Merge fixes and code reconciliation wit develop

4 files changed, 297 insertions, 367 deletions

diff --git a/config/cmake/HDFCompilerFlags.cmake b/config/cmake/HDFCompilerFlags.cmake
index 0a39568..82d63af 100644
--- a/config/cmake/HDFCompilerFlags.cmake
+++ b/config/cmake/HDFCompilerFlags.cmake
@@ -195,7 +195,22 @@ if (NOT MSVC AND CMAKE_COMPILER_IS_GNUCC)
 
     # Append more extra warning flags that only gcc 6.x+ know about
     if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 6.0)
-      set (H5_CFLAGS4 "${H5_CFLAGS4} -Wnull-dereference -Wunused-const-variable -Wduplicated-cond -Whsa")
+      set (H5_CFLAGS4 "${H5_CFLAGS4} -Wnull-dereference -Wunused-const-variable -Wduplicated-cond -Whsa -Wnormalized")
+    endif ()
+
+    # Append more extra warning flags that only gcc 7.x+ know about
+    if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 7.0)
+      set (H5_CFLAGS4 "${H5_CFLAGS4} -Walloc-zero -Walloca -Wduplicated-branches -Wformat-overflow=2 -Wformat-truncation=2 -Wimplicit-fallthrough=5 -Wrestrict")
+    endif ()
+
+    # Append more extra warning flags that only gcc 8.x+ know about
+    if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 8.0)
+      set (H5_CFLAGS4 "${H5_CFLAGS4} -Wattribute-alias -Wcast-align=strict -Wshift-overflow=2 -Wno-suggest-attribute=cold -Wno-suggest-attribute=malloc")
+    endif ()
+
+    # Append more extra warning flags that only gcc 9.x+ know about
+    if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 9.0)
+      set (H5_CFLAGS4 "${H5_CFLAGS4} Wattribute-alias=2 -Wmissing-profile")
     endif ()
 
 endif ()
diff --git a/config/conclude.am b/config/conclude.am
index 27cd7ee..6e96ba2 100644
--- a/config/conclude.am
+++ b/config/conclude.am
@@ -68,7 +68,7 @@ all-local: $(EXTRA_LIB) $(EXTRA_PROG) $(chk_TESTS)
 # make install-doc doesn't do anything outside of doc directory, but
 # Makefiles should recognize it.
 # UPDATE: docs no longer reside in this build tree, so this target
-# is depreciated.
+# is deprecated.
 install-doc uninstall-doc:
 	@echo "Nothing to be done."
 
diff --git a/config/gnu-fflags b/config/gnu-fflags
index 6b5e6a1..3fc112d 100644
--- a/config/gnu-fflags
+++ b/config/gnu-fflags
@@ -1,4 +1,4 @@
-#							-*- shell-script -*-
+#                            -*- shell-script -*-
 #
 # Copyright by The HDF Group.
 # Copyright by the Board of Trustees of the University of Illinois.
@@ -25,9 +25,8 @@
 #
 if test X = "X$f9x_flags_set"; then
     f9x_version="`$FC $FCFLAGS $H5_FCFLAGS -v 2>&1 |grep 'gcc version' |\
-	        sed 's/.*gcc version \([-a-z0-9\.]*\).*/\1/'`"
+            sed 's/.*gcc version \([-a-z0-9\.]*\).*/\1/'`"
     if test X != "X$f9x_version"; then
-#        is_mpi="`$FC $FCFLAGS $H5_FCFLAGS -help 2>&1 |grep 'link MPI'`"
         f9x_vendor=`echo $f9x_version |sed 's/\([a-z]*\).*/\1/'`
         f9x_version=`echo $f9x_version |sed 's/[-a-z]//g'`
         if test X = "X$f9x_vendor" -a X != "X$f9x_version"; then
@@ -37,24 +36,38 @@ if test X = "X$f9x_flags_set"; then
             echo "compiler '$FC' is GNU $f9x_vendor-$f9x_version"
         fi
 
