Optimize FT_MulFix for x86_64 GCC builds.
This patch provides an optimized `FT_MulFix' implementation for x86_64 machines when FreeType is built with GCC, or compatible compilers like Clang. Example: bin/ftbench -p -t 5 -s 14 -f 0008 Arial.ttf Before: Load 4.863 us/op Load_Advances (Normal) 4.816 us/op Load_Advances (Fast) 0.028 us/op Render 2.753 us/op Get_Glyph 0.463 us/op Get_CBox 0.077 us/op Get_Char_Index 0.023 us/op Iterate CMap 13.898 us/op New_Face 12.368 us/op Embolden 0.028 us/op Get_BBox 0.302 us/op After: Load 4.617 us/op Load_Advances (Normal) 4.645 us/op Load_Advances (Fast) 0.027 us/op Render 2.789 us/op Get_Glyph 0.460 us/op Get_CBox 0.077 us/op Get_Char_Index 0.024 us/op Iterate CMap 13.403 us/op New_Face 12.278 us/op Embolden 0.028 us/op Get_BBox 0.301 us/op * builds/unix/ftconfig.in, include/freetype/config/ftconfig.h (FT_MulFix_x86_64): New function.
This commit is contained in:
David Turner
Werner Lemberg
parent
a5f33eeb8a
commit
b28908860d
42
ChangeLog
42
ChangeLog
@ -1,3 +1,45 @@
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2013-07-16 David Turner <digit@google.com>
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Optimize FT_MulFix for x86_64 GCC builds.
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This patch provides an optimized `FT_MulFix' implementation for
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x86_64 machines when FreeType is built with GCC, or compatible
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compilers like Clang.
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Example:
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bin/ftbench -p -t 5 -s 14 -f 0008 Arial.ttf
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Before:
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Load 4.863 us/op
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Load_Advances (Normal) 4.816 us/op
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Load_Advances (Fast) 0.028 us/op
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Render 2.753 us/op
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Get_Glyph 0.463 us/op
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Get_CBox 0.077 us/op
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Get_Char_Index 0.023 us/op
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Iterate CMap 13.898 us/op
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New_Face 12.368 us/op
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Embolden 0.028 us/op
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Get_BBox 0.302 us/op
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After:
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Load 4.617 us/op
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Load_Advances (Normal) 4.645 us/op
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Load_Advances (Fast) 0.027 us/op
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Render 2.789 us/op
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Get_Glyph 0.460 us/op
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Get_CBox 0.077 us/op
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Get_Char_Index 0.024 us/op
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Iterate CMap 13.403 us/op
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New_Face 12.278 us/op
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Embolden 0.028 us/op
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Get_BBox 0.301 us/op
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* builds/unix/ftconfig.in, include/freetype/config/ftconfig.h
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(FT_MulFix_x86_64): New function.
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2013-07-16 David Turner <digit@google.com>
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Speed up ARMv7 support.
