/msg02074.html
[Bug middle-end/66240] RFE: extend -falign-xyz syntax
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240 --- Comment #4 from Denis Vlasenko --- Created attachment 38293 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38293=edit Proposed patch This patch implements -falign-functions=N[,M] for now, with the eye for easy extension to other -falign options. I tested that with -falign-functions=N (tried 8, 15, 16, 17...) the alignment directives are the same before and after the patch: -falign-functions=8 generates ".p2align 3,,7" before and after. -falign-functions=17 generates ".p2align 5,,16" before and after. I tested that -falign-functions=N,N (two equal paramenters) works exactly like -falign-functions=N. Patch drops currently performed forced alignment to 8 if requested alignment is higher than 8: before the patch, -falign-functions=9 was generating .p2align 4,,8 .p2align 3 which means "Align to 16 if the skip is 8 bytes or less; else align to 8". After the patch, "p2align 3" is not emitted. I drop that because I ultimately want to do something like -falign-functions=64,8 - IOW, I want to align functions by 64 bytes, but only if that entails a skip of less than 8 bytes - otherwise I want **no alignment at all**. The forced ".p2align 3" interferes with that intention. This is an RFC-patch, IOW: I don't insist on removal of ".p2align 3" generation. I imagine that it should be retained for compat, and yet another option should be added to suppress it if desired (how about "-mno-8byte-code-subalign"? Argh...)
