re PR tree-optimization/32220 (internal compiler error: in…

re PR tree-optimization/32220 (internal compiler error: in eliminate_temp_copies, at tree-predcom.c:1937)

	PR tree-optimization/32220
	* tree-predcom.c (eliminate_temp_copies): Handle the case that loop
	phi node is reached before defining statement.

	* gfortran.dg/predcom-2.f: New testcase.

From-SVN: r125531

gcc/ChangeLog

+2007-06-07  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR tree-optimization/32220
+	* tree-predcom.c (eliminate_temp_copies): Handle the case that loop
+	phi node is reached before defining statement.
+
 2007-06-06  Andrew Pinski  <andrew_pinski@playstation.sony.com>
 
 	PR tree-opt/32231

gcc/testsuite/ChangeLog

+2007-06-07  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR tree-optimization/32220
+	* gfortran.dg/predcom-2.f: New testcase.
+
 2007-06-06  Andrew Pinski  <andrew_pinski@playstation.sony.com>
 
 	PR tree-opt/32231

gcc/testsuite/gfortran.dg/predcom-2.f

+! PR 32220, ICE when the loop is not unrolled enough to eliminate all 
+!   register copies
+! { dg-do compile }
+! { dg-options "-O3" }
+
+      subroutine derv (b,cosxy,thick)
+c
+      common /shell4/xji(3,3)
+c
+      dimension cosxy(6,*),
+     1          thick(*),b(*)
+c
+
+      do 125 i=1,3
+      b(k2+i)=xji(i,1) + xji(i,2) + xji(i,3)
+  125 b(k3+i)=cosxy(i+3,kk) + cosxy(i,kk)
+c
+c
+      return
+      end

gcc/tree-predcom.c

@@ -1932,7 +1932,13 @@ eliminate_temp_copies (struct loop *loop, bitmap tmp_vars)
 
       /* Base all the ssa names in the ud and du chain of NAME on VAR.  */
       stmt = SSA_NAME_DEF_STMT (use);
-      while (TREE_CODE (stmt) == PHI_NODE)
+      while (TREE_CODE (stmt) == PHI_NODE
+	     /* In case we could not unroll the loop enough to eliminate
+		all copies, we may reach the loop header before the defining
+		statement (in that case, some register copies will be present
+		in loop latch in the final code, corresponding to the newly
+		created looparound phi nodes).  */
+	     && bb_for_stmt (stmt) != loop->header)
 	{
 	  gcc_assert (single_pred_p (bb_for_stmt (stmt)));
 	  use = PHI_ARG_DEF (stmt, 0);