[arm32] Assertion failed 'genIsValidIntReg(dstReg)'

[echesakov]

It seems that this has been broken for a while. I recently caught this during PR dotnet/coreclr#18289 testing
But the regression was introduced earlier - sometime between Build dotnet/coreclr#18 (May 17, 2018 4:32:43 AM) and Build dotnet/coreclr#19 (May 24, 2018 4:27:51 AM)

----- start 23:20:10 =============== To repro directly: =====================================================
pushd .
#!/usr/bin/env bash
chmod +x /ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/testhost/netcoreapp-Linux-Release-arm/dotnet
/ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/testhost/netcoreapp-Linux-Release-arm/dotnet xunit.console.netcore.exe System.Dynamic.Runtime.Tests.dll  -xml testResults.xml -notrait Benchmark=true -notrait category=nonnetcoreapptests -notrait category=nonlinuxtests  -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing
popd
===========================================================================================================
/ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/tests/System.Dynamic.Runtime.Tests/netcoreapp-Linux-Release-arm /ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/tests/System.Dynamic.Runtime.Tests/netcoreapp-Linux-Release-arm
xUnit.net console test runner (32-bit .NET Core)
Copyright (C) 2014 Outercurve Foundation.

Discovering: System.Dynamic.Runtime.Tests
Discovered:  System.Dynamic.Runtime.Tests
Starting:    System.Dynamic.Runtime.Tests

Assert failure(PID 12372 [0x00003054], Thread: 12387 [0x3063]): Assertion failed 'genIsValidIntReg(dstReg)' in 'DynamicClass:CallSite.Target(ref,ref,ref,ref):ref' (IL size 143)

    File: /mnt/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_prtest/src/jit/codegenarmarch.cpp Line: 3406
    Image: /ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/testhost/netcoreapp-Linux-Release-arm/dotnet


Assert failure(PID 12372 [0x00003054], Thread: 12387 [0x3063]): Assertion failed 'genIsValidIntReg(dstReg)' in 'DynamicClass:CallSite.Target(ref,ref,ref,ref):ref' (IL size 143)

    File: /mnt/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_prtest/src/jit/codegenarmarch.cpp Line: 3406
    Image: /ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/testhost/netcoreapp-Linux-Release-arm/dotnet

./RunTests.sh: line 126: 12372 Aborted                 $RUNTIME_PATH/dotnet xunit.console.netcore.exe System.Dynamic.Runtime.Tests.dll -xml testResults.xml -notrait Benchmark=true -notrait category=nonnetcoreapptests -notrait category=nonlinuxtests -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing
/ssd/j/workspace/dotnet_coreclr/master/jitstress/arm_cross_checked_ubuntu_corefx_baseline_tst_prtest/_/fx/bin/tests/System.Dynamic.Runtime.Tests/netcoreapp-Linux-Release-arm
----- end 23:22:29 ----- exit code 134 ----------------------------------------------------------

Update: The issue is also reproducible on Windows/ARM (e.g. https://ci.dot.net/job/dotnet_coreclr/job/master/view/arm/job/jitstress/job/arm_cross_checked_windows_nt_corefx_baseline_tst/21/consoleText)

When the issue is resolved enable back tests disabled in PR dotnet/coreclr#18347

[echesakov]

@dotnet/jit-contrib

[echesakov]

Also reproducible on Windows/arm in System.Linq.Expressions.Tests under JitStress=2

===========================================================================================================

C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\tests\System.Linq.Expressions.Tests\netcoreapp-Windows_NT-Release-arm>set COMPlus_JitStress=2 

C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\tests\System.Linq.Expressions.Tests\netcoreapp-Windows_NT-Release-arm>call C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\testhost\netcoreapp-Windows_NT-Release-arm\dotnet.exe xunit.console.netcore.exe System.Linq.Expressions.Tests.dll  -xml testResults.xml -notrait Benchmark=true -notrait category=nonnetcoreapptests -notrait category=nonwindowstests  -notrait category=IgnoreForCI -notrait category=OuterLoop -notrait category=failing 
xUnit.net console test runner (32-bit .NET Core)
Copyright (C) 2014 Outercurve Foundation.

Discovering: System.Linq.Expressions.Tests
Discovered:  System.Linq.Expressions.Tests
Starting:    System.Linq.Expressions.Tests

Assert failure(PID 20140 [0x00004eac], Thread: 10168 [0x27b8]): Assertion failed 'genIsValidIntReg(dstReg)' in 'DynamicClass:lambda_method(ref):bool' (IL size 56)

    File: d:\j\workspace\arm_cross_che---f3754642\src\jit\codegenarmarch.cpp Line: 3395
    Image: C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\testhost\netcoreapp-Windows_NT-Release-arm\dotnet.exe

----- end 11:58:54.13 ----- exit code 123456789 ----------------------------------------------------------
COREFX TEST FAILED
Running: C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\tests\System.Linq.Parallel.Performance.Tests\netcoreapp-Windows_NT-Release-arm\RunTests.cmd C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\testhost\netcoreapp-Windows_NT-Release-arm
Using C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\testhost\netcoreapp-Windows_NT-Release-arm as the test runtime folder.
Executing in C:\Users\robox\j\workspace\arm_cross_che---0fb8fec2\_\fx\bin\tests\System.Linq.Parallel.Performance.Tests\netcoreapp-Windows_NT-Release-arm\ 
----- start 11:58:54.25 ===============  To repro directly: ===================================================== 

[CarolEidt]

Confirmed that dotnet/coreclr#18561 fixes this on arm/linux