[gcc r12-7764] tree-optimization/105012 - fix ICE from local DSE of if-conversion

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:08f263e703c4100fa7b9f08cb26cee6c0bd75e4a

commit r12-7764-g08f263e703c4100fa7b9f08cb26cee6c0bd75e4a
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Mar 22 12:28:30 2022 +0100

    tree-optimization/105012 - fix ICE from local DSE of if-conversion
    
    The following guards dse_classify_store with the same condition as
    the DSE pass does - availability of a virtual definition.  For
    the PR we run into the fortran frontend generating a clobber for
    a FUNCTION_DECL lhs which is ignored by the operand scanner and has
    no virtual operands assigned.  Apart from fixing the frontend the
    following fixes the ICE by adjusting if-conversion.
    
    2022-03-22  Richard Biener  <rguenther@suse.de>
    
            PR tree-optimization/105012
            * tree-if-conv.cc (ifcvt_local_dce): Only call
            dse_classify_store when we have a VDEF.

Diff:
---
 gcc/tree-if-conv.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 375628e6e9e..7495ed653c0 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -3145,7 +3145,7 @@ ifcvt_local_dce (class loop *loop)
       gimple_stmt_iterator gsiprev = gsi;
       gsi_prev (&gsiprev);
       stmt = gsi_stmt (gsi);
-      if (gimple_store_p (stmt))
+      if (gimple_store_p (stmt) && gimple_vdef (stmt))
 	{
 	  tree lhs = gimple_get_lhs (stmt);
 	  ao_ref write;