[FFmpeg-cvslog] configure: [loongson] revert no-expensive-optimizations

[Shiyou Yin]

ffmpeg | branch: master | Shiyou Yin <yinshiyou-hf at loongson.cn> | Fri Aug 24 17:22:12 2018 +0800| [e13e52fd0de68f2805e2e8a83d00ee28f9000c8a] | committer: Michael Niedermayer

configure: [loongson] revert no-expensive-optimizations

Add gcc version check before add -fno-expensive-optimizations flag.
Only when gcc version is lower than 5.3.0, this flag is needed.
More bug info see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67736
https://gcc.gnu.org/ml/gcc-patches/2012-05/msg00401.html

Signed-off-by: Shiyou Yin <yinshiyou-hf at loongson.cn>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e13e52fd0de68f2805e2e8a83d00ee28f9000c8a
---

 configure | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index 135e8cb789..3cf9412947 100755
--- a/configure
+++ b/configure
@@ -4819,15 +4819,24 @@ elif enabled mips; then
                 disable mipsfpu
                 disable mipsdsp
                 disable mipsdspr2
+                # When gcc version less than 5.3.0, add -fno-expensive-optimizations flag.
+                if [ $cc == gcc ]; then
+                    gcc_version=$(gcc -dumpversion)
+                    if [ "$(echo "$gcc_version 5.3.0" | tr " " "\n" | sort -rV | head -n 1)" == "$gcc_version" ]; then
+                        expensive_optimization_flag=""
+                    else
+                        expensive_optimization_flag="-fno-expensive-optimizations"
+                    fi
+                fi
                 case $cpu in
                     loongson3*)
-                        cpuflags="-march=loongson3a -mhard-float -fno-expensive-optimizations"
+                        cpuflags="-march=loongson3a -mhard-float $expensive_optimization_flag"
                     ;;
                     loongson2e)
-                        cpuflags="-march=loongson2e -mhard-float -fno-expensive-optimizations"
+                        cpuflags="-march=loongson2e -mhard-float $expensive_optimization_flag"
                     ;;
                     loongson2f)
-                        cpuflags="-march=loongson2f -mhard-float -fno-expensive-optimizations"
+                        cpuflags="-march=loongson2f -mhard-float $expensive_optimization_flag"
                     ;;
                 esac
             ;;