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On 20/01/2018 18:16, hameeza ahmed wrote:<br>
<blockquote type="cite"
cite="mid:CAFMPKeb79PFUhJRLt+sVYqHUf46tcvncvbMRecNT5PbhRK-eTA@mail.gmail.com">
<div dir="ltr">Actually i am working on vector accelerator which
will perform those instructions which are non temporal.
<div><br>
</div>
<div>for instance if i have this loop</div>
<div><br>
</div>
<div>for(i=0;i<2048;i++)</div>
<div>a[i]=b[i]+c[i];</div>
<div><br>
</div>
<div>currently it emits following IR;</div>
<div><br>
</div>
<div><br>
</div>
<div>
<div> %0 = getelementptr inbounds [2048 x i32], [2048 x i32]*
@b, i64 0, i64 %index<br>
</div>
<div> %1 = bitcast i32* %0 to <16 x i32>*</div>
<div> %wide.load = load <16 x i32>, <16 x i32>*
%1, align 16, !tbaa !1</div>
<div> %8 = getelementptr inbounds [2048 x i32], [2048 x i32]*
@c, i64 0, i64 %index</div>
<div> %9 = bitcast i32* %8 to <16 x i32>*</div>
<div> %wide.load14 = load <16 x i32>, <16 x i32>*
%9, align 16, !tbaa !1</div>
<div> %16 = add nsw <16 x i32> %wide.load14, %wide.load</div>
<div> %20 = getelementptr inbounds [2048 x i32], [2048 x
i32]* @a, i64 0, i64 %index</div>
<div> %21 = bitcast i32* %20 to <16 x i32>*</div>
<div> store <16 x i32> %16, <16 x i32>* %21,
align 16, !tbaa !1</div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>However, i want it to emit following IR </div>
<div><br>
</div>
<div>
<div> %0 = getelementptr inbounds [2048 x i32], [2048 x i32]*
@b, i64 0, i64 %index<br>
</div>
<div> %1 = bitcast i32* %0 to <16 x i32>*</div>
<div> %wide.load = load <16 x i32>, <16 x i32>*
%1, align 16, !tbaa !1, !nontemporal !1</div>
<div> %8 = getelementptr inbounds [2048 x i32], [2048 x i32]*
@c, i64 0, i64 %index</div>
<div> %9 = bitcast i32* %8 to <16 x i32>*</div>
<div> %wide.load14 = load <16 x i32>, <16 x i32>*
%9, align 16, !tbaa !1, !nontemporal !1</div>
<div> %16 = add nsw <16 x i32> %wide.load14,
%wide.load, !nontemporal !1</div>
<div> %20 = getelementptr inbounds [2048 x i32], [2048 x
i32]* @a, i64 0, i64 %index</div>
<div> %21 = bitcast i32* %20 to <16 x i32>*</div>
<div> store <16 x i32> %16, <16 x i32>* %21,
align 16, !tbaa !1, !nontemporal !1</div>
</div>
<div><br>
</div>
<div>so that i can offload load, add, store to accelerator
hardware. is it possible here? do i need a separate pass to
detect whether the loop has non temporal data or polly will
help here? what do you say?</div>
</div>
</blockquote>
From C/C++ you just need to use the
__builtin_nontemporal_store/__builtin_nontemporal_load builtins to
tag the stores/loads with the nontemporal flag.<br>
<br>
<div>for(i=0;i<2048;i++) {<br>
</div>
<div> __builtin_nontemporal_store( __builtin_nontemporal_load(b+i)
+ __builtin_nontemporal_load(c + i), a + i );<br>
</div>
<div>}<br>
</div>
<br>
There may be an attribute you can tag pointers with instead but I
don't know off hand.<br>
<br>
<blockquote type="cite"
cite="mid:CAFMPKeb79PFUhJRLt+sVYqHUf46tcvncvbMRecNT5PbhRK-eTA@mail.gmail.com">
<div class="gmail_extra">On Sat, Jan 20, 2018 at 11:02 PM, Simon
Pilgrim <span dir="ltr"><<a
href="mailto:llvm-dev@redking.me.uk" target="_blank"
moz-do-not-send="true">llvm-dev@redking.me.uk</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb">
<div class="h5">On 20/01/2018 17:44, hameeza ahmed via
llvm-dev wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello,<br>
<br>
My work deals with non-temporal loads and stores i
found non-temporal meta data in llvm documentation but
its not shown in IR.<br>
<br>
How to get non-temporal meta data?<br>
</blockquote>
</div>
</div>
llvm\test\CodeGen\X86\nontempo<wbr>ral-loads.ll shows how to
create nt vector loads in IR - is that what you're after?<span
class="HOEnZb"><font color="#888888"><br>
<br>
Simon.<br>
</font></span></blockquote>
</div>
<br>
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</blockquote>
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