<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 14, 2017 at 9:59 PM, vivek pandya <span dir="ltr"><<a href="mailto:vivekvpandya@gmail.com" target="_blank">vivekvpandya@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="gmail-">On Tue, Mar 14, 2017 at 7:19 PM, Hal Finkel <span dir="ltr"><<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF"><span>
<p><br>
</p>
<div class="gmail-m_-893470938952784482m_4013586522218816313moz-cite-prefix">On 03/14/2017 07:16 AM, vivek pandya
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hello Hal,
<div>setCondCodeAction(expand) for un ordered comparison
generates semantically wrong code for me for example SETUNE
gets converted to SETOE that causes infinite loops.</div>
</div>
</blockquote>
<br></span>
Can you please explain what is happening? It sounds like a bug we
should fix.<span><br>
<br></span></div></blockquote></span><div>I don't think it is LLVM bug but I am missing some thing or I have not implemented something related properly.</div><div>But I will experiment it with and let you my findings.</div><span class="gmail-"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div bgcolor="#FFFFFF"><span>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>What is ideal place where I can convert unordered
comparison to un comparison + OR + ordered comparison ?</div>
<div>Can I do it by adding required SDNodes ?</div>
<div>for example I am trying to do it in LowerBR_CC as shown
below:</div>
<div>
<div> getFPCCtoMBCC(CC,TCC);</div>
<div> TargetCC = DAG.getConstant(TCC, dl, MVT::i8);</div>
<div> Flag = DAG.getNode(XXXISD::FCMP, dl, MVT::Glue,
LHS, RHS,</div>
<div> TargetCC);</div>
<div> if (isUnordered) {</div>
<div> TCC = XXX::COND_UN;</div>
<div> TargetCC = DAG.getConstant(TCC, dl, MVT::i8);</div>
<div> SDValue UnComp = DAG.getNode(XXX::FCMP, dl,
MVT::Glue, LHS, RHS,</div>
<div> TargetCC);</div>
<div> Flag = DAG.getNode(ISD::OR, dl, MVT::Glue, Flag,
UnComp);</div>
<div> }</div>
</div>
<div>but here I can't OR 2 MVT::Glue value.</div>
<div>How can I compare results of two fcmp SDValue objs?</div>
</div>
</blockquote>
<br></span>
If your FCMP node sets some register, you'd need to read it
(DAG.getCopyFromReg).</div></blockquote></span></div></div></div></blockquote><div>Hey Hal,</div><div>I have few questions here,</div><div>Do you here mean FCMP sets any physical register ? Because as per my understanding getCopyFromReg() requires a reg operand to copy from. </div><div>What if it set some virtual register? Then how to use getCopyFromReg() method?</div><div><br></div><div>getCopyFromReg() requires a Chain operand so I have to make FCMP both Chain and Glue (by using <a class="gmail-code" href="http://llvm.org/docs/doxygen/html/structllvm_1_1SDVTList.html" title="This represents a list of ValueType's that has been intern'd by a SelectionDAG." style="font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253);color:rgb(70,101,162);text-decoration:none">SDVTList</a><span style="color:rgb(0,0,0);font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253)"> VTs = </span><a class="gmail-code" href="http://llvm.org/docs/doxygen/html/classllvm_1_1SelectionDAG.html#a196c23d6cb4d768d037970f1f35bbf66" title="Return an SDVTList that represents the list of values specified." style="font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253);color:rgb(70,101,162);text-decoration:none">getVTList</a><span style="color:rgb(0,0,0);font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253)">(</span><a class="gmail-code" href="http://llvm.org/docs/doxygen/html/classllvm_1_1MVT.html#afd69b4f2dff97a2d7c0192cc769ef50ca62a222acce6360abd2726719fabc2797" style="font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253);color:rgb(70,101,162);text-decoration:none">MVT::Other</a><span style="color:rgb(0,0,0);font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253)">, </span><a class="gmail-code" href="http://llvm.org/docs/doxygen/html/classllvm_1_1MVT.html#afd69b4f2dff97a2d7c0192cc769ef50ca59a1908cf136662bcfdc11ed49515ca9" style="font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253);color:rgb(70,101,162);text-decoration:none">MVT::Glue</a><span style="color:rgb(0,0,0);font-family:monospace,fixed;font-size:9pt;background-color:rgb(251,252,253)">))</span> right ?</div><div><br></div><div>Sincerely,</div><div>Vivek</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Ok I will see some examples for getCopyFromReg().</div><div><br></div><div>Thanks,</div><div>Vivek </div><div><div class="gmail-h5"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div bgcolor="#FFFFFF"><span class="gmail-m_-893470938952784482HOEnZb"><font color="#888888"><br>
<br>
