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8210416: [linux] Poor StrictMath performance due to non-optimized compilation

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Compile fdlibm with -O2 -ffp-contract=off on gcc/clang arches.

Reviewed-by: aph, erikj, dholmes, darcy, ihse
This commit is contained in:
Severin Gehwolf 2018-09-17 10:53:56 +02:00
parent ee0ac147a2
commit b1375858c6
3 changed files with 21 additions and 15 deletions
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14
make/autoconf/flags-cflags.m4
View File

@ -373,6 +373,20 @@ AC_DEFUN([FLAGS_SETUP_CFLAGS],
FLAGS_SETUP_CFLAGS_CPU_DEP([BUILD], [OPENJDK_BUILD_])
COMPILER_FP_CONTRACT_OFF_FLAG="-ffp-contract=off"
# Check that the compiler supports -ffp-contract=off flag
# Set FDLIBM_CFLAGS to -ffp-contract=off if it does. Empty
# otherwise.
# These flags are required for GCC-based builds of
# fdlibm with optimization without losing precision.
# Notably, -ffp-contract=off needs to be added for GCC >= 4.6.
if test "x$TOOLCHAIN_TYPE" = xgcc || test "x$TOOLCHAIN_TYPE" = xclang; then
FLAGS_COMPILER_CHECK_ARGUMENTS(ARGUMENT: [${COMPILER_FP_CONTRACT_OFF_FLAG}],
IF_TRUE: [FDLIBM_CFLAGS=${COMPILER_FP_CONTRACT_OFF_FLAG}],
IF_FALSE: [FDLIBM_CFLAGS=""])
fi
AC_SUBST(FDLIBM_CFLAGS)
# Tests are only ever compiled for TARGET
CFLAGS_TESTLIB="$CFLAGS_JDKLIB"
CXXFLAGS_TESTLIB="$CXXFLAGS_JDKLIB"

1
make/autoconf/spec.gmk.in
View File

@ -450,6 +450,7 @@ CXXFLAGS_JDKEXE:=@CXXFLAGS_JDKEXE@
LIBJSIG_HASHSTYLE_LDFLAGS := @LIBJSIG_HASHSTYLE_LDFLAGS@
LIBJSIG_NOEXECSTACK_LDFLAGS := @LIBJSIG_NOEXECSTACK_LDFLAGS@
FDLIBM_CFLAGS := @FDLIBM_CFLAGS@
JVM_CFLAGS := @JVM_CFLAGS@
JVM_LDFLAGS := @JVM_LDFLAGS@
JVM_ASFLAGS := @JVM_ASFLAGS@

21
make/lib/CoreLibraries.gmk
View File

@ -39,20 +39,15 @@ ifeq ($(OPENJDK_TARGET_OS), solaris)
BUILD_LIBFDLIBM_OPTIMIZATION := HIGH
endif
ifeq ($(OPENJDK_TARGET_OS), linux)
ifeq ($(OPENJDK_TARGET_CPU), ppc64)
BUILD_LIBFDLIBM_OPTIMIZATION := HIGH
else ifeq ($(OPENJDK_TARGET_CPU), ppc64le)
BUILD_LIBFDLIBM_OPTIMIZATION := HIGH
else ifeq ($(OPENJDK_TARGET_CPU), s390x)
BUILD_LIBFDLIBM_OPTIMIZATION := HIGH
else ifeq ($(OPENJDK_TARGET_CPU), aarch64)
BUILD_LIBFDLIBM_OPTIMIZATION := HIGH
endif
# If FDLIBM_CFLAGS is non-empty we know that we can optimize
# fdlibm when adding those extra C flags. Currently GCC,
# and clang only.
ifneq ($(FDLIBM_CFLAGS), )
BUILD_LIBFDLIBM_OPTIMIZATION := LOW
endif
LIBFDLIBM_SRC := $(TOPDIR)/src/java.base/share/native/libfdlibm
LIBFDLIBM_CFLAGS := -I$(LIBFDLIBM_SRC)
LIBFDLIBM_CFLAGS := -I$(LIBFDLIBM_SRC) $(FDLIBM_CFLAGS)
ifneq ($(OPENJDK_TARGET_OS), macosx)
$(eval $(call SetupNativeCompilation, BUILD_LIBFDLIBM, \
@ -64,10 +59,6 @@ ifneq ($(OPENJDK_TARGET_OS), macosx)
CFLAGS := $(CFLAGS_JDKLIB) $(LIBFDLIBM_CFLAGS), \
CFLAGS_windows_debug := -DLOGGING, \
CFLAGS_aix := -qfloat=nomaf, \
CFLAGS_linux_ppc64 := -ffp-contract=off, \
CFLAGS_linux_ppc64le := -ffp-contract=off, \
CFLAGS_linux_s390x := -ffp-contract=off, \
CFLAGS_linux_aarch64 := -ffp-contract=off, \
DISABLED_WARNINGS_gcc := sign-compare misleading-indentation array-bounds, \
DISABLED_WARNINGS_microsoft := 4146 4244 4018, \
ARFLAGS := $(ARFLAGS), \