[ConstantRange] Shl considers full-set shifting to last bit position.
if we do SHL of two 16-bit ranges like [0, 30000) with [1,2) we get
"full-set" instead of what I would have expected [0, 60000) which is
still in the 16-bit unsigned range.
This patch changes the SHL algorithm to allow getting a usable range
even in this case.
Differential Revision: https://reviews.llvm.org/D57983
llvm-svn: 357854
diff --git a/llvm/unittests/IR/ConstantRangeTest.cpp b/llvm/unittests/IR/ConstantRangeTest.cpp
index c9273bc..db298bc 100644
--- a/llvm/unittests/IR/ConstantRangeTest.cpp
+++ b/llvm/unittests/IR/ConstantRangeTest.cpp
@@ -704,6 +704,8 @@
}
TEST_F(ConstantRangeTest, Shl) {
+ ConstantRange Some2(APInt(16, 0xfff), APInt(16, 0x8000));
+ ConstantRange WrapNullMax(APInt(16, 0x1), APInt(16, 0x0));
EXPECT_EQ(Full.shl(Full), Full);
EXPECT_EQ(Full.shl(Empty), Empty);
EXPECT_EQ(Full.shl(One), Full); // TODO: [0, (-1 << 0xa) + 1)
@@ -720,6 +722,10 @@
EXPECT_EQ(Some.shl(Some), Full); // TODO: [0xa << 0xa, 0xfc01)
EXPECT_EQ(Some.shl(Wrap), Full); // TODO: [0xa, 0x7ff << 0x5 + 1)
EXPECT_EQ(Wrap.shl(Wrap), Full);
+ EXPECT_EQ(
+ Some2.shl(ConstantRange(APInt(16, 0x1))),
+ ConstantRange(APInt(16, 0xfff << 0x1), APInt(16, 0x7fff << 0x1) + 1));
+ EXPECT_EQ(One.shl(WrapNullMax), Full);
}
TEST_F(ConstantRangeTest, Lshr) {