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[PATCH][5/4] Fix PR87117


Another one.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2018-08-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87117
	* tree-ssa-sccvn.c (eliminate_dom_walker::eliminate_stmt): Only
	re-value-number released SSA VDEFs.

	* gfortran.dg/pr87117.f90: New testcase.

Index: gcc/tree-ssa-sccvn.c
===================================================================
--- gcc/tree-ssa-sccvn.c	(revision 263917)
+++ gcc/tree-ssa-sccvn.c	(working copy)
@@ -4979,8 +4979,14 @@ eliminate_dom_walker::eliminate_stmt (ba
 	  propagate_tree_value_into_stmt (gsi, sprime);
 	  stmt = gsi_stmt (*gsi);
 	  update_stmt (stmt);
+	  /* In case the VDEF on the original stmt was released, value-number
+	     it to the VUSE.  This is to make vuse_ssa_val able to skip
+	     released virtual operands.  */
 	  if (vdef != gimple_vdef (stmt))
-	    VN_INFO (vdef)->valnum = vuse;
+	    {
+	      gcc_assert (SSA_NAME_IN_FREE_LIST (vdef));
+	      VN_INFO (vdef)->valnum = vuse;
+	    }
 
 	  /* If we removed EH side-effects from the statement, clean
 	     its EH information.  */
@@ -5258,7 +5264,10 @@ eliminate_dom_walker::eliminate_stmt (ba
 	    fprintf (dump_file, "  Removed AB side-effects.\n");
 	}
       update_stmt (stmt);
-      if (vdef != gimple_vdef (stmt))
+      /* In case the VDEF on the original stmt was released, value-number
+         it to the VUSE.  This is to make vuse_ssa_val able to skip
+	 released virtual operands.  */
+      if (vdef && SSA_NAME_IN_FREE_LIST (vdef))
 	VN_INFO (vdef)->valnum = vuse;
     }
 
Index: gcc/testsuite/gfortran.dg/pr87117.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr87117.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/pr87117.f90	(working copy)
@@ -0,0 +1,14 @@
+! { dg-do compile }
+! { dg-options "-O" }
+program p
+   real(4) :: a, b
+   integer(4) :: n, m
+   equivalence (a, n)
+   a = 1024.0
+   m = 8
+   a = 1024.0
+   b = set_exponent(a, m)
+   n = 8
+   a = f(a, n)
+   b = set_exponent(a, m)
+end


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