-        # Some version numbers
+        # Get the compiler version numbers
         f9x_vers_major=`echo $f9x_version | cut -f1 -d.`
         f9x_vers_minor=`echo $f9x_version | cut -f2 -d.`
         f9x_vers_patch=`echo $f9x_version | cut -f3 -d.`
         test -n "$f9x_vers_major" || f9x_vers_major=0
         test -n "$f9x_vers_minor" || f9x_vers_minor=0
         test -n "$f9x_vers_patch" || f9x_vers_patch=0
-        f9x_vers_all=`expr $f9x_vers_major '*' 1000000 + $f9x_vers_minor '*' 1000 + $f9x_vers_patch`
     fi
 fi
 
-# Common GNU flags for various situations
 if test "X-gfortran" = "X-$f9x_vendor"; then
-    # Insert section about version specific problems from gnu-flags here, if
-    # necessary.
+
+    FC_BASENAME=gfortran
+    F9XSUFFIXFLAG=""
+    FSEARCH_DIRS=""
+
+    # Need Fortran 2008 support for storage_size() in gcc 4.6 on
+    # (2008ts in some versions)
+    if test $f9x_vers_major -ge 8; then
+        H5_FCFLAGS="$H5_FCFLAGS -std=f2008"
+    elif test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 6; then
+        H5_FCFLAGS="$H5_FCFLAGS -std=f2008ts"
+    else
+        H5_FCFLAGS="$H5_FCFLAGS -std=f2003"
+    fi
+
+
+    ###############################
+    # Architecture-specific flags #
+    ###############################
 
     arch=
-    # Architecture-specific flags
     # Nothing currently. (Uncomment code below and modify to add any)
     #case "$host_os-$host_cpu" in
     #    *-i686)
@@ -62,43 +75,116 @@ if test "X-gfortran" = "X-$f9x_vendor"; then
     #        ;;
     #esac
 
-    # Host-specific flags
-    # Nothing currently. (Uncomment code below and modify to add any)
-    #case "`hostname`" in
-    #    sleipnir.ncsa.uiuc.edu)
-    #        arch="$arch -pipe"
-    #        ;;
-    #esac
+    H5_FCFLAGS="$H5_FCFLAGS $arch"
 
-    # General
-    FC_BASENAME=gfortran
-    F9XSUFFIXFLAG=""
-    FSEARCH_DIRS=""
-    H5_FCFLAGS="$H5_FCFLAGS -pedantic -Wall -Wextra -Wunderflow -Wimplicit-interface -Wsurprising"
+    ##############
+    # Production #
+    ##############
 
-    # Turn off warnings for passing non-ANSI types to BIND().
-    # We pass a lot of hid_t, etc. types so this generates a LOT of spurious warnings.
-    H5_FCFLAGS="$H5_FCFLAGS -Wno-c-binding-type"
-
-    # Production
     PROD_FCFLAGS=
 
-    # Debug
-    DEBUG_FCFLAGS="-fbounds-check"
+    #########
+    # Debug #
+    #########
+
+    if test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 5; then
+        DEBUG_FCFLAGS="-fcheck=all"
+    else
+        DEBUG_FCFLAGS="-fbounds-check"
+    fi
+
+    ###########
+    # Symbols #
+    ###########
 
-    # Symbols
     SYMBOLS_FCFLAGS="-g"
     NO_SYMBOLS_FCFLAGS="-s"
 
-    # Profiling
+    #############
+    # Profiling #
+    #############
+
     PROFILE_FCFLAGS="-pg"
 
-    # Optimization
-    HIGH_OPT_FCFLAGS="-O2"
-    DEBUG_OPT_FCFLAGS="-O0"
+    ################
+    # Optimization #
+    ################
+
+    if test $f9x_vers_major -le 4; then
+        HIGH_OPT_FCFLAGS="-O3"
+        DEBUG_OPT_FCFLAGS=
+    else
+        HIGH_OPT_FCFLAGS="-O3"
+        DEBUG_OPT_FCFLAGS="-Og"
+    fi
     NO_OPT_FCFLAGS="-O0"
 
