Re: [Patch, IRA] Fix a function accessing beyond end-of-array

[Vladimir Makarov]

On 05/11/2011 10:07 AM, Hari Sandanagobalane wrote:

Hello,

I discussed this problem with Vlad in http://gcc.gnu.org/ml/gcc/2011-05/msg00131.html. I propose the following patch to fix it. Okay to commit?

Revised the ChangeLog.

Thanks
Hari

ChangeLog:

* ira.c (clarify_prohibited_class_mode_regs): Prevent the function from accessing beyond the end of REGNO_REG_CLASS array by stopping the loop early.

Patch:
Index: gcc/ira.c
===================================================================
--- gcc/ira.c   (revision 173654)
+++ gcc/ira.c   (working copy)
@@ -1422,6 +1422,12 @@

if (TEST_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j], hard_regno))

             continue;
           nregs = hard_regno_nregs[hard_regno][j];
+          if (hard_regno + nregs >= FIRST_PSEUDO_REGISTER)

I think it should be '>' not '>='

With this change, the patch is ok.  Thanks for the patch.

+            {
+              SET_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j],
+                                hard_regno);
+               continue;
+            }

pclass = ira_pressure_class_translate[REGNO_REG_CLASS (hard_regno)];

           for (nregs-- ;nregs >= 0; nregs--)
             if (((enum reg_class) pclass