From: Thomas Koenig <tkoenig@gcc.gnu.org>
Date: Tue, 2 Jan 2018 23:03:11 +0000 (+0000)
Subject: backport: re PR fortran/83650 (Wrong simplification in cshift with negative shifts)
X-Git-Tag: releases/gcc-6.5.0~613
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d72b97244038dffad86df70281bd4e23c2b21d0c;p=thirdparty%2Fgcc.git

backport: re PR fortran/83650 (Wrong simplification in cshift with negative shifts)

2018-01-02  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from 7-branch
	PR fortran/83650
	* simplify.c (gfc_simplify_cshift): Correct contition for
	negative shifts.

2018-01-02  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from 7-branch
	PR fortran/83650
	* gfortran.dg/simplify_cshift_1.f90: Correct condition.

From-SVN: r256113
---

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index f278002b90a2..18d014e02937 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,10 @@
+2018-01-02  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	Backport from 7-branch
+	PR fortran/83650
+	* simplify.c (gfc_simplify_cshift): Correct contition for
+	negative shifts.
+
 2017-11-13  Paul Thomas  <pault@gcc.gnu.org>
 
 	Backport from trunk
diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
index 37c04e9bf27d..ea7a74644213 100644
--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -1839,7 +1839,9 @@ gfc_simplify_cshift (gfc_expr *array, gfc_expr *shift, gfc_expr *dim)
       mpz_clear (size);
 
       /* Adjust shft to deal with right or left shifts. */
-      shft = shft < 0 ? 1 - shft : shft;
+      shft = shft % sz;
+      if (shft < 0)
+       shft += sz;
 
       /* Special case: Shift to the original order!  */
       if (sz == 0 || shft % sz == 0)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9cd07f37dd9e..89d3c776dff4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-02  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	Backport from 7-branch
+	PR fortran/83650
+	* gfortran.dg/simplify_cshift_1.f90: Correct condition.
+
 2017-12-14  Peter Bergner  <bergner@vnet.ibm.com>
 
 	Backport from mainline
diff --git a/gcc/testsuite/gfortran.dg/simplify_cshift_1.f90 b/gcc/testsuite/gfortran.dg/simplify_cshift_1.f90
index dbe67f4c8e9a..3eb5adb49c81 100644
--- a/gcc/testsuite/gfortran.dg/simplify_cshift_1.f90
+++ b/gcc/testsuite/gfortran.dg/simplify_cshift_1.f90
@@ -23,12 +23,12 @@ program foo
    v = cshift(c, 2)
    if (any(b /= v)) call abort
 
-   ! Special cases shift = 0, size(a), 1-size(a)
+   ! Special cases shift = 0, size(a), size(a)
    b = cshift([1, 2, 3, 4, 5], 0)
    if (any(b /= a)) call abort
    b = cshift([1, 2, 3, 4, 5], size(a))
    if (any(b /= a)) call abort
-   b = cshift([1, 2, 3, 4, 5], 1-size(a))
+   b = cshift([1, 2, 3, 4, 5], -size(a))
    if (any(b /= a)) call abort
 
    ! simplification of array arg.