re PR fortran/57160 (short-circuit IF only with -ffrontend-optimize)

2018-08-10  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/57160
	* invoke.texi (frontend-optimize): Mention short-circuiting.
	* options.c (gfc_post_options): Disable -ffrontend-optimize with -Og.
	* resolve.c (resolve_operator): Warn about short-circuiting only with
	-ffrontend-optimize.
	* trans-expr.c (gfc_conv_expr_op): Use short-circuiting operators only
	with -ffrontend-optimize. Without that flag, make sure that both
	operands are evaluated.

2018-08-10  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/57160
	* gfortran.dg/actual_pointer_function_1.f90: Fix invalid test case.
	* gfortran.dg/inline_matmul_23.f90: Add option "-ffrontend-optimize".
	* gfortran.dg/short_circuiting_2.f90: New test case.
	* gfortran.dg/short_circuiting_3.f90: New test case.

From-SVN: r263471

5 files changed, 27 insertions, 11 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 7051509..26ff784 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,14 @@
+2018-08-10  Janus Weil  <janus@gcc.gnu.org>
+
+	PR fortran/57160
+	* invoke.texi (frontend-optimize): Mention short-circuiting.
+	* options.c (gfc_post_options): Disable -ffrontend-optimize with -Og.
+	* resolve.c (resolve_operator): Warn about short-circuiting only with
+	-ffrontend-optimize.
+	* trans-expr.c (gfc_conv_expr_op): Use short-circuiting operators only
+	with -ffrontend-optimize. Without that flag, make sure that both
+	operands are evaluated.
+
 2018-08-08  Nathan Sidwell  <nathan@acm.org>
 
 	* cpp.c (cb_file_change): Use linemap_included_from.
diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index 093864b..ee84a0b 100644
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -1793,13 +1793,17 @@ if @option{-ffrontend-optimize} is in effect.
 @opindex @code{frontend-optimize}
 @cindex Front-end optimization
 This option performs front-end optimization, based on manipulating
-parts the Fortran parse tree.  Enabled by default by any @option{-O}
-option.  Optimizations enabled by this option include inlining calls
-to @code{MATMUL}, elimination of identical function calls within
-expressions, removing unnecessary calls to @code{TRIM} in comparisons
-and assignments and replacing @code{TRIM(a)} with
-@code{a(1:LEN_TRIM(a))}.  It can be deselected by specifying
-@option{-fno-frontend-optimize}.
+parts the Fortran parse tree.  Enabled by default by any @option{-O} option
+except @option{-O0} and @option{-Og}.  Optimizations enabled by this option
+include:
+@itemize @bullet
+@item inlining calls to @code{MATMUL},
+@item elimination of identical function calls within expressions,
+@item removing unnecessary calls to @code{TRIM} in comparisons and assignments,
+@item replacing @code{TRIM(a)} with @code{a(1:LEN_TRIM(a))} and
+@item short-circuiting of logical operators (@code{.AND.} and @code{.OR.}).
+@end itemize
+It can be deselected by specifying @option{-fno-frontend-optimize}.
 
 @item -ffrontend-loop-interchange
 @opindex @code{frontend-loop-interchange}
diff --git a/gcc/fortran/options.c b/gcc/fortran/options.c
index af93751..e8db54d4 100644
--- a/gcc/fortran/options.c
+++ b/gcc/fortran/options.c
@@ -417,7 +417,7 @@ gfc_post_options (const char **pfilename)
      specified it directly.  */
 
   if (flag_frontend_optimize == -1)
-    flag_frontend_optimize = optimize;
+    flag_frontend_optimize = optimize && !optimize_debug;
 
   /* Same for front end loop interchange.  */
 
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 3035e02..16146e6 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -3982,7 +3982,8 @@ resolve_operator (gfc_expr *e)
 	  else if (op2->ts.kind < e->ts.kind)
 	    gfc_convert_type (op2, &e->ts, 2);
 
-	  if (e->value.op.op == INTRINSIC_AND || e->value.op.op == INTRINSIC_OR)
+	  if (flag_frontend_optimize &&
+	    (e->value.op.op == INTRINSIC_AND || e->value.op.op == INTRINSIC_OR))
 	    {
 	      /* Warn about short-circuiting
 	         with impure function as second operand.  */
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index dfc44f7..54e318e 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -3348,12 +3348,12 @@ gfc_conv_expr_op (gfc_se * se, gfc_expr * expr)
       return;
 
     case INTRINSIC_AND:
-      code = TRUTH_ANDIF_EXPR;
+      code = flag_frontend_optimize ? TRUTH_ANDIF_EXPR : TRUTH_AND_EXPR;
       lop = 1;
       break;
 
     case INTRINSIC_OR:
-      code = TRUTH_ORIF_EXPR;
+      code = flag_frontend_optimize ? TRUTH_ORIF_EXPR : TRUTH_OR_EXPR;
       lop = 1;
       break;