Control: reassign -1 gcc-avr 1:14.2.0-1 thanks > /usr/lib/gcc/avr/14.2.0/../../../avr/bin/ld: snek-duemilanove-1.9.elf section > `.text' will not fit in region `text' > /usr/lib/gcc/avr/14.2.0/../../../avr/bin/ld: region `text' overflowed by 3436 > bytes
This huge increase in code size is caused by a change in that version of gcc which has been reverted upstream. That reversion patch (attached) can be applied to gcc version 14.2.0 to resolve the issue.
From adbdd39f1eb2864318609b9d397872abb36a67f3 Mon Sep 17 00:00:00 2001 From: Xianmiao Qu <cooper...@linux.alibaba.com> Date: Sun, 25 Aug 2024 11:22:21 -0600 Subject: [PATCH] [PATCH] Re-add calling emit_clobber in lower-subreg.cc's resolve_simple_move. The previous patch: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d8a6945c6ea22efa4d5e42fe1922d2b27953c8cd aimed to eliminate redundant MOV instructions by removing calling emit_clobber in lower-subreg.cc's resolve_simple_move. First, I found that another patch address this issue: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=bdf2737cda53a83332db1a1a021653447b05a7e7 and even without removing calling emit_clobber, the instruction generation is still as expected. Second, removing the CLOBBER expression will have side effects. When there is no CLOBBER expression and only SUBREG assignments exist, according to the logic of the 'df_lr_bb_local_compute' function, the register will be added to the basic block LR IN set. This will cause the register's lifetime to span the entire function, resulting in increased register pressure. Taking the newly added test case 'gcc/testsuite/gcc.target/riscv/pr43644.c' as an example, removing the CLOBBER expression will lead to spill in some registers. gcc/: * lower-subreg.cc (resolve_simple_move): Re-add calling emit_clobber immediately before moving a multi-word register by parts. gcc/testsuite/: * gcc.target/riscv/pr43644.c: New test case. --- gcc/lower-subreg.cc | 3 +++ gcc/testsuite/gcc.target/riscv/pr43644.c | 16 ++++++++++++++++ 2 files changed, 19 insertions(+) create mode 100644 gcc/testsuite/gcc.target/riscv/pr43644.c diff --git a/gcc/lower-subreg.cc b/gcc/lower-subreg.cc index d1da94336e7..89608934c99 100644 --- a/gcc/lower-subreg.cc +++ b/gcc/lower-subreg.cc @@ -1101,6 +1101,9 @@ resolve_simple_move (rtx set, rtx_insn *insn) { unsigned int i; + if (REG_P (dest) && !HARD_REGISTER_NUM_P (REGNO (dest))) + emit_clobber (dest); + for (i = 0; i < words; ++i) { rtx t = simplify_gen_subreg_concatn (word_mode, dest, diff --git a/gcc/testsuite/gcc.target/riscv/pr43644.c b/gcc/testsuite/gcc.target/riscv/pr43644.c new file mode 100644 index 00000000000..3b7ddb9e0ad --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/pr43644.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-options "-march=rv32imac -mabi=ilp32 -O2 -fdump-rtl-ira" } */ + +double foo (double a) +{ + if (a < 0.0) + return a + 1.0; + else if (a > 16.0) + return a - 3.0; + else if (a < 300.0) + return a - 30.0; + else + return a; +} + +/* { dg-final { scan-rtl-dump-not "memory is more profitable" "ira" } } */ -- 2.45.2
-- -keith
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