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Add __divmodti4 to match libgcc.
gcc has used this on x86-64 since at least version 7. Reviewed By: MaskRay Differential Revision: https://reviews.llvm.org/D80506
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‎compiler-rt/lib/builtins/CMakeLists.txt

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@@ -71,6 +71,7 @@ set(GENERIC_SOURCES
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divdi3.c
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divmoddi4.c
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divmodsi4.c
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divmodti4.c
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divsc3.c
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divsf3.c
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divsi3.c

‎compiler-rt/lib/builtins/README.txt

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@@ -87,6 +87,8 @@ du_int __udivmoddi4(du_int a, du_int b, du_int* rem); // a / b, *rem = a % b u
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tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b unsigned
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su_int __udivmodsi4(su_int a, su_int b, su_int* rem); // a / b, *rem = a % b unsigned
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si_int __divmodsi4(si_int a, si_int b, si_int* rem); // a / b, *rem = a % b signed
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di_int __divmoddi4(di_int a, di_int b, di_int* rem); // a / b, *rem = a % b signed
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ti_int __divmodti4(ti_int a, ti_int b, ti_int* rem); // a / b, *rem = a % b signed
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‎compiler-rt/lib/builtins/divmodti4.c

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//===-- divmodti4.c - Implement __divmodti4 -------------------------------===//
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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 __divmodti4 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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#ifdef CRT_HAS_128BIT
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// Returns: a / b, *rem = a % b
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COMPILER_RT_ABI ti_int __divmodti4(ti_int a, ti_int b, ti_int *rem) {
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const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
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ti_int s_a = a >> bits_in_tword_m1; // s_a = a < 0 ? -1 : 0
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ti_int s_b = b >> bits_in_tword_m1; // s_b = b < 0 ? -1 : 0
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a = (a ^ s_a) - s_a; // negate if s_a == -1
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b = (b ^ s_b) - s_b; // negate if s_b == -1
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s_b ^= s_a; // sign of quotient
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tu_int r;
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ti_int q = (__udivmodti4(a, b, &r) ^ s_b) - s_b; // negate if s_b == -1
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*rem = (r ^ s_a) - s_a; // negate if s_a == -1
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return q;
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}
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#endif // CRT_HAS_128BIT

‎compiler-rt/test/builtins/Unit/divmodti4_test.c

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// RUN: %clang_builtins %s %librt -o %t && %run %t
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// REQUIRES: librt_has_divmodti4
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// REQUIRES: int128
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//===-- divmodti4_test.c - Test __divmodti4 -------------------------------===//
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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 tests __divmodti4 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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#include <stdio.h>
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#ifdef CRT_HAS_128BIT
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// Effects: if rem != 0, *rem = a % b
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// Returns: a / b
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COMPILER_RT_ABI ti_int __divmodti4(ti_int a, ti_int b, ti_int* rem);
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int test__divmodti4(ti_int a, ti_int b, ti_int expected_q, ti_int expected_r) {
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ti_int r;
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ti_int q = __divmodti4(a, b, &r);
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if (q != expected_q || r != expected_r)
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{
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utwords at;
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at.all = a;
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utwords bt;
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bt.all = b;
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utwords expected_qt;
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expected_qt.all = expected_q;
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utwords expected_rt;
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expected_rt.all = expected_r;
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utwords qt;
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qt.all = q;
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utwords rt;
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rt.all = r;
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printf("error in __divmodti4: 0x%.16llX%.16llX / 0x%.16llX%.16llX = "
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"0x%.16llX%.16llX, R = 0x%.16llX%.16llX, expected 0x%.16llX%.16llX, "
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"0x%.16llX%.16llX\n",
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at.s.high, at.s.low, bt.s.high, bt.s.low, qt.s.high, qt.s.low,
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rt.s.high, rt.s.low, expected_qt.s.high, expected_qt.s.low,
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expected_rt.s.high, expected_rt.s.low);
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}
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return !(q == expected_q && r == expected_r);
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}
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char assumption_1[sizeof(ti_int) == 2*sizeof(di_int)] = {0};
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tu_int tests[][4] =
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{
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{ (ti_int) 0, (ti_int) 1, (ti_int) 0, (ti_int) 0 },
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{ (ti_int) 0, (ti_int)-1, (ti_int) 0, (ti_int) 0 },
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{ (ti_int) 2, (ti_int) 1, (ti_int) 2, (ti_int) 0 },
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{ (ti_int) 2, (ti_int)-1, (ti_int)-2, (ti_int) 0 },
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{ (ti_int)-2, (ti_int) 1, (ti_int)-2, (ti_int) 0 },
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{ (ti_int)-2, (ti_int)-1, (ti_int) 2, (ti_int) 0 },
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{ (ti_int) 5, (ti_int) 3, (ti_int) 1, (ti_int) 2 },
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{ (ti_int) 5, (ti_int)-3, (ti_int)-1, (ti_int) 2 },
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{ (ti_int)-5, (ti_int) 3, (ti_int)-1, (ti_int)-2 },
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{ (ti_int)-5, (ti_int)-3, (ti_int) 1, (ti_int)-2 },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int) 1, (ti_int)0x8000000000000000LL << 64 | 0, (ti_int)0x0LL },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int)-1, (ti_int)0x8000000000000000LL << 64 | 0, (ti_int)0x0LL },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int)-2, (ti_int)0x4000000000000000LL << 64 | 0, (ti_int)0x0LL },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int) 2, (ti_int)0xC000000000000000LL << 64 | 0, (ti_int)0x0LL },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int)-3, (ti_int)0x2AAAAAAAAAAAAAAALL << 64 | 0xAAAAAAAAAAAAAAAALL, (ti_int)-2 },
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{ (ti_int)0x8000000000000000LL << 64 | 0, (ti_int) 3, (ti_int)0xD555555555555555LL << 64 | 0x5555555555555556LL, (ti_int)-2 },
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};
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#endif
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int main()
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{
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#ifdef CRT_HAS_128BIT
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const unsigned N = sizeof(tests) / sizeof(tests[0]);
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unsigned i;
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for (i = 0; i < N; ++i)
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if (test__divmodti4(tests[i][0], tests[i][1], tests[i][2], tests[i][3]))
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return 1;
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#else
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printf("skipped\n");
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#endif
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return 0;
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}

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