<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [X86][SSE] Improve insertelement-zero.ll + insertelement-ones.ll codegen"
href="https://bugs.llvm.org/show_bug.cgi?id=39456">39456</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[X86][SSE] Improve insertelement-zero.ll + insertelement-ones.ll codegen
</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>
<tr>
<th>OS</th>
<td>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>andrea.dibiagio@gmail.com, craig.topper@gmail.com, llvm-bugs@lists.llvm.org, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre>The insertion of 0/-1 elements into vectors can often be more efficiently
performed as either a blend with a rematerializable 0/-1 vector or with an
AND/OR op with a constant mask:
define <32 x i8> @insert_v32i8_z123456789ABCDEzGHIJKLMNOPQRSTzz(<32 x i8> %a) {
; AVX1-LABEL: insert_v32i8_z123456789ABCDEzGHIJKLMNOPQRSTzz:
; AVX1: # %bb.0:
; AVX1-NEXT: xorl %eax, %eax
; AVX1-NEXT: vpinsrb $0, %eax, %xmm0, %xmm1
; AVX1-NEXT: vpinsrb $15, %eax, %xmm1, %xmm1
; AVX1-NEXT: vextractf128 $1, %ymm0, %xmm0
; AVX1-NEXT: vpxor %xmm2, %xmm2, %xmm2
; AVX1-NEXT: vpblendw {{.*#+}} xmm0 = xmm0[0,1,2,3,4,5,6],xmm2[7]
; AVX1-NEXT: vinsertf128 $1, %xmm0, %ymm1, %ymm0
; AVX1-NEXT: retq
;
; AVX2-SLOW-LABEL: insert_v32i8_z123456789ABCDEzGHIJKLMNOPQRSTzz:
; AVX2-SLOW: # %bb.0:
; AVX2-SLOW-NEXT: xorl %eax, %eax
; AVX2-SLOW-NEXT: vpinsrb $0, %eax, %xmm0, %xmm1
; AVX2-SLOW-NEXT: vpinsrb $15, %eax, %xmm1, %xmm1
; AVX2-SLOW-NEXT: vextracti128 $1, %ymm0, %xmm0
; AVX2-SLOW-NEXT: vpxor %xmm2, %xmm2, %xmm2
; AVX2-SLOW-NEXT: vpblendw {{.*#+}} xmm0 = xmm0[0,1,2,3,4,5,6],xmm2[7]
; AVX2-SLOW-NEXT: vinserti128 $1, %xmm0, %ymm1, %ymm0
; AVX2-SLOW-NEXT: retq
;
; AVX2-FAST-LABEL: insert_v32i8_z123456789ABCDEzGHIJKLMNOPQRSTzz:
; AVX2-FAST: # %bb.0:
; AVX2-FAST-NEXT: vpand {{.*}}(%rip), %xmm0, %xmm1
; AVX2-FAST-NEXT: vextracti128 $1, %ymm0, %xmm0
; AVX2-FAST-NEXT: vpxor %xmm2, %xmm2, %xmm2
; AVX2-FAST-NEXT: vpblendw {{.*#+}} xmm0 = xmm0[0,1,2,3,4,5,6],xmm2[7]
; AVX2-FAST-NEXT: vinserti128 $1, %xmm0, %ymm1, %ymm0
; AVX2-FAST-NEXT: retq
%1 = insertelement <32 x i8> %a, i8 0, i32 0
%2 = insertelement <32 x i8> %1, i8 0, i32 15
%3 = insertelement <32 x i8> %2, i8 0, i32 30
%4 = insertelement <32 x i8> %3, i8 0, i32 31
ret <32 x i8> %4
}
Not even the AVX2-FAST cases properly manages to see that this is just a AND
mask.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>