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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - inlining a function into itself can result in references to version of variable from wrong frame"
href="https://bugs.llvm.org/show_bug.cgi?id=34242">34242</a>
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<th>Summary</th>
<td>inlining a function into itself can result in references to version of variable from wrong frame
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Interprocedural Optimizations
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>richard-llvm@metafoo.co.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, sanjoy@playingwithpointers.com
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<p>
<div>
<pre>Reduced miscompiled testcase: (reduced from libaf's af_pan.c)
define i32 @test(i1 %init, i8* %addr) {
bb:
%n = alloca i32
br i1 %init, label %store, label %load
store:
store i32 0, i32* %n
%cast = bitcast i32* %n to i8*
%v = call i32 @test(i1 0, i8* %cast)
ret i32 %v
load:
%castback = bitcast i8* %addr to i32*
%n.load = load i32, i32* %castback
ret i32 %n.load
}
After inlining, we get this:
define i32 @test(i1 %init, i8* %addr) {
bb:
%n.i = alloca i32
%n = alloca i32
br i1 %init, label %store, label %load
store: ; preds = %bb
store i32 0, i32* %n
%cast = bitcast i32* %n to i8*
%0 = bitcast i32* %n.i to i8*
call void @llvm.lifetime.start.p0i8(i64 4, i8* %0)
%n.load.i = load i32, i32* %n.i
%1 = bitcast i32* %n.i to i8*
call void @llvm.lifetime.end.p0i8(i64 4, i8* %1)
ret i32 %n.load.i
load: ; preds = %bb
%castback = bitcast i8* %addr to i32*
%n.load = load i32, i32* %castback
ret i32 %n.load
}
This is wrong: %n.load.i is a load of the *wrong variable*. We should be
loading %n, not %n.i.</pre>
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