-    # Flags are set
+    ############
+    # Warnings #
+    ############
+
+    ###########
+    # General #
+    ###########
+
+    H5_FCFLAGS="$H5_FCFLAGS -pedantic -Wall -Wextra -Wunderflow -Wimplicit-interface -Wsurprising"
+    H5_FCFLAGS="$H5_FCFLAGS -Waliasing -Wcharacter-truncation"
+
+    #############################
+    # Version-specific warnings #
+    #############################
+
+    # gfortran 4.3 (nothing new)
+
+    # gfortran 4.4
+    if test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 4; then
+        H5_FCFLAGS="$H5_FCFLAGS -Warray-temporaries -Wintrinsics-std"
+    fi
+
+    # gfortran 4.5
+    if test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 5; then
+        H5_FCFLAGS="$H5_FCFLAGS -Wimplicit-procedure"
+    fi
+
+    # gfortran 4.6 (nothing new)
+
+    # gfortran 4.7
+    if test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 7; then
+        H5_FCFLAGS="$H5_FCFLAGS -Wreal-q-constant -Wfunction-elimination"
+    fi
+
+    # gfortran 4.8
+    if test $f9x_vers_major -ge 5 -o $f9x_vers_major -eq 4 -a $f9x_vers_minor -ge 8; then
+        H5_FCFLAGS="$H5_FCFLAGS -Wrealloc-lhs -Wrealloc-lhs-all"
+        # Turn off warnings for passing non-ANSI types to BIND().
+        # We pass a lot of hid_t, etc. types so this generates a LOT of spurious warnings.
+        H5_FCFLAGS="$H5_FCFLAGS -Wno-c-binding-type"
+    fi
+
+    # gfortran 4.9 (nothing new)
+
+    # gfortran 5
+    if test $f9x_vers_major -ge 5; then
+        H5_FCFLAGS="$H5_FCFLAGS -Wuse-without-only"
+    fi
+
+    # gfortran 6
+    if test $f9x_vers_major -ge 6; then
+        H5_FCFLAGS="$H5_FCFLAGS -Winteger-division"
+    fi
+
+    # gfortran 7 (nothing new)
+
+    # gfortran 8
+    if test $f9x_vers_major -ge 8; then
+        H5_FCFLAGS="$H5_FCFLAGS -Wfrontend-loop-interchange"
+    fi
+
+    # gfortran 9 (nothing new)
+
+    #################
+    # Flags are set #
+    #################
     f9x_flags_set=yes
 fi
 
diff --git a/config/gnu-flags b/config/gnu-flags
index 7df72c7..6355ccf 100644
--- a/config/gnu-flags
+++ b/config/gnu-flags
@@ -14,7 +14,7 @@
 
 # This file should be sourced into configure if the compiler is the
 # GNU gcc compiler or a derivative.  It is careful not to do anything
-# if the compiler is not GNU; otherwise `cc_flags_set' is set to `yes'
+# if the compiler is not GNU; otherwise 'cc_flags_set' is set to 'yes'
 #
 
 # Get the compiler version in a way that works for gcc
@@ -23,7 +23,7 @@
 #   cc_vendor:    The compiler name: gcc
 #   cc_version:   Version number: 2.91.60, 2.7.2.1
 #
-if test X = "X$cc_flags_set"; then
+if test "X-" = "X-$cc_flags_set"; then
     # PathScale compiler spits out gcc version string too. Need to
     # filter it out.
     # icc beginning with version 12 includes a "gcc version compatiblilty"
@@ -37,26 +37,27 @@ if test X = "X$cc_flags_set"; then
     cc_vendor=`echo $cc_version |sed 's/\([a-z]*\).*/\1/'`
     cc_version=`echo $cc_version |sed 's/[-a-z]//g'`
     if test X = "X$cc_vendor" -a X != "X$cc_version"; then
-    cc_vendor=gcc
+        cc_vendor=gcc
     fi
     if test "-" != "$cc_vendor-$cc_version"; then
-    echo "compiler '$CC' is GNU $cc_vendor-$cc_version"
+        echo "compiler '$CC' is GNU $cc_vendor-$cc_version"
     fi
 
