Multiply was very wrong for wrapped ranges. This supplies a half-fix that will
generally return Full on all wrapped inputs. "Fixes" PR4545.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75444 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index 8bab537..d7a57bb 100644
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -557,13 +557,13 @@
if (isFullSet() || Other.isFullSet())
return ConstantRange(getBitWidth(), /*isFullSet=*/true);
- ConstantRange this_zext = zeroExtend(getBitWidth() * 2);
- ConstantRange Other_zext = Other.zeroExtend(getBitWidth() * 2);
+ APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
+ APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
+ APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
+ APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
- ConstantRange Result_zext = ConstantRange(
- this_zext.getLower() * Other_zext.getLower(),
- ((this_zext.getUpper()-1) * (Other_zext.getUpper()-1)) + 1);
-
+ ConstantRange Result_zext = ConstantRange(this_min * Other_min,
+ this_max * Other_max + 1);
return Result_zext.truncate(getBitWidth());
}
diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index cd91a9e..2b073d8 100644
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -275,6 +275,11 @@
EXPECT_TRUE(Some.multiply(Some).isFullSet());
EXPECT_EQ(Some.multiply(Wrap), Full);
EXPECT_EQ(Wrap.multiply(Wrap), Full);
+
+ // http://llvm.org/PR4545
+ EXPECT_EQ(ConstantRange(APInt(4, 1), APInt(4, 6)).multiply(
+ ConstantRange(APInt(4, 6), APInt(4, 2))),
+ ConstantRange(4, /*isFullSet=*/true));
}
TEST_F(ConstantRangeTest, UMax) {