[Bug target/53886] Seg fault in sh_insn_length_adjustment

[olegendo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53886

Oleg Endo <olegendo at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kkojima at gcc dot gnu.org

--- Comment #2 from Oleg Endo <olegendo at gcc dot gnu.org> 2012-07-08 11:40:56 UTC ---
I'm just guessing here, but this line

&& GET_CODE (PATTERN (NEXT_INSN (PREV_INSN (insn)))) != SEQUENCE

looks suspicious.  Most likely it's a nullptr access.
In sparc.c something similar is being done by the function
'int empty_delay_slot (rtx insn)'

Maybe the patch below could be a fix for the problem?
There are actually more places in sh.c where the usage of NEXT_INSN (PREV_INSN
(insn)) goes unchecked...

Kaz, what do you think?  Does this make any sense?


Index: gcc/config/sh/sh.c
===================================================================
--- gcc/config/sh/sh.c    (revision 189339)
+++ gcc/config/sh/sh.c    (working copy)
@@ -9652,6 +9652,15 @@
 #define IS_ASM_LOGICAL_LINE_SEPARATOR(C, STR) ((C) == ';')
 #endif

+static bool
+sequence_insn_p (rtx insn)
+{
+  if (PREV_INSN (insn) == NULL)
+    return false;
+
+  return GET_CODE (PATTERN (NEXT_INSN (PREV_INSN (insn)))) == SEQUENCE;
+}
+
 int
 sh_insn_length_adjustment (rtx insn)
 {
@@ -9662,7 +9671,7 @@
     && GET_CODE (PATTERN (insn)) != CLOBBER)
        || CALL_P (insn)
        || (JUMP_P (insn) && !JUMP_TABLE_DATA_P (insn)))
-      && GET_CODE (PATTERN (NEXT_INSN (PREV_INSN (insn)))) != SEQUENCE
+      && ! sequence_insn_p (insn)
       && get_attr_needs_delay_slot (insn) == NEEDS_DELAY_SLOT_YES)
     return 2;

@@ -9671,7 +9680,7 @@
   if (sh_cpu_attr == CPU_SH2E
       && JUMP_P (insn) && !JUMP_TABLE_DATA_P (insn)
       && get_attr_type (insn) == TYPE_CBRANCH
-      && GET_CODE (PATTERN (NEXT_INSN (PREV_INSN (insn)))) != SEQUENCE)
+      && ! sequence_insn_p (insn))
     return 2;

   /* sh-dsp parallel processing insn take four bytes instead of two.  */