-    # Some version numbers
+    # Get the compiler version numbers
     cc_vers_major=`echo $cc_version | cut -f1 -d.`
     cc_vers_minor=`echo $cc_version | cut -f2 -d.`
     cc_vers_patch=`echo $cc_version | cut -f3 -d.`
     test -n "$cc_vers_major" || cc_vers_major=0
     test -n "$cc_vers_minor" || cc_vers_minor=0
     test -n "$cc_vers_patch" || cc_vers_patch=0
-    cc_vers_all=`expr $cc_vers_major '*' 1000000 + $cc_vers_minor '*' 1000 + $cc_vers_patch`
 fi
 
-# Common GCC flags for various situations
-case "$cc_vendor-$cc_version" in
-  gcc*)
-    # Architecture-specific flags
+if test "X-gcc" = "X-$cc_vendor"; then
+
+    ###############################
+    # Architecture-specific flags #
+    ###############################
+
     arch=
     case "$host_os-$host_cpu" in
         # FreeBSD sets the information from "uname -m" to the general machine
@@ -96,377 +97,205 @@ case "$cc_vendor-$cc_version" in
             ;;
     esac
 
-    # Host-specific flags
-    case "`hostname`" in
-        sleipnir.ncsa.uiuc.edu)
-            arch="$arch -pipe"
-            ;;
-    esac
+    H5_CFLAGS="$H5_CFLAGS $arch"
 
-    # General flags
-    #
-    # Note that some of the flags listed here really should be developer
-    # flags (listed in a separate variable, below) but we put them here
-    # because they are not raised by the current code and we'd like to
-    # know if they do start showing up.
-    #
-    # NOTE: Don't add -Wpadded here since we can't/won't fix the (many)
-    # warnings that are emitted. If you need it, add it from the
-    # environment variable at configure time.
-    H5_CFLAGS="$H5_CFLAGS $arch -pedantic -Wall -Wextra -Wbad-function-cast -Wc++-compat -Wcast-align"
-    H5_CFLAGS="$H5_CFLAGS -Wcast-qual -Wconversion -Wdeclaration-after-statement -Wdisabled-optimization -Wfloat-equal"
-    H5_CFLAGS="$H5_CFLAGS -Wformat=2 -Winit-self -Winvalid-pch -Wmissing-declarations -Wmissing-include-dirs"
-    H5_CFLAGS="$H5_CFLAGS -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wpacked -Wpointer-arith"
-    H5_CFLAGS="$H5_CFLAGS -Wredundant-decls -Wshadow -Wstrict-prototypes -Wswitch-default -Wswitch-enum"
-    H5_CFLAGS="$H5_CFLAGS -Wundef -Wunused-macros -Wunsafe-loop-optimizations -Wwrite-strings"
+    ##############
+    # Production #
+    ##############
 
-    # Production
     # NDEBUG is handled explicitly by the configure script
-    case "$cc_vendor-$cc_version" in
-      gcc-4.*)
+    if test $cc_vers_major -le 4; then
         PROD_CFLAGS=
-        ;;
-      gcc-[56789].*)
+    else
         PROD_CFLAGS="-fstdarg-opt"
-        ;;
-      *)
-        # gcc automatically inlines based on the optimization level
-        # this is just a failsafe
-        PROD_CFLAGS="-finline-functions"
-        ;;
-    esac
+    fi
+
+    #########
+    # Debug #
+    #########
 
-    # Debug
     # NDEBUG is handled explicitly by the configure script
     # -g is handled by the symbols flags
-    case "$cc_vendor-$cc_version" in
-      gcc-[56789].*)
-        DEBUG_CFLAGS="-ftrapv -fno-common"
-        ;;
-      *)
+    if test $cc_vers_major -le 4; then
         DEBUG_CFLAGS=
-        ;;
-    esac
+    else
+        DEBUG_CFLAGS="-ftrapv -fno-common"
+    fi
 
