From 7b30a12edf7a3a461bbfc9cbb29b3050c7164032 Mon Sep 17 00:00:00 2001 From: Daniel Cederman Date: Mon, 12 Oct 2020 08:50:35 +0200 Subject: [PATCH] sparc: Prevent atomic instructions in beginning of functions for UT700 A call to the function might have a load instruction in the delay slot and a load followed by an atomic function could cause a deadlock. gcc/ChangeLog: * config/sparc/sparc.c (sparc_do_work_around_errata): Do not begin functions with atomic instruction in the UT700 errata workaround. --- gcc/config/sparc/sparc.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c index 2487caf72dad..6f419f6fd586 100644 --- a/gcc/config/sparc/sparc.c +++ b/gcc/config/sparc/sparc.c @@ -1124,6 +1124,7 @@ static unsigned int sparc_do_work_around_errata (void) { rtx_insn *insn, *next; + bool find_first_useful = true; /* Force all instructions to be split into their final form. */ split_all_insns_noflow (); @@ -1148,6 +1149,16 @@ sparc_do_work_around_errata (void) else jump = NULL; + /* Do not begin function with atomic instruction. */ + if (sparc_fix_ut700 + && find_first_useful + && USEFUL_INSN_P (insn)) + { + find_first_useful = false; + if (atomic_insn_for_leon3_p (insn)) + emit_insn_before (gen_nop (), insn); + } + /* Place a NOP at the branch target of an integer branch if it is a floating-point operation or a floating-point branch. */ if (sparc_fix_gr712rc -- 2.47.2