BasicBlocks whose `bbJumpKind` doesn't make use of `bbJumpDest` may have
arbitrary garbage in their `bbJumpDest` field, so remove the code from
loop unrolling that was expecting such blocks to have null `bbJumpDest`s,
and instead always defer to the `optCopyBlkDest`/`optRedirectBlock`
helpers that check the jump kind before checking the jump dest.
Fixes dotnet/coreclr#8231.
Commit migrated from https://github.com/dotnet/coreclr/commit/
9130174cbef365c84b48002d6899f3ea9ec55df4
// Now redirect any branches within the newly-cloned iteration
for (block = head->bbNext; block != bottom; block = block->bbNext)
{
- if (BasicBlock* oldDest = block->bbJumpDest)
- {
- BasicBlock* newBlock = blockMap[block];
- BasicBlock* newDest;
- if (!blockMap.Lookup(oldDest, &newDest))
- {
- // This was a loop exit; route to the same exit
- newDest = oldDest;
- }
-
- newBlock->bbJumpDest = newDest;
- }
- else if (block->bbJumpKind == BBJ_SWITCH)
- {
- BasicBlock* newBlock = blockMap[block];
- assert(newBlock->bbJumpKind == BBJ_SWITCH);
- optCopyBlkDest(block, newBlock);
- optRedirectBlock(newBlock, &blockMap);
- }
+ BasicBlock* newBlock = blockMap[block];
+ optCopyBlkDest(block, newBlock);
+ optRedirectBlock(newBlock, &blockMap);
}
/* update the new value for the unrolled iterator */
--- /dev/null
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+
+namespace N
+{
+ public static class C
+ {
+ // This is a regression test for a failure in loop unrolling when
+ // the unrolled loop contains a switch statement.
+ [MethodImpl(MethodImplOptions.NoInlining)]
+ static int Test()
+ {
+ int s = 0;
+
+ // Loop to some Vector<T>.Count to trigger unrolling.
+ for (int i = 0; i < Vector<int>.Count; i++)
+ {
+ // Loop contains switch; the bug was that the clones
+ // of the switch were all sharing its BBswtDesc instead
+ // of getting their own, so updates to their jump targets
+ // were incorrectly shared.
+ switch (i)
+ {
+ case 1: s += 4; break;
+ case 2: s += 2; break;
+ case 3: s += i; break;
+ }
+ }
+
+ return s;
+ }
+
+ public static int Main(string[] args)
+ {
+ int result = Test();
+
+ // Expected result is a function of Vector<int>.Count.
+ int expected;
+ switch(Vector<int>.Count)
+ {
+ case 1:
+ expected = 4;
+ break;
+ case 2:
+ expected = 6;
+ break;
+ default:
+ expected = 9;
+ break;
+ }
+
+ // Return 100 on success (result == expected), other
+ // values on failure.
+ return 100 + result - expected;
+ }
+ }
+}
--- /dev/null
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+ <ItemGroup>
+ <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
+ </ItemGroup>
+ <ItemGroup>
+ <Compile Include="GitHub_8231.cs" />
+ </ItemGroup>
+ <PropertyGroup>
+ <ProjectJson>$(JitPackagesConfigFileDirectory)benchmark\project.json</ProjectJson>
+ <ProjectLockJson>$(JitPackagesConfigFileDirectory)benchmark\project.lock.json</ProjectLockJson>
+ </PropertyGroup>
+ <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
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+ </PropertyGroup>
+</Project>