-    # Developer warnings (suggestions from gcc, not code problems)
-    DEVELOPER_WARNING_CFLAGS="-Winline -Waggregate-return -Wmissing-format-attribute -Wmissing-noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="-Wno-inline -Wno-aggregate-return -Wno-missing-format-attribute -Wno-missing-noreturn"
+    ###########
+    # Symbols #
+    ###########
 
-    # Symbols
     NO_SYMBOLS_CFLAGS="-s"
     SYMBOLS_CFLAGS="-g -fno-omit-frame-pointer"
 
-    # Profile
+    #############
+    # Profiling #
+    #############
+
     PROFILE_CFLAGS="-pg"
 
-    # Optimization
-    case "$cc_vendor-$cc_version" in
-      gcc-4.*)
+    ################
+    # Optimization #
+    ################
+    
+    if test $cc_vers_major -le 4; then
         HIGH_OPT_CFLAGS="-O3"
         DEBUG_OPT_CFLAGS=
-        ;;
-      gcc-[56789].*)
+    else
         HIGH_OPT_CFLAGS="-O3"
         DEBUG_OPT_CFLAGS="-Og"
-        ;;
-      *)
-        HIGH_OPT_CFLAGS="-O"
-        DEBUG_OPT_CFLAGS=
-        ;;
-    esac
+    fi
     NO_OPT_CFLAGS="-O0"
 
-    # Flags are set
-    cc_flags_set=yes
-    ;;
-esac
-
-# Version specific GCC flags
-#
-# Please follow the pattern below by adding new versions at the top, copying
-# the information from the previous version and adding modifications to that.
-case "$cc_vendor-$cc_version" in
-
-# When the gcc 7.x release is out, we should check for additional flags to
-# include and break it out into it's own section, like the other versions
-# below. -QAK
-  gcc-[6789].*)
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
-
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
-
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
-
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-
-    # Append warning flags that only gcc 4.7+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
-
-    # Append warning flags that only gcc 4.8+ knows about
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=format"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=format"
-
-    # Append warning flags that only gcc 4.9+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdate-time"
-
-    # Append warning flags that only gcc 5.x+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Warray-bounds=2 -Wc99-c11-compat"
-
-    # Append warning flags that only gcc 6.x+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wnull-dereference -Wunused-const-variable -Wduplicated-cond -Whsa"
-    ;;
-
-  gcc-5*)
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
-
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
-
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
-
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-
-    # Append warning flags that only gcc 4.7+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
-
-    # Append warning flags that only gcc 4.8+ knows about
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=format"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=format"
-
-    # Append warning flags that only gcc 4.9+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdate-time"
-
-    # Append warning flags that only gcc 5.x+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Warray-bounds=2 -Wc99-c11-compat"
-    ;;
-
-  gcc-4.9*)
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
-
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
-
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
-
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-
-    # Append warning flags that only gcc 4.7+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
-
-    # Append warning flags that only gcc 4.8+ knows about
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=format"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=format"
-
-    # Append warning flags that only gcc 4.9+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdate-time"
-    ;;
+    ############
+    # Warnings #
+    ############
 
-  gcc-4.8*)
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
+    ###########
+    # General #
+    ###########
 
-    # Append warning flags that only gcc 4.3+ knows about
+    # Note that some of the flags listed here really should be developer
+    # flags (listed in a separate variable, below) but we put them here
+    # because they are not raised by the current code and we'd like to
+    # know if they do start showing up.
     #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
-
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init"
-
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-
-    # Append warning flags that only gcc 4.7+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
-
-    # Append warning flags that only gcc 4.8+ knows about
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=format"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=format"
-    ;;
-
-  gcc-4.7*)
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
-
-    # Append warning flags that only gcc 4.3+ knows about
+    # NOTE: Don't add -Wpadded here since we can't/won't fix the (many)
+    # warnings that are emitted. If you need it, add it from the
+    # environment variable at configure time.
     #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
-
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
-
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-
-    # Append warning flags that only gcc 4.7+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
-    ;;
-
-  gcc-4.6*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
-
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
-
-    # Append warning flags that only gcc 4.3+ knows about
+    # NOTE: Disable the -Wformat-nonliteral from -Wformat=2 here and re-add
+    # it to the developer flags.
     #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
+    H5_CFLAGS="$H5_CFLAGS -pedantic -Wall -Wextra -Wbad-function-cast -Wc++-compat -Wcast-align"
+    H5_CFLAGS="$H5_CFLAGS -Wcast-qual -Wconversion -Wdeclaration-after-statement -Wdisabled-optimization -Wfloat-equal"
+    H5_CFLAGS="$H5_CFLAGS -Wformat=2 -Wno-format-nonliteral -Winit-self -Winvalid-pch -Wmissing-declarations -Wmissing-include-dirs"
+    H5_CFLAGS="$H5_CFLAGS -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wpacked"
+    H5_CFLAGS="$H5_CFLAGS -Wredundant-decls -Wshadow -Wstrict-prototypes -Wswitch-enum -Wswitch-default"
+    H5_CFLAGS="$H5_CFLAGS -Wundef -Wunused-macros -Wunsafe-loop-optimizations -Wwrite-strings"
 
