diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/function.c | 25 |
2 files changed, 32 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6cde480..15e1b86 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,6 +1,13 @@ 2011-04-05 Tom de Vries <tom@codesourcery.com> PR target/43920 + * function.c (emit_use_return_register_into_block): New function. + (thread_prologue_and_epilogue_insns): Use + emit_use_return_register_into_block. + +2011-04-05 Tom de Vries <tom@codesourcery.com> + + PR target/43920 * cfgcleanup.c (flow_find_cross_jump): Don't count USE or CLOBBER as insn. diff --git a/gcc/function.c b/gcc/function.c index a1ea482..7c500a6 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -5262,6 +5262,19 @@ prologue_epilogue_contains (const_rtx insn) return 0; } +/* Insert use of return register before the end of BB. */ + +static void +emit_use_return_register_into_block (basic_block bb) +{ + rtx seq; + start_sequence (); + use_return_register (); + seq = get_insns (); + end_sequence (); + emit_insn_before (seq, BB_END (bb)); +} + #ifdef HAVE_return /* Insert gen_return at the end of block BB. This also means updating block_for_insn appropriately. */ @@ -5416,6 +5429,15 @@ thread_prologue_and_epilogue_insns (void) with a simple return instruction. */ if (simplejump_p (jump)) { + /* The use of the return register might be present in the exit + fallthru block. Either: + - removing the use is safe, and we should remove the use in + the exit fallthru block, or + - removing the use is not safe, and we should add it here. + For now, we conservatively choose the latter. Either of the + 2 helps in crossjumping. */ + emit_use_return_register_into_block (bb); + emit_return_into_block (bb); delete_insn (jump); } @@ -5430,6 +5452,9 @@ thread_prologue_and_epilogue_insns (void) continue; } + /* See comment in simple_jump_p case above. */ + emit_use_return_register_into_block (bb); + /* If this block has only one successor, it both jumps and falls through to the fallthru block, so we can't delete the edge. */ |