fb463778a7
When compiling the builtins with the undefined behavior sanitizer and running testcases you end up with the following warning: UBSan: negdi2.c:20:10: negation of -9223372036854775808 cannot be represented in type 'di_int' (aka 'long long'); cast to an unsigned type to negate this value to itself This can be avoided by doing negation in a matching unsigned variant of the type. The same kind of pattern is found in negti2.c This was found in an out of tree target. Reviewed By: MaskRay Differential Revision: https://reviews.llvm.org/D158818
22 lines
727 B
C
22 lines
727 B
C
//===-- negdi2.c - Implement __negdi2 -------------------------------------===//
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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 __negdi2 for the compiler_rt library.
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//
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//===----------------------------------------------------------------------===//
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#include "int_lib.h"
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// Returns: -a
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COMPILER_RT_ABI di_int __negdi2(di_int a) {
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// Note: this routine is here for API compatibility; any sane compiler
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// should expand it inline.
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return -(du_int)a;
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}
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