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@ -366,6 +366,7 @@ FT_BEGIN_HEADER
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/* These must be defined `static __inline__' with GCC. */
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#if defined( __CC_ARM ) || defined( __ARMCC__ ) /* RVCT */
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#define FT_MULFIX_ASSEMBLER FT_MulFix_arm
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/* documentation is in freetype.h */
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@ -428,7 +429,9 @@ FT_BEGIN_HEADER
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/* ( __thumb2__ || !__thumb__ ) && */
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/* !( __CC_ARM || __ARMCC__ ) */
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#if defined( __i386__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_i386
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/* documentation is in freetype.h */
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@ -497,6 +500,62 @@ FT_BEGIN_HEADER
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#endif /* _MSC_VER */
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#if defined( __GNUC__ ) && defined( __x86_64__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_x86_64
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static __inline__ FT_Int32
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FT_MulFix_x86_64( FT_Int32 a,
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FT_Int32 b )
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{
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/* Temporarily disable the warning that C90 doesn't support */
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/* `long long'. */
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wlong-long"
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#if 1
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/* Technically not an assembly fragment, but GCC does a really good */
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/* job at inlining it and generating good machine code for it. */
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long long ret, tmp;
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ret = (long long)a * b;
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tmp = ret >> 63;
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ret += 0x8000 + tmp;
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return (FT_Int32)( ret >> 16 );
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#else
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/* For some reason, GCC 4.6 on Ubuntu 12.04 generates invalid machine */
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/* code from the lines below. The main issue is that `wide_a' is not */
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/* properly initialized by sign-extending `a'. Instead, the generated */
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/* machine code assumes that the register that contains `a' on input */
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/* can be used directly as a 64-bit value, which is wrong most of the */
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/* time. */
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long long wide_a = (long long)a;
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long long wide_b = (long long)b;
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long long result;
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__asm__ __volatile__ (
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"imul %2, %1\n"
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"mov %1, %0\n"
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"sar $63, %0\n"
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"lea 0x8000(%1, %0), %0\n"
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"sar $16, %0\n"
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: "=&r"(result), "=&r"(wide_a)
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: "r"(wide_b)
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: "cc" );
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return (FT_Int32)result;
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#endif
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#pragma GCC diagnostic pop
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}
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#endif /* __GNUC__ && __x86_64__ */
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#endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
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@ -338,6 +338,7 @@ FT_BEGIN_HEADER
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/* These must be defined `static __inline__' with GCC. */
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#if defined( __CC_ARM ) || defined( __ARMCC__ ) /* RVCT */
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#define FT_MULFIX_ASSEMBLER FT_MulFix_arm
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/* documentation is in freetype.h */
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@ -370,6 +371,7 @@ FT_BEGIN_HEADER
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#if defined( __arm__ ) && \
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( !defined( __thumb__ ) || defined( __thumb2__ ) ) && \
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!( defined( __CC_ARM ) || defined( __ARMCC__ ) )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_arm
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/* documentation is in freetype.h */
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@ -399,7 +401,9 @@ FT_BEGIN_HEADER
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/* ( __thumb2__ || !__thumb__ ) && */
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/* !( __CC_ARM || __ARMCC__ ) */
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#if defined( __i386__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_i386
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/* documentation is in freetype.h */
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@ -468,6 +472,62 @@ FT_BEGIN_HEADER
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#endif /* _MSC_VER */
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#if defined( __GNUC__ ) && defined( __x86_64__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_x86_64
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static __inline__ FT_Int32
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FT_MulFix_x86_64( FT_Int32 a,
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FT_Int32 b )
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{
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/* Temporarily disable the warning that C90 doesn't support */
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/* `long long'. */
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wlong-long"
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#if 1
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/* Technically not an assembly fragment, but GCC does a really good */
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/* job at inlining it and generating good machine code for it. */
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long long ret, tmp;
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ret = (long long)a * b;
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tmp = ret >> 63;
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ret += 0x8000 + tmp;
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return (FT_Int32)( ret >> 16 );
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#else
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/* For some reason, GCC 4.6 on Ubuntu 12.04 generates invalid machine */
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/* code from the lines below. The main issue is that `wide_a' is not */
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/* properly initialized by sign-extending `a'. Instead, the generated */
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/* machine code assumes that the register that contains `a' on input */
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/* can be used directly as a 64-bit value, which is wrong most of the */
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/* time. */
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long long wide_a = (long long)a;
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long long wide_b = (long long)b;
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long long result;
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__asm__ __volatile__ (
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"imul %2, %1\n"
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"mov %1, %0\n"
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"sar $63, %0\n"
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"lea 0x8000(%1, %0), %0\n"
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"sar $16, %0\n"
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: "=&r"(result), "=&r"(wide_a)
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: "r"(wide_b)
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: "cc" );
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return (FT_Int32)result;
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#endif
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#pragma GCC diagnostic pop
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}
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#endif /* __GNUC__ && __x86_64__ */
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#endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
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