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
+    ######################
+    # Developer warnings #
+    ######################
 
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-aliasing -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
+    # (suggestions from gcc, not code problems)
+    # NOTE: -Wformat-nonliteral added back in here (from being disabled in H5_CFLAGS)
+    DEVELOPER_WARNING_CFLAGS="-Winline -Waggregate-return -Wmissing-format-attribute -Wmissing-noreturn -Wformat-nonliteral"
+    NO_DEVELOPER_WARNING_CFLAGS="-Wno-inline -Wno-aggregate-return -Wno-missing-format-attribute -Wno-missing-noreturn"
 
-    # Append warning flags that only gcc 4.6+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
-    DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
-    NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
-    ;;
+    #######################
+    # gcc 4 special cases #
+    #######################
 
-  gcc-4.5*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    # Disable warnings about using the 'long long' type w/ gcc 4.6 and earlier
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 6; then
+        H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    fi
 
-    # Append warning flags that only gcc 4.2+ knows about
-    # (none, or incorporated in -Wall / -Wextra now)
+    # -Wvolatile-register-var was later incorporated into -Wall and              
+    # only needs to be specified explicitly for gcc 4.2-4.3                      
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 3; then
+        H5_CFLAGS="$H5_CFLAGS -Wvolatile-register-var"                           
+    fi 
 
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
+    # -Wstrict-aliasing was later incorporated into -Wall and
+    # only needs to be specified explicitly for gcc 4.5-4.6
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 6; then
+        H5_CFLAGS="$H5_CFLAGS -Wstrict-aliasing"
+    fi
 
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
+    # The non-valued form of -Wstrict-overflow is used in gcc 4.2-4.4
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -a $cc_vers_major -eq 4 -a $cc_vers_minor -le 4; then
+        H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow"
+    fi
 
-    # Append warning flags that only gcc 4.5+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-aliasing -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
-    ;;
+    # -Wvla was later incorporated into -Wpedantic and
+    # only needs to be specified explicitly for gcc 4
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2; then
+        H5_CFLAGS="$H5_CFLAGS -Wvla"
+    fi
 
-  gcc-4.4*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    #############################
+    # Version-specific warnings #
+    #############################
 
-    # Append warning flags that only gcc 4.2+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow"
+    # gcc 4.3                                                                    
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 3; then
+        H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2560"                   
+    fi 
 
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wlarger-than=2048 -Wvla"
+    # gcc 4.4
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 4; then
+        H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
+    fi
 
-    # Append warning flags that only gcc 4.4+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wsync-nand -Wframe-larger-than=16384 -Wpacked-bitfield-compat"
-    ;;
+    # gcc 4.5
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 5; then
+        H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow=5 -Wjump-misses-init -Wunsuffixed-float-constants"
+    fi
 
-  gcc-4.3*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    # gcc 4.6
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 6; then
+        H5_CFLAGS="$H5_CFLAGS -Wdouble-promotion -Wtrampolines"
+        DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=const"
+        NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=const"
+    fi
 
