[PATCH] Handle epilogues that contain jumps

[PATCH] Handle epilogues that contain jumps

[Richard Sandiford]

The prologue/epilogue pass allows the prologue sequence
to contain jumps.  The sequence is then partitioned into
basic blocks using find_many_sub_basic_blocks.

This patch treats epilogues in the same way.  It's needed for
a follow-on aarch64 patch that adds conditional code to both
the prologue and the epilogue.

Tested on aarch64-linux-gnu (including with a follow-on patch)
and x86_64-linux-gnu.  OK to install?

Richard


gcc/
	* function.cc (thread_prologue_and_epilogue_insns): Handle
	epilogues that contain jumps.
---
 gcc/function.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/function.cc b/gcc/function.cc
index d3da20ede7f..b54a1d81a3b 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -6136,6 +6136,11 @@ thread_prologue_and_epilogue_insns (void)
 		  && returnjump_p (BB_END (e->src)))
 		e->flags &= ~EDGE_FALLTHRU;
 	    }
+
+	  auto_sbitmap blocks (last_basic_block_for_fn (cfun));
+	  bitmap_clear (blocks);
+	    bitmap_set_bit (blocks, BLOCK_FOR_INSN (epilogue_seq)->index);
+	  find_many_sub_basic_blocks (blocks);
 	}
       else if (next_active_insn (BB_END (exit_fallthru_edge->src)))
 	{
@@ -6234,6 +6239,11 @@ thread_prologue_and_epilogue_insns (void)
 	  set_insn_locations (seq, epilogue_location);
 
 	  emit_insn_before (seq, insn);
+
+	  auto_sbitmap blocks (last_basic_block_for_fn (cfun));
+	  bitmap_clear (blocks);
+	  bitmap_set_bit (blocks, BLOCK_FOR_INSN (insn)->index);
+	  find_many_sub_basic_blocks (blocks);
 	}
     }
 
-- 
2.25.1

Re: [PATCH] Handle epilogues that contain jumps

[Jeff Law]

On 11/11/22 09:19, Richard Sandiford via Gcc-patches wrote:
> The prologue/epilogue pass allows the prologue sequence
> to contain jumps.  The sequence is then partitioned into
> basic blocks using find_many_sub_basic_blocks.
>
> This patch treats epilogues in the same way.  It's needed for
> a follow-on aarch64 patch that adds conditional code to both
> the prologue and the epilogue.
>
> Tested on aarch64-linux-gnu (including with a follow-on patch)
> and x86_64-linux-gnu.  OK to install?
>
> Richard
>
>
> gcc/
> 	* function.cc (thread_prologue_and_epilogue_insns): Handle
> 	epilogues that contain jumps.

OK

jeff