ValueTracking: Use fcAllFlags for unknown value (#66393)

In the failure case we return null, which callers are checking. We were
also returning an fcNone which was unused. It's more consistent to
return fcAllFlags as any possible value, such that the value is always
directly usable without checking the returned value.

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
index 4eed22d..5bd1bb3 100644
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -1848,13 +1848,13 @@ TEST_F(ComputeKnownFPClassTest, FCmpToClassTest_NInf) {
       fcmpToClassTest(CmpInst::FCMP_OGT, *A3->getFunction(), A3->getOperand(0),
                       A3->getOperand(1));
   EXPECT_EQ(nullptr, OgtVal);
-  EXPECT_EQ(fcNone, OgtClass);
+  EXPECT_EQ(fcAllFlags, OgtClass);
 
   auto [UleVal, UleClass] =
       fcmpToClassTest(CmpInst::FCMP_ULE, *A4->getFunction(), A4->getOperand(0),
                       A4->getOperand(1));
   EXPECT_EQ(nullptr, UleVal);
-  EXPECT_EQ(fcNone, UleClass);
+  EXPECT_EQ(fcAllFlags, UleClass);
 }
 
 TEST_F(ComputeKnownFPClassTest, FCmpToClassTest_PInf) {
@@ -1881,13 +1881,13 @@ TEST_F(ComputeKnownFPClassTest, FCmpToClassTest_PInf) {
       fcmpToClassTest(CmpInst::FCMP_OLE, *A3->getFunction(), A3->getOperand(0),
                       A3->getOperand(1));
   EXPECT_EQ(nullptr, OleVal);
-  EXPECT_EQ(fcNone, OleClass);
+  EXPECT_EQ(fcAllFlags, OleClass);
 
   auto [UgtVal, UgtClass] =
       fcmpToClassTest(CmpInst::FCMP_UGT, *A4->getFunction(), A4->getOperand(0),
                       A4->getOperand(1));
   EXPECT_EQ(nullptr, UgtVal);
-  EXPECT_EQ(fcNone, UgtClass);
+  EXPECT_EQ(fcAllFlags, UgtClass);
 }
 
 TEST_F(ComputeKnownFPClassTest, SqrtNszSignBit) {