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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 - New byval verification check fails after PGO indirect call promotion pass"
href="https://bugs.llvm.org/show_bug.cgi?id=42413">42413</a>
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<th>Summary</th>
<td>New byval verification check fails after PGO indirect call promotion pass
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<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>Miscellaneous Instrumentation passes
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>rnk@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, t.p.northover@gmail.com, xur@google.com
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<p>
<div>
<pre>Consider this test case:
; t.ll
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.Foo.1 = type { i32 }
%struct.Foo.2 = type { i32 }
@foo = common global i32 (%struct.Foo.2*)* null, align 8
define i32 @func4(%struct.Foo.1* byval(%struct.Foo.1) %p) {
entry:
%gep = getelementptr inbounds %struct.Foo.1, %struct.Foo.1* %p, i32 0, i32 0
%v = load i32, i32* %gep
ret i32 %v
}
define i32 @bar(%struct.Foo.2* %f2) {
entry:
%tmp = load i32 (%struct.Foo.2*)*, i32 (%struct.Foo.2*)** @foo, align 8
%call = call i32 %tmp(%struct.Foo.2* byval(%struct.Foo.2) %f2), !prof !1
ret i32 %call
}
!1 = !{!"VP", i32 0, i64 1600, i64 7651369219802541373, i64 1030, i64
-4377547752858689819, i64 410, i64 -6929281286627296573, i64 150, i64
-2545542355363006406, i64 10}
$ opt -pgo-icall-prom -S < t.ll -icp-total-percent-threshold=50
Attribute 'byval' type does not match parameter!
%2 = call i32 @func4(%struct.Foo.1* byval(%struct.Foo.2) %1)
in function bar
The issue is that llvm::promoteCall in
llvm/lib/Transforms/Utils/CallPromotion.cpp simply mutates the function type
and inserts pointer casts as necessary, without considering the recently added
byval attribute type.
The question is, is the verifier check too strict? Should the IR produced by
this pass be invalid? In the desired end state, pointers will not have types,
and this code won't have to insert pointer casts, and the verifier won't even
be able to compare the byval types. I think we're in an intermediate state. For
now, we can of course update the code, but I felt it was worth filing a bug to
consider the larger issue.</pre>
</div>
</p>
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