[InstCombine][TLI] Fix function prototype of `labs` (#69077)

`i64 @labs(i32)` is incorrectly recognized as `LibFunc_labs` because
type ID `Long` matches both `i32` and `i64`. This PR requires the type
of argument to match the return value.

Fixes #69059.

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
index 8c2328e..292b5ca 100644
--- a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
+++ b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
@@ -69,6 +69,16 @@ TEST_F(TargetLibraryInfoTest, InvalidProto) {
         M->getOrInsertFunction(TLI.getName(LF), InvalidFTy).getCallee());
     EXPECT_FALSE(isLibFunc(F, LF));
   }
+
+  // i64 @labs(i32)
+  {
+    auto *InvalidLabsFTy = FunctionType::get(Type::getInt64Ty(Context),
+                                             {Type::getInt32Ty(Context)},
+                                             /*isVarArg=*/false);
+    auto *F = cast<Function>(
+        M->getOrInsertFunction("labs", InvalidLabsFTy).getCallee());
+    EXPECT_FALSE(isLibFunc(F, LibFunc_labs));
+  }
 }
 
 // Check that we do accept know-correct prototypes.