From: Hyeongseok Oh <hseok82.oh@samsung.com>
Date: Mon, 20 Mar 2017 06:26:33 +0000 (+0900)
Subject: [ARM32/Linux] Fix register allocation for null check in call instruction
X-Git-Tag: accepted/tizen/base/20180629.140029~1576^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dd130b56246b8854fb711bcb32839b398eb240ee;p=platform%2Fupstream%2Fcoreclr.git

[ARM32/Linux] Fix register allocation for null check in call instruction

Fix assertion when two temporary registers are reserved in call instruction
---

diff --git a/src/jit/codegenarm.cpp b/src/jit/codegenarm.cpp
index e276b71..b5e3313 100644
--- a/src/jit/codegenarm.cpp
+++ b/src/jit/codegenarm.cpp
@@ -1952,8 +1952,13 @@ void CodeGen::genCallInstruction(GenTreeCall* call)
     // Insert a null check on "this" pointer if asked.
     if (call->NeedsNullCheck())
     {
-        const regNumber regThis = genGetThisArgReg(call);
-        const regNumber tmpReg  = genRegNumFromMask(call->gtRsvdRegs);
+        const regNumber regThis  = genGetThisArgReg(call);
+        regMaskTP       tempMask = genFindLowestBit(call->gtRsvdRegs);
+        const regNumber tmpReg   = genRegNumFromMask(tempMask);
+        if (genCountBits(call->gtRsvdRegs) > 1)
+        {
+            call->gtRsvdRegs &= ~tempMask;
+        }
         getEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, tmpReg, regThis, 0);
     }