diff --git a/contrib/ChangeLog b/contrib/ChangeLog
index ea346590548..1f02d959496 100644
--- a/contrib/ChangeLog
+++ b/contrib/ChangeLog
@@ -1,3 +1,9 @@
+2015-01-12  Yury Gribov  <y.gribov@samsung.com>
+
+	* check_GNU_style.sh: Support patches coming from stdin.
+	Check that spaces are converted to tabs.
+	Make double-space-after-dot check more precice.
+
 2015-01-06  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config-list.mk (LIST): Add visium-elf.
diff --git a/contrib/check_GNU_style.sh b/contrib/check_GNU_style.sh
index aed90b4e3a5..e8d5dcaf7bc 100755
--- a/contrib/check_GNU_style.sh
+++ b/contrib/check_GNU_style.sh
@@ -23,6 +23,8 @@ usage() {
 check_GNU_style.sh [patch]...
 
     Checks the patches for some of the GNU style formatting problems.
+    When FILE is -, read standard input.
+
     Please note that these checks are not always accurate, and
     complete.  The reference documentation of the GNU Coding Standards
     can be found here: http://www.gnu.org/prep/standards_toc.html
@@ -35,19 +37,22 @@ EOF
 
 test $# -eq 0 && usage
 
+inp=check_GNU_style.inp
 tmp=check_GNU_style.tmp
 
 # Remove $tmp on exit and various signals.
-trap "rm -f $tmp" 0
-trap "rm -f $tmp ; exit 1" 1 2 3 5 9 13 15
+trap "rm -f $inp $tmp" 0
+trap "rm -f $inp $tmp ; exit 1" 1 2 3 5 9 13 15
+
+grep -nH '^+' $* \
+	| grep -v ':+++' \
+	> $inp
 
 # Grep
 g (){
     msg="$1"
     arg="$2"
-    shift 2
-    grep -nH '^+' $* \
-	| grep -v ':+++' \
+    cat $inp \
 	| egrep --color=always -- "$arg" \
 	> $tmp && printf "\n$msg\n"
     cat $tmp
@@ -58,9 +63,7 @@ ag (){
     msg="$1"
     arg1="$2"
     arg2="$3"
-    shift 3
-    grep -nH '^+' $* \
-	| grep -v ':+++' \
+    cat $inp \
 	| egrep --color=always -- "$arg1" \
 	| egrep --color=always -- "$arg2" \
 	> $tmp && printf "\n$msg\n"
@@ -72,9 +75,7 @@ vg (){
     msg="$1"
     varg="$2"
     arg="$3"
-    shift 3
-    grep -nH '^+' $* \
-	| grep -v ':+++' \
+    cat $inp \
 	| egrep -v -- "$varg" \
 	| egrep --color=always -- "$arg" \
 	> $tmp && printf "\n$msg\n"
@@ -83,9 +84,7 @@ vg (){
 
 col (){
     msg="$1"
-    shift 1
-    grep -nH '^+' $* \
-	| grep -v ':+++' \
+    cat $inp \
 	| awk -F':\\+' '{ if (length($2) > 80) print $0}' \
 	> $tmp
     if [ -s $tmp ]; then
@@ -94,30 +93,32 @@ col (){
     fi
 }
 
-col 'Lines should not exceed 80 characters.' $*
+col 'Lines should not exceed 80 characters.'
+
+g 'Blocks of 8 spaces should be replaced with tabs.' \
+    ' {8}'
 
 g 'Trailing whitespace.' \
-    '[[:space:]]$' $*
+    '[[:space:]]$'
 
 g 'Space before dot.' \
-    '[[:alnum:]][[:blank:]]+\.' $*
+    '[[:alnum:]][[:blank:]]+\.'
 
 g 'Dot, space, space, new sentence.' \
-    '[[:alnum:]]\.([[:blank:]]|[[:blank:]]{3,})[[:alnum:]]' $*
+    '[[:alnum:]]\.([[:blank:]]|[[:blank:]]{3,})[A-Z0-9]'
 
 g 'Dot, space, space, end of comment.' \
-    '[[:alnum:]]\.([[:blank:]]{0,1}|[[:blank:]]{3,})\*/' $*
+    '[[:alnum:]]\.([[:blank:]]{0,1}|[[:blank:]]{3,})\*/'
 
 g 'Sentences should end with a dot.  Dot, space, space, end of the comment.' \
-    '[[:alnum:]][[:blank:]]*\*/' $*
+    '[[:alnum:]][[:blank:]]*\*/'
 
 vg 'There should be exactly one space between function name and parentheses.' \
-    '\#define' '[[:alnum:]]([[:blank:]]{2,})?\(' $*
+    '\#define' '[[:alnum:]]([[:blank:]]{2,})?\('
 
 g 'There should be no space before closing parentheses.' \
-    '[[:graph:]][[:blank:]]+\)' $*
+    '[[:graph:]][[:blank:]]+\)'
 
 ag 'Braces should be on a separate line.' \
-    '\{' 'if[[:blank:]]\(|while[[:blank:]]\(|switch[[:blank:]]\(' $*
-
+    '\{' 'if[[:blank:]]\(|while[[:blank:]]\(|switch[[:blank:]]\('