From: Hyeongseok Oh <hseok82.oh@samsung.com>
Date: Tue, 24 Oct 2017 07:36:04 +0000 (+0900)
Subject: Fix callee argument count bug in fgCanFastTailCall
X-Git-Tag: accepted/tizen/base/20180629.140029~781^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1596287ad5c994d5ea76aba90066d408d2a965fa;p=platform%2Fupstream%2Fcoreclr.git

Fix callee argument count bug in fgCanFastTailCall

Fix bug when callee uses return buffer:
return buffer argument is already generated in callee->gtCallArgs on import phase
So we should not increment calleeArgRegCount explicitly.
---

diff --git a/src/jit/morph.cpp b/src/jit/morph.cpp
index 42c5a2a..81b25ec 100644
--- a/src/jit/morph.cpp
+++ b/src/jit/morph.cpp
@@ -7295,7 +7295,7 @@ bool Compiler::fgCanFastTailCall(GenTreeCall* callee)
 
     if (callee->HasRetBufArg()) // RetBuf
     {
-        ++calleeArgRegCount;
+        // We don't increment calleeArgRegCount here, since it is already in callee->gtCallArgs.
 
         // If callee has RetBuf param, caller too must have it.
         // Otherwise go the slow route.