From: Carol Eidt <carol.eidt@microsoft.com>
Date: Tue, 19 Jun 2018 20:35:02 +0000 (-0700)
Subject: Fix struct promotion check for SIMD field (dotnet/coreclr#18548)
X-Git-Tag: submit/tizen/20210909.063632~11030^2~4565
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dcaeb4d99835fb4929ef65afc8d70b0817229879;p=platform%2Fupstream%2Fdotnet%2Fruntime.git

Fix struct promotion check for SIMD field (dotnet/coreclr#18548)

A struct can have `lvIsRegArg` true but have multiple SIMD fields if it is passed by reference.

Commit migrated from https://github.com/dotnet/coreclr/commit/d3905518d08ca174ae631aebfe16314b885aa61a
---

diff --git a/src/coreclr/src/jit/lclvars.cpp b/src/coreclr/src/jit/lclvars.cpp
index e0e8f74..b36fcad 100644
--- a/src/coreclr/src/jit/lclvars.cpp
+++ b/src/coreclr/src/jit/lclvars.cpp
@@ -2011,7 +2011,7 @@ void Compiler::lvaPromoteStructVar(unsigned lclNum, lvaStructPromotionInfo* Stru
             fieldVarDsc->lvArgReg   = varDsc->lvArgReg;
             fieldVarDsc->setPrefReg(varDsc->lvArgReg, this); // Set the preferred register
 #if FEATURE_MULTIREG_ARGS && defined(FEATURE_SIMD)
-            if (varTypeIsSIMD(fieldVarDsc))
+            if (varTypeIsSIMD(fieldVarDsc) && !lvaIsImplicitByRefLocal(lclNum))
             {
                 // This field is a SIMD type, and will be considered to be passed in multiple registers
                 // if the parent struct was. Note that this code relies on the fact that if there is