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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Alignment assumptions prevent SROA"
href="https://bugs.llvm.org/show_bug.cgi?id=45763">45763</a>
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<th>Summary</th>
<td>Alignment assumptions prevent SROA
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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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>Scalar Optimizations
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>nikita.ppv@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, Matthew.Arsenault@amd.com, stanislav.mekhanoshin@amd.com
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<pre>As reported in <a href="https://reviews.llvm.org/D76886#2008588">https://reviews.llvm.org/D76886#2008588</a>:
; RUN: opt -S -O3 -preserve-alignment-assumptions-during-inlining=true < %s |
FileCheck %s
; CHECK: @caller
; CHECK-NOT: alloca
; CHECK-NEXT: ret void
target datalayout = "e-p:64:64-p5:32:32-A5"
define amdgpu_kernel void @caller() {
%alloca = alloca i64, align 8, addrspace(5)
%cast = addrspacecast i64 addrspace(5)* %alloca to i64*
call void @callee(i64* sret align 8 %cast)
ret void
}
define internal void @callee(i64* noalias sret align 8 %arg) {
store i64 0, i64* %arg, align 8
ret void
}
This results in:
target datalayout = "e-p:64:64-p5:32:32-A5"
define amdgpu_kernel void @caller() local_unnamed_addr {
%alloca = alloca i64, align 8, addrspace(5)
%cast = addrspacecast i64 addrspace(5)* %alloca to i64*
%ptrint = ptrtoint i64* %cast to i64
%maskedptr = and i64 %ptrint, 7
%maskcond = icmp eq i64 %maskedptr, 0
call void @llvm.assume(i1 %maskcond)
ret void
}
declare void @llvm.assume(i1)
The ptrtoint this introduces prevents SROA.
Likely the solution to this is not a change to SROA, but a change to the
representation of alignment assumptions (via assume bundles).</pre>
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