Fix bitcasting E8M0 APFloat to APInt #113298
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@llvm/pr-subscribers-llvm-adt Author: Sergey Kozub (sergey-kozub) ChangesFull diff: https://github.com/llvm/llvm-project/pull/113298.diff 2 Files Affected:
diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index a33b6c4a6ddc63..157a6a3c561884 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/lib/Support/APFloat.cpp
@@ -3663,7 +3663,7 @@ APInt IEEEFloat::convertIEEEFloatToAPInt() const {
std::array<uint64_t, (S.sizeInBits + 63) / 64> words;
auto words_iter =
std::copy_n(mysignificand.begin(), mysignificand.size(), words.begin());
- if constexpr (significand_mask != 0) {
+ if constexpr (significand_mask != 0 || trailing_significand_bits == 0) {
// Clear the integer bit.
words[mysignificand.size() - 1] &= significand_mask;
}
diff --git a/llvm/unittests/ADT/APFloatTest.cpp b/llvm/unittests/ADT/APFloatTest.cpp
index 665cff9c424594..a4d72f2dd369ac 100644
--- a/llvm/unittests/ADT/APFloatTest.cpp
+++ b/llvm/unittests/ADT/APFloatTest.cpp
@@ -7614,6 +7614,15 @@ TEST(APFloatTest, ConvertDoubleToE8M0FNU) {
EXPECT_EQ(status, APFloat::opUnderflow | APFloat::opInexact);
}
+TEST(APFloatTest, Float8E8M0FNUBitcastToAPInt) {
+ // Regression test for verifying the low bit of the exponent when bitcasting
+ // to integer (zero mantissa).
+ APFloat f0(APFloat::Float8E8M0FNU(), "0.5");
+ APFloat f1(APFloat::Float8E8M0FNU(), "1.0");
+ EXPECT_EQ(f0.bitcastToAPInt(), 126) << f0;
+ EXPECT_EQ(f1.bitcastToAPInt(), 127) << f1;
+}
+
TEST(APFloatTest, Float6E3M2FNFromString) {
// Exactly representable
EXPECT_EQ(28, APFloat(APFloat::Float6E3M2FN(), "28").convertToDouble());
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@llvm/pr-subscribers-llvm-support Author: Sergey Kozub (sergey-kozub) ChangesFull diff: https://github.com/llvm/llvm-project/pull/113298.diff 2 Files Affected:
diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index a33b6c4a6ddc63..157a6a3c561884 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/lib/Support/APFloat.cpp
@@ -3663,7 +3663,7 @@ APInt IEEEFloat::convertIEEEFloatToAPInt() const {
std::array<uint64_t, (S.sizeInBits + 63) / 64> words;
auto words_iter =
std::copy_n(mysignificand.begin(), mysignificand.size(), words.begin());
- if constexpr (significand_mask != 0) {
+ if constexpr (significand_mask != 0 || trailing_significand_bits == 0) {
// Clear the integer bit.
words[mysignificand.size() - 1] &= significand_mask;
}
diff --git a/llvm/unittests/ADT/APFloatTest.cpp b/llvm/unittests/ADT/APFloatTest.cpp
index 665cff9c424594..a4d72f2dd369ac 100644
--- a/llvm/unittests/ADT/APFloatTest.cpp
+++ b/llvm/unittests/ADT/APFloatTest.cpp
@@ -7614,6 +7614,15 @@ TEST(APFloatTest, ConvertDoubleToE8M0FNU) {
EXPECT_EQ(status, APFloat::opUnderflow | APFloat::opInexact);
}
+TEST(APFloatTest, Float8E8M0FNUBitcastToAPInt) {
+ // Regression test for verifying the low bit of the exponent when bitcasting
+ // to integer (zero mantissa).
+ APFloat f0(APFloat::Float8E8M0FNU(), "0.5");
+ APFloat f1(APFloat::Float8E8M0FNU(), "1.0");
+ EXPECT_EQ(f0.bitcastToAPInt(), 126) << f0;
+ EXPECT_EQ(f1.bitcastToAPInt(), 127) << f1;
+}
+
TEST(APFloatTest, Float6E3M2FNFromString) {
// Exactly representable
EXPECT_EQ(28, APFloat(APFloat::Float6E3M2FN(), "28").convertToDouble());
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durga4github
approved these changes
Oct 22, 2024
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/123/builds/7956 Here is the relevant piece of the build log for the reference |
EricWF
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Oct 22, 2024
Fixes a bug in APFloat handling of E8M0 type (zero mantissa). Related PRs: - llvm#107127 - llvm#111028
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Fixes a bug in APFloat handling of E8M0 type (zero mantissa).
Related PRs: