777ca513c8
While implementing support for the float128 routines on x86_64, I noticed that __builtin_isinf() was returning true for 128-bit floating point values that are not infinite when compiling with GCC and using the compiler-rt implementation of the soft-float comparison functions. After stepping through the assembly, I discovered that this was caused by GCC assuming a sign-extended 64-bit -1 result, but our implementation returns an enum (which then has zeroes in the upper bits) and therefore causes the comparison with -1 to fail. Fix this by using a CMP_RESULT typedef and add a static_assert that it matches the GCC soft-float comparison return type when compiling with GCC (GCC has a __libgcc_cmp_return__ mode that can be used for this purpose). Also move the 3 copies of the same code to a shared .inc file. Reviewed By: compnerd Differential Revision: https://reviews.llvm.org/D98205
64 lines
2.0 KiB
C
64 lines
2.0 KiB
C
//===-- lib/comparetf2.c - Quad-precision comparisons -------------*- C -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// // This file implements the following soft-float comparison routines:
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//
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// __eqtf2 __getf2 __unordtf2
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// __letf2 __gttf2
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// __lttf2
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// __netf2
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//
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// The semantics of the routines grouped in each column are identical, so there
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// is a single implementation for each, and wrappers to provide the other names.
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//
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// The main routines behave as follows:
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//
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// __letf2(a,b) returns -1 if a < b
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// 0 if a == b
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// 1 if a > b
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// 1 if either a or b is NaN
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//
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// __getf2(a,b) returns -1 if a < b
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// 0 if a == b
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// 1 if a > b
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// -1 if either a or b is NaN
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//
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// __unordtf2(a,b) returns 0 if both a and b are numbers
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// 1 if either a or b is NaN
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//
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// Note that __letf2( ) and __getf2( ) are identical except in their handling of
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// NaN values.
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//
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//===----------------------------------------------------------------------===//
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#define QUAD_PRECISION
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#include "fp_lib.h"
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#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
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#include "fp_compare_impl.inc"
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COMPILER_RT_ABI CMP_RESULT __letf2(fp_t a, fp_t b) { return __leXf2__(a, b); }
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#if defined(__ELF__)
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// Alias for libgcc compatibility
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COMPILER_RT_ALIAS(__letf2, __cmptf2)
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#endif
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COMPILER_RT_ALIAS(__letf2, __eqtf2)
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COMPILER_RT_ALIAS(__letf2, __lttf2)
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COMPILER_RT_ALIAS(__letf2, __netf2)
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COMPILER_RT_ABI CMP_RESULT __getf2(fp_t a, fp_t b) { return __geXf2__(a, b); }
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COMPILER_RT_ALIAS(__getf2, __gttf2)
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COMPILER_RT_ABI CMP_RESULT __unordtf2(fp_t a, fp_t b) {
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return __unordXf2__(a, b);
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}
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#endif
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