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[builtins] Support building the 128-bit float functions on i386 #122658

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[builtins] Support building the 128-bit float functions on i386 #122658

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3 changes: 2 additions & 1 deletion compiler-rt/lib/builtins/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -356,6 +356,7 @@ if (NOT MSVC)
set(i386_SOURCES
${GENERIC_SOURCES}
${x86_ARCH_SOURCES}
${GENERIC_TF_SOURCES}
i386/ashldi3.S
i386/ashrdi3.S
i386/divdi3.S
Expand Down Expand Up @@ -906,7 +907,7 @@ else ()

# For RISCV32, we must force enable int128 for compiling long
# double routines.
if(COMPILER_RT_ENABLE_SOFTWARE_INT128 OR "${arch}" STREQUAL "riscv32")
if(COMPILER_RT_ENABLE_SOFTWARE_INT128 OR "${arch}" STREQUAL "riscv32" OR "${arch}" STREQUAL "i386")
list(APPEND BUILTIN_CFLAGS_${arch} -fforce-enable-int128)
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Do we support other compilers? If so enabling this unconditionally for i386 might break them?

endif()

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3 changes: 2 additions & 1 deletion compiler-rt/lib/builtins/extendxftf2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,8 @@
#define QUAD_PRECISION
#include "fp_lib.h"

#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && defined(__x86_64__)
#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && \
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This change is concerning. Not all 32-bit environments support FP80. Concretely, Windows, FreeBSD, and Darwin definitely do support FP80 even though the hardware does. This can make it easy to get ABI breakages.

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how about only enable for linux

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This should actually be checking HAS_80_BIT_LONG_DOUBLE, which is set correctly depending on environments that support it:

llvm-project/compiler-rt/lib/builtins/int_types.h

Line 158 in 4a4a8a1

#if (defined(__i386__) || defined(__x86_64__)) && \

Suggested change
#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && \
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

(defined(__x86_64__) || defined(__i386__))
#define SRC_80
#define DST_QUAD
#include "fp_extend_impl.inc"
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3 changes: 2 additions & 1 deletion compiler-rt/lib/builtins/trunctfxf2.c
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Expand Up @@ -12,7 +12,8 @@
#define QUAD_PRECISION
#include "fp_lib.h"

#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && defined(__x86_64__)
#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && \
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Likewise

(defined(__x86_64__) || defined(__i386__))
Comment on lines +15 to +16
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Suggested change
#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && \
(defined(__x86_64__) || defined(__i386__))
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

As above


#define SRC_QUAD
#define DST_80
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6 changes: 3 additions & 3 deletions compiler-rt/test/builtins/Unit/extendxftf2_test.c
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@@ -1,10 +1,10 @@
// RUN: %clang_builtins %s %librt -o %t && %run %t
// RUN: %clang_builtins %s %librt -fforce-enable-int128 -o %t && %run %t
// REQUIRES: librt_has_extendxftf2

#include "int_lib.h"
#include <stdio.h>

#if __LDBL_MANT_DIG__ == 64 && defined(__x86_64__) && \
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))

Comment on lines +7 to 8
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Suggested change
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

Since we include int_lib.h should be possible to simplify this

#include "fp_test.h"
Expand All @@ -28,7 +28,7 @@ char assumption_1[sizeof(long double) * CHAR_BIT == 128] = {0};
#endif

int main() {
#if __LDBL_MANT_DIG__ == 64 && defined(__x86_64__) && \
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
// qNaN
Comment on lines +31 to 32
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Suggested change
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

Since we include int_lib.h should be possible to simplify this

if (test__extendxftf2(makeQNaN80(), UINT64_C(0x7fff800000000000),
Expand Down
6 changes: 3 additions & 3 deletions compiler-rt/test/builtins/Unit/trunctfxf2_test.c
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@@ -1,10 +1,10 @@
// RUN: %clang_builtins %s %librt -o %t && %run %t
// RUN: %clang_builtins %s %librt -fforce-enable-int128 -o %t && %run %t
// REQUIRES: librt_has_trunctfxf2
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Will adding this flag unconditionally break other/older compilers? Maybe this needs to be a lit substitution?


#include "int_lib.h"
#include <stdio.h>

#if __LDBL_MANT_DIG__ == 64 && defined(__x86_64__) && \
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))

Comment on lines +7 to 8
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Suggested change
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

Since we include int_lib.h should be possible to simplify this

#include "fp_test.h"
Expand All @@ -28,7 +28,7 @@ char assumption_1[sizeof(long double) * CHAR_BIT == 128] = {0};
#endif

int main() {
#if __LDBL_MANT_DIG__ == 64 && defined(__x86_64__) && \
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
// qNaN
Comment on lines +31 to 32
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Suggested change
#if __LDBL_MANT_DIG__ == 64 && (defined(__x86_64__) || defined(__i386__)) && \
(defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__))
#if defined(CRT_HAS_TF_MODE) && HAS_80_BIT_LONG_DOUBLE

Since we include int_lib.h should be possible to simplify this

if (test__trunctfxf2(makeQNaN128(), UINT64_C(0x7FFF),
Expand Down
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