JIT: recognize we have exact type for this in constructors

In constructors the exact type of `this` is known. Tracking this helps the jit devirtualize calls made from chaining constructors. Related discussion in #16198.
AndyAyersMS · Feb 6, 2018 · 1464a16 · 1464a16
1 parent 4e617da
commit 1464a16
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/src/jit/lclvars.cpp b/src/jit/lclvars.cpp
@@ -412,8 +412,9 @@ void Compiler::lvaInitThisPtr(InitVarDscInfo* varDscInfo)
         }
         else
         {
-            varDsc->lvType = TYP_REF;
-            lvaSetClass(varDscInfo->varNum, info.compClassHnd);
+            const bool isExact = (info.compFlags & CORINFO_FLG_CONSTRUCTOR) != 0;
+            varDsc->lvType     = TYP_REF;
+            lvaSetClass(varDscInfo->varNum, info.compClassHnd, isExact);
         }
 
         if (tiVerificationNeeded)