-Hal</font></span><div><div class="gmail-m_-893470938952784482h5"><br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>Please provide some guidance.</div>
<div><br>
</div>
<div>Sincerely,</div>
<div>Vivek</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Mar 9, 2017 at 10:29 PM, vivek
pandya <span dir="ltr"><<a href="mailto:vivekvpandya@gmail.com" target="_blank">vivekvpandya@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">
<div>
<div class="gmail-m_-893470938952784482m_4013586522218816313h5">On Thu, Mar 9, 2017 at 9:35 PM, Hal
Finkel <span dir="ltr"><<a href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF">
<div>
<div class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101h5">
<p><br>
</p>
<div class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072moz-cite-prefix">On
02/25/2017 03:06 AM, vivek pandya via
llvm-dev wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Note: Question is written after
describing what I have coded.<br>
</div>
<div><br>
</div>
<div>Hello LLVMDevs,</div>
<div><br>
</div>
<div>I am trying to impliment floating
point comparsion for an architecture
which</div>
<div>supports following type of
floating point comparision if FPU is
available:</div>
<div>fcmp.un --> true if one of the
operand is NaN</div>
<div><a href="http://fcmp.lt" target="_blank">fcmp.lt</a> -->
ordered less than, if any input NaN
then return false</div>
<div>fcmp.eq --> ordered equal, if
any input NaN then return false</div>
<div>fcmp.le --> ordered less
equal, if any input NaN then return
false</div>
<div><a href="http://fcmp.gt" target="_blank">fcmp.gt</a> -->
ordered grater than, if any input
NaN then return false</div>
<div><a href="http://fcmp.ne" target="_blank">fcmp.ne</a> -->
ordered not equal, if any input NaN
then return true</div>
<div><a href="http://fcmp.ge" target="_blank">fcmp.ge</a> -->
ordered grater equal, if any input
NaN then return false</div>
<div><br>
</div>
<div>When FPU is not present I need to
generate a library call,</div>
<div><br>
</div>
<div>so I have added following code in
LowerBR_CC function in
XXXISelLowering.cpp</div>
<div><br>
</div>
<div>const XXXSubtarget &STI =
static_cast<const
XXXSubtarget&></div>
<div>
(DAG.getSubtarget());</div>
<div> XXXCC::CondCodes TCC;</div>
<div> getFPCCtoXXCC(CC,TCC);</div>
<div> TargetCC = DAG.getConstant(TCC,
dl, MVT::i8);</div>
<div> if (STI.useHardFloat()) {</div>
<div> // if fcmp instruction is
available use it</div>
<div> SDValue Flag =
DAG.getNode(XXXISD::FCMP, dl,
MVT::Glue, LHS, RHS,</div>
<div> TargetCC);</div>
<div> return
DAG.getNode(XXXISD::BR_CC, dl,
Op.getValueType(),</div>
<div> Chain, Dest,
TargetCC, Flag);</div>
<div> }</div>
<div> else {</div>
<div> // else generate library call</div>
<div> DAG.getTargetLoweringInfo().s<wbr>oftenSetCCOperands(DAG,
MVT::f32, LHS, RHS,</div>
<div>
CC, dl);</div>
<div><br>
</div>
<div> SDValue Flag =
DAG.getNode(XXXISD::CMP, dl,
MVT::Glue, LHS, RHS);</div>
<div><br>
</div>
<div> if (!RHS.getNode()) {</div>
<div> RHS = DAG.getConstant(0, dl,
LHS.getValueType());</div>
<div> TargetCC =
DAG.getConstant(XXXCC::COND_NE<wbr>,
dl, MVT::i8);</div>
<div> }</div>
<div> return
DAG.getNode(XXXISD::BR_CC, dl,
MVT::Other,</div>
<div> Chain, Dest,
TargetCC, Flag);</div>
<div> }</div>
<div><br>
</div>
<div> and code for getFPCCtoXXCC() is
as following:</div>
<div><br>
</div>
<div> static void
getFPCCtoXXCC(ISD::CondCode CC,
XXXCC::CondCodes &CondCode) {</div>
<div> switch (CC) {</div>
<div> default:</div>
<div> llvm_unreachable("Unknown
FP condition!");</div>
<div> case ISD::SETEQ:</div>
<div> case ISD::SETOEQ:</div>
<div> CondCode = XXXCC::COND_E;</div>
<div> break;</div>
<div> case ISD::SETGT:</div>
<div> case ISD::SETOGT:</div>
<div> CondCode = XXXCC::COND_GT;</div>
<div> break;</div>
<div> case ISD::SETGE:</div>
<div> case ISD::SETOGE:</div>
<div> CondCode = XXXCC::COND_GE;</div>
<div> break;</div>
<div> case ISD::SETOLT:</div>
<div> case ISD::SETLT:</div>
<div> CondCode = XXXCC::COND_LT;</div>
<div> break;</div>
<div> case ISD::SETOLE:</div>
<div> case ISD::SETLE:</div>
<div> CondCode = XXXCC::COND_LE;</div>
<div> break;</div>
<div> case ISD::SETONE:</div>
<div> case ISD::SETNE:</div>
<div> CondCode = XXXCC::COND_NE;</div>
<div> break;</div>
<div> case ISD::SETUO:</div>
<div> CondCode = XXXCC::COND_UN;</div>
<div> break;</div>
<div> case ISD::SETO:</div>
<div> case ISD::SETUEQ:</div>
<div> case ISD::SETUGT:</div>
<div> case ISD::SETUGE:</div>
<div> case ISD::SETULT:</div>
<div> case ISD::SETULE:</div>
<div> case ISD::SETUNE:</div>
<div> CC =
getSetCCInverse(CC,false);</div>
<div> getFPCCtoMBCC(CC,CondCode);</div>
<div> break;</div>
<div> }</div>
<div>}</div>
<div><br>
</div>
<div> I am generating wrong code when
using floating point library call
for </div>
<div>comparions. For the following
