1.1 --- a/common/autoconf/flags.m4 Wed May 01 06:16:32 2019 +0100
1.2 +++ b/common/autoconf/flags.m4 Mon Apr 29 14:23:21 2019 +0200
1.3 @@ -450,6 +450,7 @@
1.4 # Later we will also have CFLAGS and LDFLAGS for the hotspot subrepo build.
1.5 #
1.6
1.7 + FDLIBM_CFLAGS=""
1.8 # Setup compiler/platform specific flags to CFLAGS_JDK,
1.9 # CXXFLAGS_JDK and CCXXFLAGS_JDK (common to C and CXX?)
1.10 if test "x$TOOLCHAIN_TYPE" = xgcc; then
1.11 @@ -474,6 +475,37 @@
1.12 ;;
1.13 esac
1.14 TOOLCHAIN_CHECK_COMPILER_VERSION(6, FLAGS_SETUP_GCC6_COMPILER_FLAGS)
1.15 +
1.16 + # Check that the compiler supports -ffp-contract=off flag
1.17 + # Set FDLIBM_CFLAGS to -ffp-contract=off if it does.
1.18 + # For GCC < 4.6, on x86, x86_64 and ppc check for
1.19 + # -mno-fused-madd and -fno-strict-aliasing. If they exist,
1.20 + # use them as a substitute for -ffp-contract=off.
1.21 + #
1.22 + # These flags are required for GCC-based builds of
1.23 + # fdlibm with optimization without losing precision.
1.24 + # Notably, -ffp-contract=off needs to be added for GCC >= 4.6,
1.25 + # -mno-fused-madd -fno-strict-aliasing for GCC < 4.6
1.26 + COMPILER_FP_CONTRACT_OFF_FLAG="-ffp-contract=off"
1.27 + FLAGS_CXX_COMPILER_CHECK_ARGUMENTS([[$]COMPILER_FP_CONTRACT_OFF_FLAG -Werror],
1.28 + [], [COMPILER_FP_CONTRACT_OFF_FLAG=""])
1.29 + if test "x$COMPILER_FP_CONTRACT_OFF_FLAG" = x; then
1.30 + if test "$OPENJDK_TARGET_CPU_ARCH" = "x86" ||
1.31 + test "$OPENJDK_TARGET_CPU_ARCH" = "x86_64" ||
1.32 + test "$OPENJDK_TARGET_CPU_ARCH" = "ppc"; then
1.33 + M_NO_FUSED_ADD_FLAG="-mno-fused-madd"
1.34 + FLAGS_CXX_COMPILER_CHECK_ARGUMENTS([[$]M_NO_FUSED_ADD_FLAG -Werror],
1.35 + [], [M_NO_FUSED_ADD_FLAG=""])
1.36 + NO_STRICT_ALIASING_FLAG="-fno-strict-aliasing"
1.37 + FLAGS_CXX_COMPILER_CHECK_ARGUMENTS([[$]NO_STRICT_ALIASING_FLAG -Werror],
1.38 + [], [NO_STRICT_ALIASING_FLAG=""])
1.39 + if test "x$M_NO_FUSED_ADD_FLAG" != "x" && test "x$NO_STRICT_ALIASING_FLAG" != "x"; then
1.40 + FDLIBM_CFLAGS="$M_NO_FUSED_ADD_FLAG $NO_STRICT_ALIASING_FLAG"
1.41 + fi
1.42 + fi
1.43 + else
1.44 + FDLIBM_CFLAGS="$COMPILER_FP_CONTRACT_OFF_FLAG"
1.45 + fi
1.46 elif test "x$TOOLCHAIN_TYPE" = xsolstudio; then
1.47 CCXXFLAGS_JDK="$CCXXFLAGS $CCXXFLAGS_JDK -DTRACING -DMACRO_MEMSYS_OPS -DBREAKPTS"
1.48 if test "x$OPENJDK_TARGET_CPU_ARCH" = xx86; then
1.49 @@ -505,6 +537,7 @@
1.50 -D_STATIC_CPPLIB -D_DISABLE_DEPRECATE_STATIC_CPPLIB"
1.51 fi
1.52 fi
1.53 + AC_SUBST(FDLIBM_CFLAGS)
1.54
1.55 ###############################################################################
1.56
