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V3 [PATCH] i386: Handle REG_EH_REGION note


On 3/14/19, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Mar 14, 2019 at 4:34 PM Jakub Jelinek <jakub@redhat.com> wrote:
>>
>> On Thu, Mar 14, 2019 at 11:30:21AM +0800, H.J. Lu wrote:
>> > We need to split the basic block if we create new insns, which may
>> > throw exceptions, in the middle of the basic blocks.
>> >
>> > Tested on AVX2 and AVX512 machines with and without
>> >
>> > --with-arch=native
>> >
>> > OK for trunk?
>>
>> That looks much better, I see you chose to follow what lower-subreg.c
>> does
>> here.  I just wonder if instead of the sbitmap of blocks to check for
>> splitting it
>> wouldn't be more efficient to have an auto_vec<rtx_insn *> holding the
>> exact
>> set_insns that need splitting after them and just grab the bb using
>> BLOCK_FOR_INSN.
>>
>
> Good idea.  I will work on it.
>

Here it is.  OK for trunk?

Thanks.

-- 
H.J.
From 64ac61ce7095c49406ea34b05f1c22fbb98ca3f7 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 12 Mar 2019 08:55:24 +0800
Subject: [PATCH] i386: Handle REG_EH_REGION note

When we split:

(insn 18 17 76 2 (set (reg:SF 88 [ _19 ])
        (float:SF (mem/c:SI (symbol_ref:DI ("d") [flags 0x2]  <var_decl 0x7fd6d8290c60 d>) [1 d+0 S4 A32]))) "x.ii":4:20 170 {*floatsisf2}
     (expr_list:REG_EH_REGION (const_int 2 [0x2])
        (nil)))

to

(insn 94 17 18 2 (set (reg:V4SF 115)
        (vec_merge:V4SF (vec_duplicate:V4SF (float:SF (mem/c:SI (symbol_ref:DI ("d") [flags 0x2]  <var_decl 0x7f346837ac60 d>) [1 d+0 S4 A32])))
            (reg:V4SF 114)
            (const_int 1 [0x1]))) "x.ii":4:20 -1
     (nil))
(insn 18 94 76 2 (set (reg:SF 88 [ _19 ])
        (subreg:SF (reg:V4SF 115) 0)) "x.ii":4:20 112 {*movsf_internal}
     (expr_list:REG_EH_REGION (const_int 2 [0x2])
        (nil)))

we must copy the REG_EH_REGION note to the first insn and split the block
after the newly added insn.  The REG_EH_REGION on the second insn will be
removed later since it no longer traps.

gcc/

	PR target/89650
	* config/i386/i386.c (remove_partial_avx_dependency): Handle
	REG_EH_REGION note.

gcc/testsuite/

	PR target/89650
	* g++.target/i386/pr89650.C: New test.
---
 gcc/config/i386/i386.c                  | 42 +++++++++++++++++++++++++
 gcc/testsuite/g++.target/i386/pr89650.C | 19 +++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 gcc/testsuite/g++.target/i386/pr89650.C

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 1f94a45909d..93ff46f329a 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -2819,6 +2819,8 @@ remove_partial_avx_dependency (void)
   rtx set;
   rtx v4sf_const0 = NULL_RTX;
 
+  auto_vec<rtx_insn *> splitted_insn;
+
   FOR_EACH_BB_FN (bb, cfun)
     {
       FOR_BB_INSNS (bb, insn)
@@ -2875,6 +2877,17 @@ remove_partial_avx_dependency (void)
 	  set_insn = emit_insn_before (set, insn);
 	  df_insn_rescan (set_insn);
 
+	  if (cfun->can_throw_non_call_exceptions)
+	    {
+	      /* Handle REG_EH_REGION note.  */
+	      rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
+	      if (note)
+		{
+		  splitted_insn.safe_push (set_insn);
+		  add_reg_note (set_insn, REG_EH_REGION, XEXP (note, 0));
+		}
+	    }
+
 	  src = gen_rtx_SUBREG (dest_mode, vec, 0);
 	  set = gen_rtx_SET (dest, src);
 
@@ -2925,6 +2938,35 @@ remove_partial_avx_dependency (void)
       df_insn_rescan (set_insn);
       df_process_deferred_rescans ();
       loop_optimizer_finalize ();
+
+      if (!splitted_insn.is_empty ())
+	{
+	  free_dominance_info (CDI_DOMINATORS);
+
+	  unsigned int i;
+	  FOR_EACH_VEC_ELT (splitted_insn, i, insn)
+	    {
+	      rtx_insn *end;
+	      edge fallthru;
+
+	      bb = BLOCK_FOR_INSN (insn);
+	      end = BB_END (bb);
+
+	      while (insn != end)
+		if (control_flow_insn_p (insn))
+		  {
+		    /* Split the block after insn.  There will be a
+		       fallthru edge, which is OK so we keep it.  We
+		       have to create the exception edges ourselves.  */
+		    fallthru = split_block (bb, insn);
+		    rtl_make_eh_edge (NULL, bb, BB_END (bb));
+		    bb = fallthru->dest;
+		    insn = BB_HEAD (bb);
+		  }
+		else
+		  insn = NEXT_INSN (insn);
+	    }
+	}
     }
 
   bitmap_obstack_release (NULL);
diff --git a/gcc/testsuite/g++.target/i386/pr89650.C b/gcc/testsuite/g++.target/i386/pr89650.C
new file mode 100644
index 00000000000..4b253cbf467
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr89650.C
@@ -0,0 +1,19 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -flive-range-shrinkage -fno-tree-dce -fno-dce -fnon-call-exceptions -mavx" }
+
+int d, e;
+struct g {
+  float f;
+  g(float h) : f(h + d) {}
+  ~g() {}
+};
+struct i {
+  int a;
+  int b : 4;
+  int &c;
+  i(int h) : a(), b(), c(h) {}
+};
+int main() {
+  i j(e);
+  g k[]{1, 2};
+}
-- 
2.20.1


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