Fix handling of max and full set.

A full set is a constant range that represents any number. If you take the
umax of that and [5, 10) you end up with [5, INT_MAX] because the values less
than 5 would be umax's against a value which is at least 5.

llvm-svn: 75372

2 files changed, 8 insertions, 11 deletions

diff --git a/llvm/lib/Support/ConstantRange.cpp b/llvm/lib/Support/ConstantRange.cpp
index f5b408f8a55..ad301c3e18a 100644
--- a/llvm/lib/Support/ConstantRange.cpp
+++ b/llvm/lib/Support/ConstantRange.cpp
@@ -561,8 +561,6 @@ ConstantRange::smax(const ConstantRange &Other) const {
   //                    smax(X_smax, Y_smax))
   if (isEmptySet() || Other.isEmptySet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
-  if (isFullSet() || Other.isFullSet())
-    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
   APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
   APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
   if (NewU == NewL)
@@ -576,8 +574,6 @@ ConstantRange::umax(const ConstantRange &Other) const {
   //                    umax(X_umax, Y_umax))
   if (isEmptySet() || Other.isEmptySet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
-  if (isFullSet() || Other.isFullSet())
-    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
   APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
   APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
   if (NewU == NewL)
diff --git a/llvm/unittests/Support/ConstantRangeTest.cpp b/llvm/unittests/Support/ConstantRangeTest.cpp
index ccac1801474..83bf5350283 100644
--- a/llvm/unittests/Support/ConstantRangeTest.cpp
+++ b/llvm/unittests/Support/ConstantRangeTest.cpp
@@ -184,7 +184,6 @@ TEST_F(ConstantRangeTest, SExt) {
                                  APInt(Some.getUpper()).sext(20)));
   EXPECT_EQ(SWrap, ConstantRange(APInt(Wrap.getLower()).sext(20),
                                  APInt(Wrap.getUpper()).sext(20)));
-
 }
 
 TEST_F(ConstantRangeTest, IntersectWith) {
@@ -285,9 +284,9 @@ TEST_F(ConstantRangeTest, Multiply) {
 TEST_F(ConstantRangeTest, UMax) {
   EXPECT_TRUE(Full.umax(Full).isFullSet());
   EXPECT_TRUE(Full.umax(Empty).isEmptySet());
-  EXPECT_TRUE(Full.umax(Some).isFullSet());
+  EXPECT_EQ(Full.umax(Some), ConstantRange(APInt(16, 0xa), APInt(16, 0)));
   EXPECT_TRUE(Full.umax(Wrap).isFullSet());
-  EXPECT_TRUE(Full.umax(One).isFullSet());
+  EXPECT_EQ(Full.umax(Some), ConstantRange(APInt(16, 0xa), APInt(16, 0)));
   EXPECT_EQ(Empty.umax(Empty), Empty);
   EXPECT_EQ(Empty.umax(Some), Empty);
   EXPECT_EQ(Empty.umax(Wrap), Empty);
@@ -304,19 +303,21 @@ TEST_F(ConstantRangeTest, UMax) {
 TEST_F(ConstantRangeTest, SMax) {
   EXPECT_TRUE(Full.smax(Full).isFullSet());
   EXPECT_TRUE(Full.smax(Empty).isEmptySet());
-  EXPECT_TRUE(Full.smax(Some).isFullSet());
+  EXPECT_EQ(Full.smax(Some), ConstantRange(APInt(16, 0xa),
+                             APInt::getSignedMinValue(16)));
   EXPECT_TRUE(Full.smax(Wrap).isFullSet());
-  EXPECT_TRUE(Full.smax(One).isFullSet());
+  EXPECT_EQ(Full.smax(One), ConstantRange(APInt(16, 0xa),
+                            APInt::getSignedMinValue(16)));
   EXPECT_EQ(Empty.smax(Empty), Empty);
   EXPECT_EQ(Empty.smax(Some), Empty);
   EXPECT_EQ(Empty.smax(Wrap), Empty);
   EXPECT_EQ(Empty.smax(One), Empty);
   EXPECT_EQ(Some.smax(Some), Some);
   EXPECT_EQ(Some.smax(Wrap), ConstantRange(APInt(16, 0xa),
-                                                 APInt(16, INT16_MIN)));
+                                           APInt(16, INT16_MIN)));
   EXPECT_EQ(Some.smax(One), Some);
   EXPECT_EQ(Wrap.smax(One), ConstantRange(APInt(16, 0xa),
-                                                APInt(16, INT16_MIN)));
+                                          APInt(16, INT16_MIN)));
   EXPECT_EQ(One.smax(One), One);
 }