swr: switch from overriding -march to selecting features

Acked-by: Chuck Atkins <chuck.atkins@kitware.com>
Tested-by: Chuck Atkins <chuck.atkins@kitware.com>
(cherry picked from commit 5a64549f54)

configure.ac

@@ -2402,8 +2402,8 @@ if test -n "$with_gallium_drivers"; then
             swr_llvm_check "swr"
 
             AC_MSG_CHECKING([whether $CXX supports c++11/AVX/AVX2])
-            AVX_CXXFLAGS="-march=core-avx-i"
-            AVX2_CXXFLAGS="-march=core-avx2"
+            SWR_AVX_CXXFLAGS="-mavx"
+            SWR_AVX2_CXXFLAGS="-mavx2 -mfma -mbmi2 -mf16c"
 
             AC_LANG_PUSH([C++])
             save_CXXFLAGS="$CXXFLAGS"
@@ -2413,18 +2413,21 @@ if test -n "$with_gallium_drivers"; then
             CXXFLAGS="$save_CXXFLAGS"
 
             save_CXXFLAGS="$CXXFLAGS"
-            CXXFLAGS="$AVX_CXXFLAGS $CXXFLAGS"
+            CXXFLAGS="$SWR_AVX_CXXFLAGS $CXXFLAGS"
             AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
                               [AC_MSG_ERROR([AVX compiler support not detected])])
             CXXFLAGS="$save_CXXFLAGS"
 
             save_CFLAGS="$CXXFLAGS"
-            CXXFLAGS="$AVX2_CXXFLAGS $CXXFLAGS"
+            CXXFLAGS="$SWR_AVX2_CXXFLAGS $CXXFLAGS"
             AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
                               [AC_MSG_ERROR([AVX2 compiler support not detected])])
             CXXFLAGS="$save_CXXFLAGS"
             AC_LANG_POP([C++])
 
+            AC_SUBST([SWR_AVX_CXXFLAGS])
+            AC_SUBST([SWR_AVX2_CXXFLAGS])
+
             HAVE_GALLIUM_SWR=yes
             ;;
         xvc4)

src/gallium/drivers/swr/Makefile.am

@@ -148,7 +148,7 @@ distclean-local:
 lib_LTLIBRARIES = libswrAVX.la libswrAVX2.la
 
 libswrAVX_la_CXXFLAGS = \
-	-march=core-avx-i \
+	$(SWR_AVX_CXXFLAGS) \
 	-DKNOB_ARCH=KNOB_ARCH_AVX \
 	$(COMMON_CXXFLAGS)
 
@@ -171,7 +171,7 @@ libswrAVX_la_LDFLAGS = \
 	$(COMMON_LDFLAGS)
 
 libswrAVX2_la_CXXFLAGS = \
-	-march=core-avx2 \
+	$(SWR_AVX2_CXXFLAGS) \
 	-DKNOB_ARCH=KNOB_ARCH_AVX2 \
 	$(COMMON_CXXFLAGS)