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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Different types share the same TBAA descriptor"
href="https://bugs.llvm.org/show_bug.cgi?id=35703">35703</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Different types share the same TBAA descriptor
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</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>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>sepavloff@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Run commands:
$ cat bug-02.c
typedef struct {
short f16;
int f32;
} ABC;
typedef struct {
short v16;
int v32;
} CDE;
void func(ABC *A, CDE *B) {
A->f32 = 4;
B->v32 = 44;
}
$ clang -S -emit-llvm -O1 bug-02.c
The resulting .ll file contains:
%struct.ABC = type { i16, i32 }
%struct.CDE = type { i16, i32 }
; Function Attrs: norecurse nounwind uwtable
define void @func(%struct.ABC* nocapture %A, %struct.CDE* nocapture %B)
local_unnamed_addr #0 {
entry:
%f32 = getelementptr inbounds %struct.ABC, %struct.ABC* %A, i64 0, i32 1
store i32 4, i32* %f32, align 4, !tbaa !2
%v32 = getelementptr inbounds %struct.CDE, %struct.CDE* %B, i64 0, i32 1
store i32 44, i32* %v32, align 4, !tbaa !2
ret void
}
...
!2 = !{!3, !7, i64 4}
!3 = !{!"", !4, i64 0, !7, i64 4}
!4 = !{!"short", !5, i64 0}
!5 = !{!"omnipotent char", !6, i64 0}
!6 = !{!"Simple C/C++ TBAA"}
!7 = !{!"int", !5, i64 0}
Two different types use the same descriptor (!3). In C++ mode there is no such
problem, types get their names from typedef names.</pre>
</div>
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