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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Assertion `(LocalChanged || (RefHash == StructuralHash(F))) && "Pass modifies its input and doesn't report it."' for -gvn pass"
href="https://bugs.llvm.org/show_bug.cgi?id=47378">47378</a>
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<th>Summary</th>
<td>Assertion `(LocalChanged || (RefHash == StructuralHash(F))) && "Pass modifies its input and doesn't report it."' for -gvn pass
</td>
</tr>
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<th>Product</th>
<td>new-bugs
</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>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>david.stenberg@ericsson.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=23910" name="attach_23910" title="IR reproducer.">attachment 23910</a> <a href="attachment.cgi?id=23910&action=edit" title="IR reproducer.">[details]</a></span>
IR reproducer.
LLVM commit: 113861b444610aebd1c05760a3e0ee6284f42211
Requires an expensive checks build to reproduce.
$ opt -S -gvn gvn.ll
Pass modifies its input and doesn't report it: Global Value Numbering
Pass modifies its input and doesn't report it
UNREACHABLE executed at ../lib/IR/LegacyPassManager.cpp:1525!
Code change that the pass produces without the assertion enabled:
@@ -15,6 +18,7 @@
%2 = load i16, i16* @b, align 1
%inc = add nsw i16 %2, 1
store i16 %inc, i16* @b, align 1
+ %.pre = trunc i32 %0 to i16
br label %if.end
if.else: ; preds = %entry
@@ -23,10 +27,10 @@
br label %if.end
if.end: ; preds = %if.else, %if.then
- %3 = trunc i32 %0 to i16
- %arrayidx = getelementptr inbounds [1 x i16], [1 x i16]* @c, i16 0, i16 %3
- %4 = load i16, i16* %arrayidx, align 1
- store i16 %4, i16* @b, align 1
+ %.pre-phi = phi i16 [ %conv, %if.else ], [ %.pre, %if.then ]
+ %arrayidx = getelementptr inbounds [1 x i16], [1 x i16]* @c, i16 0, i16
%.pre-phi
+ %3 = load i16, i16* %arrayidx, align 1
+ store i16 %3, i16* @b, align 1
ret i16 undef
}@@ -15,6 +18,7 @@
%2 = load i16, i16* @b, align 1
%inc = add nsw i16 %2, 1
store i16 %inc, i16* @b, align 1
+ %.pre = trunc i32 %0 to i16
br label %if.end
if.else: ; preds = %entry
@@ -23,10 +27,10 @@
br label %if.end
if.end: ; preds = %if.else, %if.then
- %3 = trunc i32 %0 to i16
- %arrayidx = getelementptr inbounds [1 x i16], [1 x i16]* @c, i16 0, i16 %3
- %4 = load i16, i16* %arrayidx, align 1
- store i16 %4, i16* @b, align 1
+ %.pre-phi = phi i16 [ %conv, %if.else ], [ %.pre, %if.then ]
+ %arrayidx = getelementptr inbounds [1 x i16], [1 x i16]* @c, i16 0, i16
%.pre-phi
+ %3 = load i16, i16* %arrayidx, align 1
+ store i16 %3, i16* @b, align 1
ret i16 undef
}</pre>
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