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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [GISEL] Error legalising neon type at -O0 on AArch64."
href="https://bugs.llvm.org/show_bug.cgi?id=40958">40958</a>
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<th>Summary</th>
<td>[GISEL] Error legalising neon type at -O0 on AArch64.
</td>
</tr>
<tr>
<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>Linux
</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>GlobalISel
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>david.green@arm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, Matthew.Arsenault@amd.com, quentin.colombet@gmail.com
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<p>
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<pre>This code:
typedef __attribute__((neon_vector_type(4))) float float32x4_t;
typedef struct {
float32x4_t b;
float32x4_t c;
} d;
void e() {
d f = {0,0};
g(f);
}
Fails during legalisation under:
clang -O0 -target aarch64-linux-gnu -mcpu=cortex-a57 -c 20150303004327-180.c
-mllvm -verify-machineinstrs
With incorrect element types on:
%12:_(<4 x s32>) = G_BUILD_VECTOR %28:_(s64), %30:_(s64)
Without the verify-machineinstrs, it runs into an illegal register copy during
reg alloc.
Bisecting this led back to rL353121, but it may be a knock on effect. I don't
read global isel debug output very well yet. Perhaps it's the narrowing of the
extract that's wrong, not the combining?
The same thing in IR:
; Function Attrs: noinline nounwind optnone
define dso_local void @e() #0 {
entry:
%f = alloca %struct.d, align 16
%0 = bitcast %struct.d* %f to i8*
call void @llvm.memset.p0i8.i64(i8* align 16 %0, i8 0, i64 32, i1 false)
%1 = bitcast %struct.d* %f to [2 x <4 x float>]*
%2 = load [2 x <4 x float>], [2 x <4 x float>]* %1, align 16
%call = call i32 bitcast (i32 (...)* @g to i32 ([2 x <4 x float>])*)([2 x <4
x float>] %2)
ret void
}</pre>
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