simple case:</div>
<div>float branchTest(float a, float
b) {</div>
<div><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>float
retVal;<span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span></div>
<div><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>if
(a == b) {<span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span></div>
<div><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>retVal
= a / b + 22.34;</div>
<div><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>}</div>
<div><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>return
retVal;</div>
<div>}</div>
<div>I am getting:</div>
<div>brlid<span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>r15,__nesf2</div>
<div>nop</div>
<div>beqi<span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>r3,.LBB0_2
; r3 is return regsiter</div>
<div><br>
</div>
<div>Now I want to understand
difference between three different
version of Condition</div>
<div>Codes for same operation and how
according to my target I should
handle them.</div>
<div>For example let's consider SETNE,
SETONE and SETUNE so for my
architecture </div>
<div>I think for floating point all
three are same</div>
</div>
</blockquote>
<br>
</div>
</div>
No, they're not the same. Please see:<br>
<br>
<a class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072moz-txt-link-freetext" href="http://llvm.org/docs/LangRef.html#id290" target="_blank">http://llvm.org/docs/LangRef.h<wbr>tml#id290</a><br>
<br>
which explains the difference between SETONE
(one) and SETUNE (une). Regarding how SETNE is
interpreted for FP, see the comment in the
definition of CondCode in
include/llvm/CodeGen/ISDOpcode<wbr>s.h which
explains, "// Don't care operations: undefined
if the input is a nan.".<br>
<br>
To support the unordered comparisons, if your
FPU has only ordered comparisons, then you
might need to do the underlying comparison,
and a NaN check, and then OR the results. I
think that using setCondCodeAction will cause
the expansions for the hardware-unsupported
variants to happen for you.<br>
<br>
-Hal<br>
</div>
</blockquote>
<div> </div>
</div>
</div>
<div>Thanks Hal for the guidance !</div>
<span class="gmail-m_-893470938952784482m_4013586522218816313HOEnZb"><font color="#888888">
<div><br>
</div>
<div>-Vivek </div>
</font></span>
<div>
<div class="gmail-m_-893470938952784482m_4013586522218816313h5">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF"> <br>
<blockquote type="cite"><span>
<div dir="ltr">
<div> so do I need to use </div>
<div>getSetCCInverse() ? Also when I
look at the code of </div>
<div>TargetLowering::softenSetCCOpe<wbr>rands
I see that for some condition code it
uses</div>
<div>getSetCCInverse() and also I am not
able to understand the way it groups </div>
<div>condition code in switch case for
example :</div>
<div> case ISD::SETEQ:</div>
<div> case ISD::SETOEQ:</div>
<div> LC1 = (VT == MVT::f32) ?
RTLIB::OEQ_F32 :</div>
<div> (VT == MVT::f64) ?
RTLIB::OEQ_F64 : RTLIB::OEQ_F128;</div>
<div> break;</div>
<div> case ISD::SETNE:</div>
<div> case ISD::SETUNE:</div>
<div> LC1 = (VT == MVT::f32) ?
RTLIB::UNE_F32 :</div>
<div> (VT == MVT::f64) ?
RTLIB::UNE_F64 : RTLIB::UNE_F128;</div>
<div> break;</div>
<div>here why SETNE and SETUNE is
considered same, why SETONE is
considered </div>
<div>differently. Is there any guideline
to lower conditional code properly?</div>
<div><br>
</div>
<div>Sincerely,</div>
<div>Vivek</div>
<div><br>
</div>
</div>
<br>
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<br>
</span>
<pre>______________________________<wbr>_________________
LLVM Developers mailing list
<a class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072moz-txt-link-abbreviated" href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>
<a class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072moz-txt-link-freetext" href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-dev</a><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101HOEnZb"><font color="#888888">
</font></span></pre><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101HOEnZb"><font color="#888888">
</font></span></blockquote><span class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101HOEnZb"><font color="#888888">
<pre class="gmail-m_-893470938952784482m_4013586522218816313m_7239601225858991101m_-2662977842983796072moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
</font></span></div>
</blockquote></div></div></div>
</div></div>
</blockquote></div>
</div>
</blockquote>
<pre class="gmail-m_-893470938952784482m_4013586522218816313moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre></div></div></div></blockquote></div></div></div><br></div></div>
</blockquote></div><br></div></div>