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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wasm32: Lowering of i32x4.lt may not handle sign extension"
href="https://bugs.llvm.org/show_bug.cgi?id=39273">39273</a>
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<th>Summary</th>
<td>wasm32: Lowering of i32x4.lt may not handle sign extension
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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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>Windows NT
</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>Backend: WebAssembly
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>alex@crichton.co
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, tlively@google.com
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<p>
<div>
<pre>It looks like many of the comparison operations for wasm SIMD are all
implemented (nice!) but the tests largely return <4 x i1>. In the bindings
we're thinking of writing we'd like to match the intrinsics themselves in wasm,
which means returning <4 x i32>, and to that end we generate the following IR:
; ModuleID = 'foo.3a1fbbbh-cgu.0'
source_filename = "foo.3a1fbbbh-cgu.0"
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
; Function Attrs: norecurse nounwind readnone
define <4 x i32> @simd_lt(<4 x i32> %a, <4 x i32> %b) unnamed_addr #0 {
start:
%0 = icmp eq <4 x i32> %a, %b
%1 = sext <4 x i1> %0 to <4 x i32>
ret <4 x i32> %1
}
attributes #0 = { norecurse nounwind readnone "target-features"="+simd128" }
when compiled though this yields:
$ llc foo.ll -filetype=obj
LLVM ERROR: Cannot select: t15: v4i32 = sign_extend_inreg t13,
ValueType:ch:v4i1
t13: v4i32 = setcc t2, t4, seteq:ch
t2: v4i32 = WebAssemblyISD::ARGUMENT TargetConstant:i32<0>
t1: i32 = TargetConstant<0>
t4: v4i32 = WebAssemblyISD::ARGUMENT TargetConstant:i32<1>
t3: i32 = TargetConstant<1>
In function: simd_lt
This may not be the desired pattern though used to bind these intrinsics! We
certainly don't mind switching to different codegen.</pre>
</div>
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