[patch] combine ICE fix

[Cesar Philippidis]

On 10/10/13 9:25 AM, Jakub Jelinek wrote:

> That looks broken.  You leave everything from the last size till the current
> one uninitialized, so it would only work if combine_split_insns
> always increments max_reg_num () by at most one.

Good catch.

> Furthermore, there are macros which should be used to access
> the fields, and, if the vector is ever going to be resized, supposedly
> it should be vec.h vector rather than just array.
> Or perhaps take into account:
> /* If a pass need to change these values in some magical way or the
>    pass needs to have accurate values for these and is not using
>    incremental df scanning, then it should use REG_N_SETS and
>    REG_N_USES.  If the pass is doing incremental scanning then it
>    should be getting the info from DF_REG_DEF_COUNT and
>    DF_REG_USE_COUNT.  */
> and not use REG_N_SETS etc. but instead the df stuff.

I was thinking about converting that array to a vec. But I don't want to
touch more code than I have to right now. Is this OK as a stopgap?

Thanks for the review!

Cesar
-------------- next part --------------
2013-10-11  Cesar Philippidis  <cesar@codesourcery.com>

	gcc/
	* regs.h (REG_N_GROW): New function. 
	* combine.c (combine_split_insns): Call REG_N_GROW when
	new registers are created.

Index: gcc/regs.h
===================================================================
--- gcc/regs.h	(revision 203289)
+++ gcc/regs.h	(working copy)
@@ -89,6 +89,20 @@ REG_N_SETS (int regno)
 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
 
+/* Indexed by n, inserts new registers (old_regno+1)..new_regno.  */
+static inline void
+REG_N_GROW (int new_regno, int old_regno)
+{
+  regstat_n_sets_and_refs = XRESIZEVEC (struct regstat_n_sets_and_refs_t, 
+					regstat_n_sets_and_refs, new_regno+1);
+
+  for (int i = old_regno + 1; i <= new_regno; ++i)
+    {
+      SET_REG_N_SETS (i, 1);
+      SET_REG_N_REFS (i, 1);
+    }
+}
+
 /* Given a REG, return TRUE if the reg is a PARM_DECL, FALSE otherwise.  */
 extern bool reg_is_parm_p (rtx);
 
Index: gcc/combine.c
===================================================================
--- gcc/combine.c	(revision 203289)
+++ gcc/combine.c	(working copy)
@@ -518,7 +518,10 @@ combine_split_insns (rtx pattern, rtx insn)
   ret = split_insns (pattern, insn);
   nregs = max_reg_num ();
   if (nregs > reg_stat.length ())
-    reg_stat.safe_grow_cleared (nregs);
+    {
+      REG_N_GROW (nregs, reg_stat.length ());
+      reg_stat.safe_grow_cleared (nregs);
+    }
   return ret;
 }