* tree-ssa-dom.c (propagate_rhs_into_lhs): Temporarily work

	around bug in immediate-use iterator.

	* gcc.c-torture/compile/pr26833.c: New test.
	* gfortran.fortran-torture/compile/pr26806.f90: New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@112348 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 0 deletions

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index daa2f0ea81d..9df59e9dc52 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -2134,6 +2134,7 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
       /* Walk over every use of LHS and try to replace the use with RHS. 
 	 At this point the only reason why such a propagation would not
 	 be successful would be if the use occurs in an ASM_EXPR.  */
+    repeat:
       FOR_EACH_IMM_USE_SAFE (use_p, iter, lhs)
 	{
 	  tree use_stmt = USE_STMT (use_p);
@@ -2264,6 +2265,24 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
 	    }
 	}
 
+      /* Due to a bug in the immediate use iterator code, we can
+	 miss visiting uses in some cases when there is more than
+	 one use in a statement.  Missing a use can cause a multitude
+         of problems if we expected to eliminate all uses and remove
+         the defining statement.
+
+	 Until Andrew can fix the iterator, this hack will detect
+	 the cases which cause us problems.  Namely if ALL is set
+	 and we still have some immediate uses, then we must have
+	 skipped one or more in the loop above.  So just re-execute
+	 the loop.
+
+	 The maximum number of times we can re-execute the loop is
+	 bounded by the maximum number of times a given SSA_NAME
+	 appears in a single statement.  */
+      if (all && num_imm_uses (lhs) != 0)
+	goto repeat;
+
       /* If we were able to propagate away all uses of LHS, then
 	 we can remove STMT.  */
       if (all)