-    # Append warning flags that only gcc 4.1+ knows about
-    # -Wvolatile-register-var was later incorporated into -Wall and
-    # needs to be specified explicitly for gcc 4.1-4.3.
-    H5_CFLAGS="$H5_CFLAGS -Wvolatile-register-var"
+    # gcc 4.7
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 7; then
+        H5_CFLAGS="$H5_CFLAGS -Wstack-usage=8192 -Wvector-operation-performance"
+        DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=pure -Wsuggest-attribute=noreturn"
+        NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=pure -Wno-suggest-attribute=noreturn"
+    fi
 
-    # Append warning flags that only gcc 4.2+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow"
+    # gcc 4.8
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 8; then
+        DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wsuggest-attribute=format"
+        NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=format"
+    fi
 
-    # Append warning flags that only gcc 4.3+ knows about
-    #
-    # Technically, variable-length arrays are part of the C99 standard, but
-    #   we should approach them a bit cautiously... -QAK
-    H5_CFLAGS="$H5_CFLAGS -Wlogical-op -Wvla"
-    ;;
+    # gcc 4.9
+    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 9; then
+        H5_CFLAGS="$H5_CFLAGS -Wdate-time"
+    fi
 
-  gcc-4.2*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    # gcc 5
+    if test $cc_vers_major -ge 5; then
+        H5_CFLAGS="$H5_CFLAGS -Warray-bounds=2 -Wc99-c11-compat"
+    fi
 
-    # Append warning flags that only gcc 4.1+ knows about
-    # -Wvolatile-register-var was later incorporated into -Wall and
-    # needs to be specified explicitly for gcc 4.1-4.3.
-    H5_CFLAGS="$H5_CFLAGS -Wvolatile-register-var"
+    # gcc 6
+    if test $cc_vers_major -ge 6; then
+        H5_CFLAGS="$H5_CFLAGS -Wnull-dereference -Wunused-const-variable -Wduplicated-cond -Whsa -Wnormalized"
+    fi
 
-    # Append warning flags that only gcc 4.2+ knows about
-    H5_CFLAGS="$H5_CFLAGS -Wstrict-overflow"
-    ;;
+    # gcc 7
+    if test $cc_vers_major -ge 7; then
+        DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wstringop-overflow=2"
+        H5_CFLAGS="$H5_CFLAGS -Walloc-zero -Walloca -Wduplicated-branches -Wformat-overflow=2 -Wformat-truncation=2 -Wimplicit-fallthrough=5 -Wrestrict"
+    fi
 
-  gcc-4.1*)
-    # Disable warnings about using 'long long' type
-    H5_CFLAGS="$H5_CFLAGS -Wno-long-long"
+    # gcc 8
+    if test $cc_vers_major -ge 8; then
+        DEVELOPER_WARNING_CFLAGS="$DEVELOPER_WARNING_CFLAGS -Wstringop-overflow=4 -Wsuggest-attribute=cold -Wsuggest-attribute=malloc"
+        NO_DEVELOPER_WARNING_CFLAGS="$NO_DEVELOPER_WARNING_CFLAGS -Wno-suggest-attribute=cold -Wno-suggest-attribute=malloc"
+        H5_CFLAGS="$H5_CFLAGS -Wattribute-alias -Wcast-align=strict -Wshift-overflow=2"
+    fi
 
-    # Append warning flags that only gcc 4.1+ knows about
-    # -Wvolatile-register-var was later incorporated into -Wall and
-    # needs to be specified explicitly for gcc 4.1-4.3.
-    H5_CFLAGS="$H5_CFLAGS -Wvolatile-register-var"
-    ;;
+    # gcc 9
+    if test $cc_vers_major -ge 9; then
+        H5_CFLAGS="$H5_CFLAGS -Wattribute-alias=2 -Wmissing-profile"
+    fi
 
-esac
+    #################
+    # Flags are set #
+    #################
+    cc_flags_set=yes
+fi
 
 # Clear cc info if no flags set
 if test "X$cc_flags_set" = "X"; then
-  cc_vendor=
-  cc_version=
+    cc_vendor=
+    cc_version=
 fi