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From: Jakub Jelinek <jakub@redhat.com>
To: Jeff Law <law@redhat.com>, Richard Biener <rguenther@suse.de>,
	       Eric Botcazou <ebotcazou@libertysurf.fr>
Cc: gcc-patches@gcc.gnu.org
Subject: [PATCH] Perform cfg cleanup in cse if needed (PR rtl-optimization/92610)
Date: Sat, 23 Nov 2019 02:11:00 -0000	[thread overview]
Message-ID: <20191123011536.GI2466@tucnak> (raw)

Hi!

cse_main which sets tem has:
  if (cse_jumps_altered || recorded_label_ref)
    return 2;
  else if (cse_cfg_altered)
    return 1;
  else
    return 0;
at the end, but after these two functions call it, they call also
delete_trivially_dead_insns.  Even when cse_main didn't need cfg changes,
delete_trivially_dead_insns could remove a trivially dead insn that had
EH edges and so we might still need to remove unreachable blocks.

The following patch implements it.  Bootstrapped/regtested on x86_64-linux
and i686-linux, ok for trunk?

2019-11-23  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/92610
	* cse.c (rest_of_handle_cse2): Call cleanup_cfg (0) also if
	cse_cfg_altered is set, even when tem is 0.
	(rest_of_handle_cse_after_global_opts): Likewise.

	* g++.dg/opt/pr92610.C: New test.

--- gcc/cse.c.jj	2019-11-19 22:27:01.960059340 +0100
+++ gcc/cse.c	2019-11-22 15:51:34.639806155 +0100
@@ -7701,7 +7701,7 @@ rest_of_handle_cse2 (void)
       cse_cfg_altered |= cleanup_cfg (CLEANUP_CFG_CHANGED);
       timevar_pop (TV_JUMP);
     }
-  else if (tem == 1)
+  else if (tem == 1 || cse_cfg_altered)
     cse_cfg_altered |= cleanup_cfg (0);
 
   cse_not_expected = 1;
@@ -7775,7 +7775,7 @@ rest_of_handle_cse_after_global_opts (vo
       cse_cfg_altered |= cleanup_cfg (CLEANUP_CFG_CHANGED);
       timevar_pop (TV_JUMP);
     }
-  else if (tem == 1)
+  else if (tem == 1 || cse_cfg_altered)
     cse_cfg_altered |= cleanup_cfg (0);
 
   flag_cse_follow_jumps = save_cfj;
--- gcc/testsuite/g++.dg/opt/pr92610.C.jj	2019-11-22 15:52:46.254734331 +0100
+++ gcc/testsuite/g++.dg/opt/pr92610.C	2019-11-22 15:53:14.991303498 +0100
@@ -0,0 +1,13 @@
+// PR rtl-optimization/92610
+// { dg-do compile }
+// { dg-options "-w -fdelete-dead-exceptions --param=sccvn-max-alias-queries-per-access=0 -fno-dse -fnon-call-exceptions -Os -funroll-loops -ftrapv" }
+
+struct C { int x; ~C () {} };
+
+int
+main ()
+{
+  C *buffer = new C[42];
+  buffer[-3].x = 42;
+  delete [] buffer;
+}

	Jakub

             reply	other threads:[~2019-11-23  1:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-23  2:11 Jakub Jelinek [this message]
2019-11-23  6:56 ` Richard Biener

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