Patchwork Fix ICE during out-of-SSA

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Submitter Eric Botcazou
Date July 18, 2012, 2:54 p.m.
Message ID <201207181654.16090.ebotcazou@adacore.com>
Download mbox | patch
Permalink /patch/171703/
State New
Headers show

Comments

Eric Botcazou - July 18, 2012, 2:54 p.m.
This is a regression present on mainline and 4.7 branch for targets using SJLJ 
exceptions by default in Ada (e.g. ARM).  The error message is:

Unable to coalesce ssa_names 2 and 20 which are marked as MUST COALESCE.
b1_2(ab) and  b1_20(ab)
+===========================GNAT BUG DETECTED==============================+
| 4.8.0 20120716 (experimental) [trunk revision 189525] (x86_64-suse-linux) GCC 
error:|
| SSA corruption                                                           |
| Error detected around p.adb:4:1     

It's the usual case of overlapping live ranges for (ab) SSA names.

Tested on x86_64-suse-linux, OK for the mainline and 4.7 branch?


2012-07-18  Eric Botcazou  <ebotcazou@adacore.com>

	* tree-ssa-forwprop.c (combine_conversions): Punt if the RHS of the
	defining statement is a SSA name that occurs in abnormal PHIs.


2012-07-18  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/aggr20.ad[sb]: New test.
	* gnat.dg/aggr20_pkg.ads: New helper.
Richard Guenther - July 18, 2012, 3:01 p.m.
On Wed, Jul 18, 2012 at 4:54 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> This is a regression present on mainline and 4.7 branch for targets using SJLJ
> exceptions by default in Ada (e.g. ARM).  The error message is:
>
> Unable to coalesce ssa_names 2 and 20 which are marked as MUST COALESCE.
> b1_2(ab) and  b1_20(ab)
> +===========================GNAT BUG DETECTED==============================+
> | 4.8.0 20120716 (experimental) [trunk revision 189525] (x86_64-suse-linux) GCC
> error:|
> | SSA corruption                                                           |
> | Error detected around p.adb:4:1
>
> It's the usual case of overlapping live ranges for (ab) SSA names.
>
> Tested on x86_64-suse-linux, OK for the mainline and 4.7 branch?

Ok.

Thanks,
Richard.

>
> 2012-07-18  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * tree-ssa-forwprop.c (combine_conversions): Punt if the RHS of the
>         defining statement is a SSA name that occurs in abnormal PHIs.
>
>
> 2012-07-18  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * gnat.dg/aggr20.ad[sb]: New test.
>         * gnat.dg/aggr20_pkg.ads: New helper.
>
>
> --
> Eric Botcazou

Patch

Index: tree-ssa-forwprop.c
===================================================================
--- tree-ssa-forwprop.c	(revision 189525)
+++ tree-ssa-forwprop.c	(working copy)
@@ -2584,6 +2584,11 @@  combine_conversions (gimple_stmt_iterato
       unsigned int final_prec = TYPE_PRECISION (type);
       int final_unsignedp = TYPE_UNSIGNED (type);
 
+      /* Don't propagate ssa names that occur in abnormal phis.  */
+      if (TREE_CODE (defop0) == SSA_NAME
+	  && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (defop0))
+	return 0;
+
       /* In addition to the cases of two conversions in a row
 	 handled below, if we are converting something to its own
 	 type via an object of identical or wider precision, neither