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[committed,rtl-optimization/93996] Avoid adding REG_NOTEs to anything other than INSNs

Message ID ea96872a55ddd182646877f55998b68302dd6bab.camel@redhat.com
State New
Headers show
Series [committed,rtl-optimization/93996] Avoid adding REG_NOTEs to anything other than INSNs | expand

Commit Message

Jeff Law March 6, 2020, 3:39 p.m. UTC 
As noted in PR93996, haifa-sched can try to add REG_NOTEs to a NOTE_INSN.  This
causes memory corruption which typically shows up as a fault in the GC system.

What happens is we have an insn before the EPILOGUE_BEG note.  That insn needs to
be split and the split form creates new basic blocks.

As a result we have a NOTE_INSN_BASIC_BLOCK right after the NOTE_EPILOGUE_BEG
while the code in haifa-sched.c assume the next insn after the NOTE_EPILOGUE_BEG
would be a real insn.

The primary patch is Andrews.  All I did was bullet proof it a bit by ensuring
that we don't go past next_tail and asserting that after skippiong the
NOTE_INSN_BASIC_BLOCK that we've got an INSN.

Bootstrapped and regression tested on x86 and a variety of other platforms
overnight in the tester.

Committing to the trunk.

Jeff
commit e6ce69cae5059dfd715edd4e26653c23baf4cb0f
Author: Andrew Pinski <apinski@marvell.com>
Date:   Fri Mar 6 08:34:01 2020 -0700

    Avoid putting a REG_NOTE on anything other than an INSN in haifa-sched.c
    
            PR rtl-optimization/93996
            * haifa-sched.c (remove_notes): Be more careful when adding
            REG_SAVE_NOTE.
diff mbox series

Patch

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 843648314ae..e38af8ed620 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@ 
+2020-03-06  Andrew Pinski  <apinski@marvell.com>
+	    Jeff Law  <law@redhat.com>
+
+	PR rtl-optimization/93996
+	* haifa-sched.c (remove_notes): Be more careful when adding
+	REG_SAVE_NOTE.
+
 2020-03-06  Delia Burduv  <delia.burduv@arm.com>
 
 	* config/arm/arm_neon.h (vld2_bf16): New.
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 1d3de7b6a76..80687fb5359 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -4239,6 +4239,15 @@  remove_notes (rtx_insn *head, rtx_insn *tail)
 	  if (insn != tail)
 	    {
 	      remove_insn (insn);
+	      /* If an insn was split just before the EPILOGUE_BEG note and
+		 that split created new basic blocks, we could have a
+		 BASIC_BLOCK note here.  Safely advance over it in that case
+		 and assert that we land on a real insn.  */
+	      if (NOTE_P (next)
+		  && NOTE_KIND (next) == NOTE_INSN_BASIC_BLOCK
+		  && next != next_tail)
+		next = NEXT_INSN (next);
+	      gcc_assert (INSN_P (next));
 	      add_reg_note (next, REG_SAVE_NOTE,
 			    GEN_INT (NOTE_INSN_EPILOGUE_BEG));
 	      break;