frontend-passes.c (optimize_assignment): Follow chains of concatenation…

frontend-passes.c (optimize_assignment): Follow chains of concatenation operators to the end for removing trailing TRIMS...

2011-05-11  Thomas Koenig  <tkoenig@gcc.gnu.org>

	* frontend-passes.c (optimize_assignment): Follow chains
	of concatenation operators to the end for removing trailing
	TRIMS for assignments.

2011-05-11  Thomas Koenig  <tkoenig@gcc.gnu.org>

	* gfortran.dg/trim_optimize_7.f90:  New test.

From-SVN: r174944

gcc/fortran/ChangeLog

+2011-05-11  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	* frontend-passes.c (optimize_assignment): Follow chains
+	of concatenation operators to the end for removing trailing
+	TRIMS for assignments.
+
 2011-06-10  Daniel Carrera  <dcarrera@gmail.com>
 
 	* trans-decl.c (gfc_build_builtin_function_decls):

gcc/fortran/frontend-passes.c

@@ -500,6 +500,14 @@ optimize_assignment (gfc_code * c)
 
   if (lhs->ts.type == BT_CHARACTER)
     {
+      /* Check for a // b // trim(c).  Looping is probably not
+	 necessary because the parser usually generates
+	 (// (// a b ) trim(c) ) , but better safe than sorry.  */
+
+      while (rhs->expr_type == EXPR_OP
+	     && rhs->value.op.op == INTRINSIC_CONCAT)
+	rhs = rhs->value.op.op2;
+
       if (rhs->expr_type == EXPR_FUNCTION &&
 	  rhs->value.function.isym &&
 	  rhs->value.function.isym->id == GFC_ISYM_TRIM)

gcc/testsuite/ChangeLog

+2011-05-11  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	* gfortran.dg/trim_optimize_7.f90:  New test.
+
 2011-06-10  Wei Guozhi  <carrot@google.com>
 
 	PR target/45335

gcc/testsuite/gfortran.dg/trim_optimize_7.f90

+! { dg-do run }
+! { dg-options "-O -fdump-tree-original" }
+! Check that trailing trims are also removed from assignment of
+! expressions involving concatenations of strings .
+program main
+  character(2) :: a,b,c
+  character(8) :: d
+  a = 'a '
+  b = 'b '
+  c = 'c '
+  d = a // b // a // trim(c)   ! This should be optimized away.
+  if (d /= 'a b a c ') call abort
+  d = a // trim(b) // c // a   ! This shouldn't.
+  if (d /= 'a bc a  ') call abort
+  d = a // b // a // trim(trim(c)) ! This should also be optimized away.
+  if (d /= 'a b a c ') call abort
+end
+! { dg-final { scan-tree-dump-times "string_len_trim" 1 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }