[PATCH] Fix ICE due to copy_reg_eh_region_note_forward (PR rtl-optimization/89234)

[Jakub Jelinek]

Hi!

The following testcase ICEs on ppc64le.  The problem is that
copy_reg_eh_region_note_* functions accept either some instruction, or
REG_EH_REGION note directly.  To differentiate between those it uses INSN_P
test (and returns early if the insn doesn't contain any REG_EH_REGION
notes).  If the function is called on a rtx_insn * that isn't INSN_P, like
on the testcase on a NOTE, it assumes it must be REG_EH_REGION note, uses
XEXP (note, 0) on it, which is actually PREV_INSN in this case and stores
an instruction (JUMP_INSN in this case) into REG_EH_REGION notes it creates.

I believe we should treat rtx_insn * that aren't INSN_P like instructions
that don't have any REG_EH_REGION notes.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2019-02-07  Jakub Jelinek  <ja...@redhat.com>

        PR rtl-optimization/89234
        * except.c (copy_reg_eh_region_note_forward): Return if note_or_insn
        is a NOTE, CODE_LABEL etc. - rtx_insn * other than INSN_P.
        (copy_reg_eh_region_note_backward): Likewise.

        * g++.dg/ubsan/pr89234.C: New test.

--- gcc/except.c.jj     2019-01-10 11:43:14.387377695 +0100
+++ gcc/except.c        2019-02-07 15:11:27.756869475 +0100
@@ -1756,6 +1756,8 @@ copy_reg_eh_region_note_forward (rtx not
       if (note == NULL)
        return;
     }
+  else if (is_a <rtx_insn *> (note_or_insn))
+    return;
   note = XEXP (note, 0);
 
   for (insn = first; insn != last ; insn = NEXT_INSN (insn))
@@ -1778,6 +1780,8 @@ copy_reg_eh_region_note_backward (rtx no
       if (note == NULL)
        return;
     }
+  else if (is_a <rtx_insn *> (note_or_insn))
+    return;
   note = XEXP (note, 0);
 
   for (insn = last; insn != first; insn = PREV_INSN (insn))
--- gcc/testsuite/g++.dg/ubsan/pr89234.C.jj     2019-02-07 17:12:02.081024666 
+0100
+++ gcc/testsuite/g++.dg/ubsan/pr89234.C        2019-02-07 17:08:55.026097949 
+0100
@@ -0,0 +1,11 @@
+// PR rtl-optimization/89234
+// { dg-do compile { target dfp } }
+// { dg-options "-O2 -fnon-call-exceptions -fsanitize=null" }
+
+typedef float __attribute__((mode (SD))) _Decimal32;
+
+void
+foo (_Decimal32 *b, _Decimal32 c)
+{
+  *b = c + 1.5;
+}

        Jakub