[llvm] 6d30223 - [ADT][APInt] add sfloordiv_ov APInt's member function (#84720)
via llvm-commits
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Fri Mar 15 04:09:49 PDT 2024
Author: long.chen
Date: 2024-03-15T19:09:46+08:00
New Revision: 6d30223f7c66ca07ea7ff40ffba426f2dc789e74
URL: https://github.com/llvm/llvm-project/commit/6d30223f7c66ca07ea7ff40ffba426f2dc789e74
DIFF: https://github.com/llvm/llvm-project/commit/6d30223f7c66ca07ea7ff40ffba426f2dc789e74.diff
LOG: [ADT][APInt] add sfloordiv_ov APInt's member function (#84720)
for mlir fold to avoid too many overflow state check
Added:
Modified:
llvm/include/llvm/ADT/APInt.h
llvm/lib/Support/APInt.cpp
llvm/unittests/ADT/APIntTest.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/ADT/APInt.h b/llvm/include/llvm/ADT/APInt.h
index b10e2107b794a3..1abea9eb24a3c4 100644
--- a/llvm/include/llvm/ADT/APInt.h
+++ b/llvm/include/llvm/ADT/APInt.h
@@ -997,6 +997,12 @@ class [[nodiscard]] APInt {
APInt ushl_ov(const APInt &Amt, bool &Overflow) const;
APInt ushl_ov(unsigned Amt, bool &Overflow) const;
+ /// Signed integer floor division operation.
+ ///
+ /// Rounds towards negative infinity, i.e. 5 / -2 = -3. Iff minimum value
+ /// divided by -1 set Overflow to true.
+ APInt sfloordiv_ov(const APInt &RHS, bool &Overflow) const;
+
// Operations that saturate
APInt sadd_sat(const APInt &RHS) const;
APInt uadd_sat(const APInt &RHS) const;
diff --git a/llvm/lib/Support/APInt.cpp b/llvm/lib/Support/APInt.cpp
index c530f7b78e186f..7a383c3236d9b1 100644
--- a/llvm/lib/Support/APInt.cpp
+++ b/llvm/lib/Support/APInt.cpp
@@ -2022,6 +2022,13 @@ APInt APInt::ushl_ov(unsigned ShAmt, bool &Overflow) const {
return *this << ShAmt;
}
+APInt APInt::sfloordiv_ov(const APInt &RHS, bool &Overflow) const {
+ APInt quotient = sdiv_ov(RHS, Overflow);
+ if ((quotient * RHS != *this) && (isNegative() != RHS.isNegative()))
+ return quotient - 1;
+ return quotient;
+}
+
APInt APInt::sadd_sat(const APInt &RHS) const {
bool Overflow;
APInt Res = sadd_ov(RHS, Overflow);
diff --git a/llvm/unittests/ADT/APIntTest.cpp b/llvm/unittests/ADT/APIntTest.cpp
index 400313a6234677..6aec1049584bbe 100644
--- a/llvm/unittests/ADT/APIntTest.cpp
+++ b/llvm/unittests/ADT/APIntTest.cpp
@@ -15,6 +15,7 @@
#include "gtest/gtest.h"
#include <array>
#include <climits>
+#include <limits>
#include <optional>
using namespace llvm;
@@ -3048,6 +3049,69 @@ TEST(APIntTest, smul_ov) {
}
}
+TEST(APIntTest, sfloordiv_ov) {
+ // int16 test overflow
+ {
+ using IntTy = int16_t;
+ APInt divisor(8 * sizeof(IntTy), std::numeric_limits<IntTy>::lowest(),
+ true);
+ APInt dividend(8 * sizeof(IntTy), IntTy(-1), true);
+ bool Overflow = false;
+ (void)divisor.sfloordiv_ov(dividend, Overflow);
+ EXPECT_TRUE(Overflow);
+ }
+ // int32 test overflow
+ {
+ using IntTy = int32_t;
+ APInt divisor(8 * sizeof(IntTy), std::numeric_limits<IntTy>::lowest(),
+ true);
+ APInt dividend(8 * sizeof(IntTy), IntTy(-1), true);
+ bool Overflow = false;
+ (void)divisor.sfloordiv_ov(dividend, Overflow);
+ EXPECT_TRUE(Overflow);
+ }
+ // int64 test overflow
+ {
+ using IntTy = int64_t;
+ APInt divisor(8 * sizeof(IntTy), std::numeric_limits<IntTy>::lowest(),
+ true);
+ APInt dividend(8 * sizeof(IntTy), IntTy(-1), true);
+ bool Overflow = false;
+ (void)divisor.sfloordiv_ov(dividend, Overflow);
+ EXPECT_TRUE(Overflow);
+ }
+ // test all of int8
+ {
+ bool Overflow = false;
+ for (int i = -128; i < 128; ++i) {
+ for (int j = -128; j < 128; ++j) {
+ if (j == 0)
+ continue;
+
+ int8_t a = static_cast<int8_t>(i);
+ int8_t b = static_cast<int8_t>(j);
+
+ APInt divisor(8, a, true);
+ APInt dividend(8, b, true);
+ APInt quotient = divisor.sfloordiv_ov(dividend, Overflow);
+
+ if (i == -128 && j == -1) {
+ EXPECT_TRUE(Overflow);
+ continue;
+ }
+
+ if (((i >= 0 && j > 0) || (i <= 0 && j < 0)) ||
+ (i % j == 0)) // if quotient >= 0 and remain == 0 floordiv
+ // equivalent to div
+ EXPECT_EQ(quotient.getSExtValue(), a / b);
+ else
+ EXPECT_EQ(quotient.getSExtValue(), a / b - 1);
+ EXPECT_FALSE(Overflow);
+ }
+ }
+ }
+}
+
TEST(APIntTest, SolveQuadraticEquationWrap) {
// Verify that "Solution" is the first non-negative integer that solves
// Ax^2 + Bx + C = "0 or overflow", i.e. that it is a correct solution
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