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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - MSVC: "A single unwind edge may only enter one EH pad""
href="https://llvm.org/bugs/show_bug.cgi?id=27568">27568</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>MSVC: "A single unwind edge may only enter one EH pad"
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Interprocedural Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>alex@crichton.co
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following IR will fail to compile when compiled with `opt foo.ll -S
-argpromotion`
```
; ModuleID = 'tmp.ll'
target triple = "x86_64-pc-windows-msvc"
%FOO = type { %BAR, i32 }
%BAR = type { i32* }
define void @foo() personality i32 (...)* @__CxxFrameHandler3 {
entry-block:
%foo = alloca %FOO
%slot1 = getelementptr %FOO, %FOO* %foo, i64 0, i32 0
%slot2 = getelementptr %FOO, %FOO* %foo, i64 0, i32 1
invoke fastcc void @thunk(i32* %slot2)
to label %good1 unwind label %bad1
good1: ; preds = %entry-block
ret void
bad1: ; preds = %entry-block
%pad1 = cleanuppad within none []
invoke fastcc void @bar(%BAR* %slot1) [ "funclet"(token %pad1) ]
to label %good2 unwind label %bad2
good2: ; preds = %bad1
cleanupret from %pad1 unwind to caller
bad2: ; preds = %bad1
%pad2 = cleanuppad within %pad1 []
%ptr1 = getelementptr %BAR, %BAR* %slot1, i64 0, i32 0
%ptr2 = load i32*, i32** %ptr1
call void @thunk(i32* %ptr2) [ "funclet"(token %pad2) ]
cleanupret from %pad2 unwind to caller
}
define internal void @bar(%BAR*) {
entry-block:
%1 = getelementptr %BAR, %BAR* %0, i32 0, i32 0
%2 = load i32*, i32** %1
call void @thunk(i32* %2)
ret void
}
declare void @thunk(i32*)
declare i32 @__CxxFrameHandler3(...)
```
This is heavily reduced down from a test case in Rust, but I can try to get
more context if necessary as well, so please just let me know if any more is
needed!</pre>
</div>
</p>
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