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Date:      Sat, 23 May 2020 11:06:46 +0000
From:      bugzilla-noreply@freebsd.org
To:        toolchain@FreeBSD.org
Subject:   [Bug 244169] [clang] __builtin_mul_overflow() with 64-bit values requires __muloti4 which is missing on 32-bit architectures
Message-ID:  <bug-244169-29464-ehG6wEyErG@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-244169-29464@https.bugs.freebsd.org/bugzilla/>
References:  <bug-244169-29464@https.bugs.freebsd.org/bugzilla/>

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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D244169

Dimitry Andric <dim@FreeBSD.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dim@FreeBSD.org

--- Comment #1 from Dimitry Andric <dim@FreeBSD.org> ---
We do compile contrib/llvm-project/compiler-rt/lib/builtins/muloti4.c as pa=
rt
of libcompiler_rt, but the file starts with:

#include "int_lib.h"

#ifdef CRT_HAS_128BIT

// Returns: a * b

// Effects: sets *overflow to 1  if a * b overflows

COMPILER_RT_ABI ti_int __muloti4(ti_int a, ti_int b, int *overflow) {

Obviously, CRT_HAS_128BIT is false on 32-bit platforms; it is defined in
int_lib.h as:

#if defined(__LP64__) || defined(__wasm__) || defined(__mips64) ||=20=20=20=
=20=20=20=20=20=20=20=20=20
\
    defined(__riscv) || defined(_WIN64)
#define CRT_HAS_128BIT
#endif

So I'm not really sure what we can do about this...

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