re PR fortran/90577 (FAIL: gfortran.dg/lrshift_1.f90 with -O(2|3) and -flto)

2019-06-14  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/90577
	PR fortran/90578
	* trans-intrinsic.c (gfc_conv_intrinsic_shift): Properly
	distinguish logical/arithmetic shifts.
	* intrinsic.texi: Update documentation for SHIFTR/SHIFTL/SHIFTA
	(Fortran 2008) and LSHIFT/RSHIFT (GNU extensions).

	PR fortran/90577
	PR fortran/90578
	* gfortran.dg/lrshift_1.f90: Adjust testcase.
	* gfortran.dg/shiftalr_3.f90: New testcase.

From-SVN: r272309

3 files changed, 47 insertions, 23 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 9a82b9b..def1810 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,12 @@
+2019-06-14  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/90577
+	PR fortran/90578
+	* trans-intrinsic.c (gfc_conv_intrinsic_shift): Properly
+	distinguish logical/arithmetic shifts.
+	* intrinsic.texi: Update documentation for SHIFTR/SHIFTL/SHIFTA
+	(Fortran 2008) and LSHIFT/RSHIFT (GNU extensions).
+
 2019-06-14  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/89646
diff --git a/gcc/fortran/intrinsic.texi b/gcc/fortran/intrinsic.texi
index f3f4c00..f390761 100644
--- a/gcc/fortran/intrinsic.texi
+++ b/gcc/fortran/intrinsic.texi
@@ -9689,10 +9689,10 @@ The return value is a @code{INTEGER(4)} variable.
 @table @asis
 @item @emph{Description}:
 @code{LSHIFT} returns a value corresponding to @var{I} with all of the
-bits shifted left by @var{SHIFT} places.  If the absolute value of
-@var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined. 
-Bits shifted out from the left end are lost; zeros are shifted in from
-the opposite end.
+bits shifted left by @var{SHIFT} places.  @var{SHIFT} shall be
+nonnegative and less than or equal to @code{BIT_SIZE(I)}, otherwise
+the result value is undefined.  Bits shifted out from the left end are
+lost; zeros are shifted in from the opposite end.
 
 This function has been superseded by the @code{ISHFT} intrinsic, which
 is standard in Fortran 95 and later, and the @code{SHIFTL} intrinsic,
@@ -12244,11 +12244,12 @@ The value returned is equal to
 @table @asis
 @item @emph{Description}:
 @code{RSHIFT} returns a value corresponding to @var{I} with all of the
-bits shifted right by @var{SHIFT} places.  If the absolute value of
-@var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
-Bits shifted out from the right end are lost. The fill is arithmetic: the
-bits shifted in from the left end are equal to the leftmost bit, which in
-two's complement representation is the sign bit.
+bits shifted right by @var{SHIFT} places.  @var{SHIFT} shall be
+nonnegative and less than or equal to @code{BIT_SIZE(I)}, otherwise
+the result value is undefined.  Bits shifted out from the right end
+are lost. The fill is arithmetic: the bits shifted in from the left
+end are equal to the leftmost bit, which in two's complement
+representation is the sign bit.
 
 This function has been superseded by the @code{SHIFTA} intrinsic, which
 is standard in Fortran 2008 and later.
@@ -12783,11 +12784,12 @@ END PROGRAM
 @table @asis
 @item @emph{Description}:
 @code{SHIFTA} returns a value corresponding to @var{I} with all of the
-bits shifted right by @var{SHIFT} places.  If the absolute value of
-@var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
-Bits shifted out from the right end are lost. The fill is arithmetic: the
-bits shifted in from the left end are equal to the leftmost bit, which in
-two's complement representation is the sign bit.
+bits shifted right by @var{SHIFT} places.  @var{SHIFT} that be
+nonnegative and less than or equal to @code{BIT_SIZE(I)}, otherwise
+the result value is undefined.  Bits shifted out from the right end
+are lost. The fill is arithmetic: the bits shifted in from the left
+end are equal to the leftmost bit, which in two's complement
+representation is the sign bit.
 
 @item @emph{Standard}:
 Fortran 2008 and later
@@ -12823,10 +12825,10 @@ The return value is of type @code{INTEGER} and of the same kind as
 @table @asis
 @item @emph{Description}:
 @code{SHIFTL} returns a value corresponding to @var{I} with all of the
-bits shifted left by @var{SHIFT} places.  If the absolute value of
-@var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
-Bits shifted out from the left end are lost, and bits shifted in from
-the right end are set to 0.
+bits shifted left by @var{SHIFT} places.  @var{SHIFT} shall be
+nonnegative and less than or equal to @code{BIT_SIZE(I)}, otherwise
+the result value is undefined.  Bits shifted out from the left end are
+lost, and bits shifted in from the right end are set to 0.
 
 @item @emph{Standard}:
 Fortran 2008 and later
@@ -12862,10 +12864,10 @@ The return value is of type @code{INTEGER} and of the same kind as
 @table @asis
 @item @emph{Description}:
 @code{SHIFTR} returns a value corresponding to @var{I} with all of the
-bits shifted right by @var{SHIFT} places.  If the absolute value of
-@var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
-Bits shifted out from the right end are lost, and bits shifted in from
-the left end are set to 0.
+bits shifted right by @var{SHIFT} places.  @var{SHIFT} shall be
+nonnegative and less than or equal to @code{BIT_SIZE(I)}, otherwise
+the result value is undefined.  Bits shifted out from the right end
+are lost, and bits shifted in from the left end are set to 0.
 
 @item @emph{Standard}:
 Fortran 2008 and later
diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index f6edd68..cc041f9 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -6346,6 +6346,7 @@ gfc_conv_intrinsic_shift (gfc_se * se, gfc_expr * expr, bool right_shift,
 			  bool arithmetic)
 {
   tree args[2], type, num_bits, cond;
+  tree bigshift;
 
   gfc_conv_intrinsic_function_args (se, expr, args, 2);
 
@@ -6365,6 +6366,18 @@ gfc_conv_intrinsic_shift (gfc_se * se, gfc_expr * expr, bool right_shift,
   if (!arithmetic)
     se->expr = fold_convert (type, se->expr);
 
+  if (!arithmetic)
+    bigshift = build_int_cst (type, 0);
+  else
+    {
+      tree nonneg = fold_build2_loc (input_location, GE_EXPR,
+				     logical_type_node, args[0],
+				     build_int_cst (TREE_TYPE (args[0]), 0));
+      bigshift = fold_build3_loc (input_location, COND_EXPR, type, nonneg,
+				  build_int_cst (type, 0),
+				  build_int_cst (type, -1));
+    }
+
   /* The Fortran standard allows shift widths <= BIT_SIZE(I), whereas
      gcc requires a shift width < BIT_SIZE(I), so we have to catch this
      special case.  */
@@ -6373,7 +6386,7 @@ gfc_conv_intrinsic_shift (gfc_se * se, gfc_expr * expr, bool right_shift,
 			  args[1], num_bits);
 
   se->expr = fold_build3_loc (input_location, COND_EXPR, type, cond,
-			      build_int_cst (type, 0), se->expr);
+			      bigshift, se->expr);
 }
 
 /* ISHFT (I, SHIFT) = (abs (shift) >= BIT_SIZE (i))