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 <ja...@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
