Re: Fix ICE on loop over constant vector at -O

[Eric Botcazou]

> ... so if would really be a pessimization doing that.  Of course handling
> CONST_DECL in for_each_index is indeed obvious - I just was curios if
> it was a missed-optimization opportunity as well.

It turns out that, for the same testcase, &CONST_DECL is generated on the MIPS 
and prepare_decl_rtl is trying to put an RTX on the CONST_DECL, hence ICE.

Tested on x86_64-suse-linux, applied on the mainline as obvious.  I agree that 
this is on the fringes of what we have to support, but we won't revisit it 
until the 4.9 development cycle.


2012-12-11  Eric Botcazou  <ebotca...@adacore.com>

        * tree-ssa-loop-ivopts.c (prepare_decl_rtl) <ADDR_EXPR>: Generate RTL
        only for a DECL which HAS_RTL_P.


-- 
Eric Botcazou
Index: tree-ssa-loop-ivopts.c
===================================================================
--- tree-ssa-loop-ivopts.c	(revision 194382)
+++ tree-ssa-loop-ivopts.c	(working copy)
@@ -2806,7 +2806,7 @@ prepare_decl_rtl (tree *expr_p, int *ws,
 	   expr_p = &TREE_OPERAND (*expr_p, 0))
 	continue;
       obj = *expr_p;
-      if (DECL_P (obj) && !DECL_RTL_SET_P (obj))
+      if (DECL_P (obj) && HAS_RTL_P (obj) && !DECL_RTL_SET_P (obj))
         x = produce_memory_decl_rtl (obj, regno);
       break;