[PATCH] D69398: [APInt} Add saturating left-shift ops
Roman Lebedev via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 24 10:47:50 PDT 2019
lebedev.ri created this revision.
lebedev.ri added reviewers: spatel, nikic.
lebedev.ri added a project: LLVM.
Herald added subscribers: dexonsmith, hiraditya.
lebedev.ri added a parent revision: D69397: [APInt} Add saturating multiply ops.
There are `*_ov()` functions already, so at least for consistency it may be good to also have saturating variants.
These may or may not be needed for `ConstantRange`'s `shlWithNoWrap()`
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D69398
Files:
llvm/include/llvm/ADT/APInt.h
llvm/lib/Support/APInt.cpp
llvm/unittests/ADT/APIntTest.cpp
Index: llvm/unittests/ADT/APIntTest.cpp
===================================================================
--- llvm/unittests/ADT/APIntTest.cpp
+++ llvm/unittests/ADT/APIntTest.cpp
@@ -1215,6 +1215,23 @@
EXPECT_EQ(APInt(8, -128), APInt(8, 25).smul_sat(APInt(8, -6)));
EXPECT_EQ(APInt(8, 127), APInt(8, -25).smul_sat(APInt(8, -6)));
EXPECT_EQ(APInt(8, 127), APInt(8, 25).smul_sat(APInt(8, 6)));
+
+ EXPECT_EQ(APInt(8, 128), APInt(8, 4).ushl_sat(APInt(8, 5)));
+ EXPECT_EQ(APInt(8, 255), APInt(8, 4).ushl_sat(APInt(8, 6)));
+ EXPECT_EQ(APInt(8, 128), APInt(8, 1).ushl_sat(APInt(8, 7)));
+ EXPECT_EQ(APInt(8, 255), APInt(8, 1).ushl_sat(APInt(8, 8)));
+ EXPECT_EQ(APInt(8, 255), APInt(8, -128).ushl_sat(APInt(8, 2)));
+ EXPECT_EQ(APInt(8, 255), APInt(8, 64).ushl_sat(APInt(8, 2)));
+ EXPECT_EQ(APInt(8, 255), APInt(8, 64).ushl_sat(APInt(8, -2)));
+
+ EXPECT_EQ(APInt(8, 64), APInt(8, 4).sshl_sat(APInt(8, 4)));
+ EXPECT_EQ(APInt(8, 127), APInt(8, 4).sshl_sat(APInt(8, 5)));
+ EXPECT_EQ(APInt(8, 127), APInt(8, 1).sshl_sat(APInt(8, 8)));
+ EXPECT_EQ(APInt(8, -64), APInt(8, -4).sshl_sat(APInt(8, 4)));
+ EXPECT_EQ(APInt(8, -128), APInt(8, -4).sshl_sat(APInt(8, 5)));
+ EXPECT_EQ(APInt(8, -128), APInt(8, -4).sshl_sat(APInt(8, 6)));
+ EXPECT_EQ(APInt(8, -128), APInt(8, -1).sshl_sat(APInt(8, 7)));
+ EXPECT_EQ(APInt(8, -128), APInt(8, -1).sshl_sat(APInt(8, 8)));
}
TEST(APIntTest, FromArray) {
Index: llvm/lib/Support/APInt.cpp
===================================================================
--- llvm/lib/Support/APInt.cpp
+++ llvm/lib/Support/APInt.cpp
@@ -2070,6 +2070,25 @@
return APInt::getMaxValue(BitWidth);
}
+APInt APInt::sshl_sat(const APInt &RHS) const {
+ bool Overflow;
+ APInt Res = sshl_ov(RHS, Overflow);
+ if (!Overflow)
+ return Res;
+
+ return isNegative() ? APInt::getSignedMinValue(BitWidth)
+ : APInt::getSignedMaxValue(BitWidth);
+}
+
+APInt APInt::ushl_sat(const APInt &RHS) const {
+ bool Overflow;
+ APInt Res = ushl_ov(RHS, Overflow);
+ if (!Overflow)
+ return Res;
+
+ return APInt::getMaxValue(BitWidth);
+}
+
void APInt::fromString(unsigned numbits, StringRef str, uint8_t radix) {
// Check our assumptions here
assert(!str.empty() && "Invalid string length");
Index: llvm/include/llvm/ADT/APInt.h
===================================================================
--- llvm/include/llvm/ADT/APInt.h
+++ llvm/include/llvm/ADT/APInt.h
@@ -1111,6 +1111,8 @@
APInt usub_sat(const APInt &RHS) const;
APInt smul_sat(const APInt &RHS) const;
APInt umul_sat(const APInt &RHS) const;
+ APInt sshl_sat(const APInt &RHS) const;
+ APInt ushl_sat(const APInt &RHS) const;
/// Array-indexing support.
///
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