From 9850348784435131aa3d78feab4c93dd34481dde Mon Sep 17 00:00:00 2001 From: Ramana Radhakrishnan Date: Wed, 28 Jun 2017 22:09:50 +0000 Subject: [PATCH] [AArch64] Do not increase data alignment at -Os and with -fconserve-stack. We unnecessarily align data to 8 byte alignments even when -Os is specified. This brings the logic in the AArch64 backend more in line with the ARM backend and helps gain some image size in a few places. Caught by an internal report on the size of rodata sections being high with aarch64 gcc. * config/aarch64/aarch64.h (AARCH64_EXPAND_ALIGNMENT): New. (DATA_ALIGNMENT): Update to use AARCH64_EXPAND_ALIGNMENT. (LOCAL_ALIGNMENT): Update to use AARCH64_EXPAND_ALIGNMENT. Bootstrapped and regression tested on aarch64-none-linux-gnu with no regressions. From-SVN: r249764 --- gcc/ChangeLog | 6 ++++++ gcc/config/aarch64/aarch64.h | 26 ++++++++++++++++++-------- 2 files changed, 24 insertions(+), 8 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c7523753620..5211806db14 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-06-28 Ramana Radhakrishnan + + * config/aarch64/aarch64.h (AARCH64_EXPAND_ALIGNMENT): New. + (DATA_ALIGNMENT): Update to use AARCH64_EXPAND_ALIGNMENT. + (LOCAL_ALIGNMENT): Update to use AARCH64_EXPAND_ALIGNMENT. + 2017-06-28 Sebastian Peryt * config/i386/avx512vlintrin.h (_mm256_permutexvar_epi64) diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index 3b3f27e2f95..106cf3a5666 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -98,14 +98,24 @@ && (ALIGN) < BITS_PER_WORD) \ ? BITS_PER_WORD : ALIGN) -#define DATA_ALIGNMENT(EXP, ALIGN) \ - ((((ALIGN) < BITS_PER_WORD) \ - && (TREE_CODE (EXP) == ARRAY_TYPE \ - || TREE_CODE (EXP) == UNION_TYPE \ - || TREE_CODE (EXP) == RECORD_TYPE)) \ - ? BITS_PER_WORD : (ALIGN)) - -#define LOCAL_ALIGNMENT(EXP, ALIGN) DATA_ALIGNMENT(EXP, ALIGN) +/* Align definitions of arrays, unions and structures so that + initializations and copies can be made more efficient. This is not + ABI-changing, so it only affects places where we can see the + definition. Increasing the alignment tends to introduce padding, + so don't do this when optimizing for size/conserving stack space. */ +#define AARCH64_EXPAND_ALIGNMENT(COND, EXP, ALIGN) \ + (((COND) && ((ALIGN) < BITS_PER_WORD) \ + && (TREE_CODE (EXP) == ARRAY_TYPE \ + || TREE_CODE (EXP) == UNION_TYPE \ + || TREE_CODE (EXP) == RECORD_TYPE)) ? BITS_PER_WORD : (ALIGN)) + +/* Align global data. */ +#define DATA_ALIGNMENT(EXP, ALIGN) \ + AARCH64_EXPAND_ALIGNMENT (!optimize_size, EXP, ALIGN) + +/* Similarly, make sure that objects on the stack are sensibly aligned. */ +#define LOCAL_ALIGNMENT(EXP, ALIGN) \ + AARCH64_EXPAND_ALIGNMENT (!flag_conserve_stack, EXP, ALIGN) #define STRUCTURE_SIZE_BOUNDARY 8 -- 2.30.2