[ConstantFPRange] Add support for fneg/fabs #162690
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dtcxzyw
requested review from
andykaylor,
arsenm,
jayfoad,
jcranmer-intel and
nikic
|
@llvm/pr-subscribers-llvm-ir Author: Yingwei Zheng (dtcxzyw) ChangesThis patch adds support for fneg/fabs operations. For other bit manipulation operations (select/copysign), we don't need new APIs. Full diff: https://github.com/llvm/llvm-project/pull/162690.diff 3 Files Affected:
diff --git a/llvm/include/llvm/IR/ConstantFPRange.h b/llvm/include/llvm/IR/ConstantFPRange.h
index 930c6f98c033f..4a54caa87eaca 100644
--- a/llvm/include/llvm/IR/ConstantFPRange.h
+++ b/llvm/include/llvm/IR/ConstantFPRange.h
@@ -200,6 +200,12 @@ class [[nodiscard]] ConstantFPRange {
/// with another range. The resultant range is guaranteed to include the
/// elements of both sets, but may contain more.
LLVM_ABI ConstantFPRange unionWith(const ConstantFPRange &CR) const;
+
+ /// Calculate absolute value range.
+ LLVM_ABI ConstantFPRange abs() const;
+
+ /// Calculate range of negated values.
+ LLVM_ABI ConstantFPRange negate() const;
};
inline raw_ostream &operator<<(raw_ostream &OS, const ConstantFPRange &CR) {
diff --git a/llvm/lib/IR/ConstantFPRange.cpp b/llvm/lib/IR/ConstantFPRange.cpp
index 7509188128524..969af9798bf06 100644
--- a/llvm/lib/IR/ConstantFPRange.cpp
+++ b/llvm/lib/IR/ConstantFPRange.cpp
@@ -391,3 +391,23 @@ ConstantFPRange ConstantFPRange::unionWith(const ConstantFPRange &CR) const {
return ConstantFPRange(minnum(Lower, CR.Lower), maxnum(Upper, CR.Upper),
MayBeQNaN | CR.MayBeQNaN, MayBeSNaN | CR.MayBeSNaN);
}
+
+ConstantFPRange ConstantFPRange::abs() const {
+ if (isEmptySet())
+ return *this;
+ // Check if the range is all non-negative or all non-positive.
+ if (Lower.isNegative() == Upper.isNegative()) {
+ if (Lower.isNegative())
+ return negate();
+ return *this;
+ }
+ // The range contains both positive and negative values.
+ APFloat NewLower = APFloat::getZero(getSemantics());
+ APFloat NewUpper = maxnum(-Lower, Upper);
+ return ConstantFPRange(std::move(NewLower), std::move(NewUpper), MayBeQNaN,
+ MayBeSNaN);
+}
+
+ConstantFPRange ConstantFPRange::negate() const {
+ return ConstantFPRange(-Upper, -Lower, MayBeQNaN, MayBeSNaN);
+}
diff --git a/llvm/unittests/IR/ConstantFPRangeTest.cpp b/llvm/unittests/IR/ConstantFPRangeTest.cpp
index 255f62d77b748..1384b68707577 100644
--- a/llvm/unittests/IR/ConstantFPRangeTest.cpp
+++ b/llvm/unittests/IR/ConstantFPRangeTest.cpp
@@ -767,4 +767,37 @@ TEST_F(ConstantFPRangeTest, makeExactFCmpRegion) {
}
}
+TEST_F(ConstantFPRangeTest, abs) {
+ EXPECT_EQ(Full.abs(),
+ ConstantFPRange(APFloat::getZero(Sem, /*Negative=*/false),
+ APFloat::getInf(Sem, /*Negative=*/false),
+ /*MayBeQNaN=*/true,
+ /*MayBeSNaN=*/true));
+ EXPECT_EQ(Empty.abs(), Empty);
+ EXPECT_EQ(Zero.abs(), PosZero);
+ EXPECT_EQ(PosInf.abs(), PosInf);
+ EXPECT_EQ(NegInf.abs(), PosInf);
+ EXPECT_EQ(Some.abs(), SomePos);
+ EXPECT_EQ(SomeNeg.abs(), SomePos);
+ EXPECT_EQ(ConstantFPRange::getNonNaN(APFloat(-2.0), APFloat(3.0)).abs(),
+ ConstantFPRange::getNonNaN(APFloat(0.0), APFloat(3.0)));
+ EXPECT_EQ(ConstantFPRange::getNonNaN(APFloat(-3.0), APFloat(2.0)).abs(),
+ ConstantFPRange::getNonNaN(APFloat(0.0), APFloat(3.0)));
+}
+
+TEST_F(ConstantFPRangeTest, negate) {
+ EXPECT_EQ(Full.negate(), Full);
+ EXPECT_EQ(Empty.negate(), Empty);
+ EXPECT_EQ(Zero.negate(), Zero);
+ EXPECT_EQ(PosInf.negate(), NegInf);
+ EXPECT_EQ(NegInf.negate(), PosInf);
+ EXPECT_EQ(Some.negate(), Some);
+ EXPECT_EQ(SomePos.negate(), SomeNeg);
+ EXPECT_EQ(SomeNeg.negate(), SomePos);
+ EXPECT_EQ(ConstantFPRange::getNonNaN(APFloat(-2.0), APFloat(3.0)).negate(),
+ ConstantFPRange::getNonNaN(APFloat(-3.0), APFloat(2.0)));
+ EXPECT_EQ(ConstantFPRange::getNonNaN(APFloat(-3.0), APFloat(2.0)).negate(),
+ ConstantFPRange::getNonNaN(APFloat(-2.0), APFloat(3.0)));
+}
+
} // anonymous namespace
|
arsenm
approved these changes
Oct 9, 2025
nikic
approved these changes
Oct 9, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/138/builds/20228 Here is the relevant piece of the build log for the reference |
jayfoad
reviewed
Oct 10, 2025
Comment on lines
+399
to
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| if (Lower.isNegative() == Upper.isNegative()) { | ||
| if (Lower.isNegative()) | ||
| return negate(); | ||
| return *this; | ||
| } |
There was a problem hiding this comment.
Simpler:
Suggested change
| if (Lower.isNegative() == Upper.isNegative()) { | |
| if (Lower.isNegative()) | |
| return negate(); | |
| return *this; | |
| } | |
| if (!Lower.isNegative()) | |
| return *this; | |
| if (Upper.isNegative()) | |
| return negate(); |
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This patch adds support for fneg/fabs operations. For other bit manipulation operations (select/copysign), we don't need new APIs.