fortran: Fix o'...' boz to integer/real conversions [PR96859]

The standard says that excess digits from boz are truncated.
For hexadecimal or binary, the routines copy just the number of digits
that will be needed, but for octal we copy number of digits that
contain one extra bit (for 8-bit, 32-bit or 128-bit, i.e. kind 1, 4 and 16)
or two extra bits (for 16-bit or 64-bit, i.e. kind 2 and 8).
The clearing of the first bit is done correctly by changing the first digit
if it is 4-7 to one smaller by 4 (i.e. modulo 4).
The clearing of the first two bits is done by changing 4 or 6 to 0
and 5 or 7 to 1, which is incorrect, because we really want to change the
first digit to 0 if it was even, or to 1 if it was odd, so digits
2 and 3 are mishandled by keeping them as is, rather than changing 2 to 0
and 3 to 1.

2020-09-02  Jakub Jelinek  <jakub@redhat.com>

	PR fortran/96859
	* check.c (gfc_boz2real, gfc_boz2int): When clearing first two bits,
	change also '2' to '0' and '3' to '1' rather than just handling '4'
	through '7'.

	* gfortran.dg/pr96859.f90: New test.

(cherry picked from commit b567d3bd302933adb253aba9069fd8120c485441)

diff --git a/gcc/fortran/check.c b/gcc/fortran/check.c
index 4d50906a3f372482d4921a8776ca9cab21078fac..ca6f582625d30642463fd269eea974b4b8b6e2e9 100644 (file)
--- a/gcc/fortran/check.c
+++ b/gcc/fortran/check.c
@@ -340,9 +340,9 @@ gfc_boz2real (gfc_expr *x, int kind)
       /* Clear first two bits.  */
       else
        {
-         if (buf[0] == '4' || buf[0] == '6')
+         if (buf[0] == '2' || buf[0] == '4' || buf[0] == '6')
            buf[0] = '0';
-         else if (buf[0] == '5' || buf[0] == '7')
+         else if (buf[0] == '3' || buf[0] == '5' || buf[0] == '7')
            buf[0] = '1';
        }
     }
@@ -429,9 +429,9 @@ gfc_boz2int (gfc_expr *x, int kind)
       /* Clear first two bits.  */
       else
        {
-         if (buf[0] == '4' || buf[0] == '6')
+         if (buf[0] == '2' || buf[0] == '4' || buf[0] == '6')
            buf[0] = '0';
-         else if (buf[0] == '5' || buf[0] == '7')
+         else if (buf[0] == '3' || buf[0] == '5' || buf[0] == '7')
            buf[0] = '1';
        }
     }

diff --git a/gcc/testsuite/gfortran.dg/pr96859.f90 b/gcc/testsuite/gfortran.dg/pr96859.f90
new file mode 100644 (file)
index 0000000..ca41cef
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr96859.f90
@@ -0,0 +1,25 @@
+! PR fortran/96859
+! { dg-do run }
+
+program pr96859
+  if (merge_bits(32767_2, o'1234567', 32767_2).ne.32767_2) stop 1
+  if (merge_bits(o'1234567', 32767_2, o'1234567').ne.32767_2) stop 2
+  if (merge_bits(32767_2, o'1234567', b'010101').ne.14711_2) stop 3
+  if (merge_bits(32767_2, o'1234567', z'12345678').ne.32639_2) stop 4
+  if (int (o'1034567', 2).ne.14711_2) stop 5
+  if (int (o'1234567', 2).ne.14711_2) stop 6
+  if (int (o'1434567', 2).ne.14711_2) stop 7
+  if (int (o'1634567', 2).ne.14711_2) stop 8
+  if (int (o'1134567', 2).ne.-18057_2) stop 9
+  if (int (o'1334567', 2).ne.-18057_2) stop 10
+  if (int (o'1534567', 2).ne.-18057_2) stop 11
+  if (int (o'1734567', 2).ne.-18057_2) stop 12
+  if (int (o'70123456776543211234567', 8).ne.1505855851274254711_8) stop 13
+  if (int (o'72123456776543211234567', 8).ne.1505855851274254711_8) stop 14
+  if (int (o'74123456776543211234567', 8).ne.1505855851274254711_8) stop 15
+  if (int (o'76123456776543211234567', 8).ne.1505855851274254711_8) stop 16
+  if (int (o'71123456776543211234567', 8).ne.-7717516185580521097_8) stop 17
+  if (int (o'73123456776543211234567', 8).ne.-7717516185580521097_8) stop 18
+  if (int (o'75123456776543211234567', 8).ne.-7717516185580521097_8) stop 19
+  if (int (o'77123456776543211234567', 8).ne.-7717516185580521097_8) stop 20
+end