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<div class="moz-cite-prefix">On 03/14/2017 07:16 AM, vivek pandya
wrote:<br>
</div>
<blockquote
cite="mid:CAHYgpoJBYB=inHJ7S1EwYz3b+hS99Li3ACVDXh4K1Qd2kryPmg@mail.gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<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>
Can you please explain what is happening? It sounds like a bug we
should fix.<br>
<br>
<blockquote
cite="mid:CAHYgpoJBYB=inHJ7S1EwYz3b+hS99Li3ACVDXh4K1Qd2kryPmg@mail.gmail.com"
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>
If your FCMP node sets some register, you'd need to read it
(DAG.getCopyFromReg).<br>
<br>
-Hal<br>
<br>
<blockquote
cite="mid:CAHYgpoJBYB=inHJ7S1EwYz3b+hS99Li3ACVDXh4K1Qd2kryPmg@mail.gmail.com"
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 moz-do-not-send="true"
href="mailto:vivekvpandya@gmail.com" target="_blank">vivekvpandya@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">
<div>
<div class="h5">On Thu, Mar 9, 2017 at 9:35 PM, Hal
Finkel <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>
<div class="m_7239601225858991101h5">
<p><br>
</p>
<div
class="m_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 moz-do-not-send="true"
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 moz-do-not-send="true"
href="http://fcmp.gt"
target="_blank">fcmp.gt</a> -->
ordered grater than, if any input
NaN then return false</div>
<div><a moz-do-not-send="true"
href="http://fcmp.ne"
target="_blank">fcmp.ne</a> -->
ordered not equal, if any input NaN
then return true</div>
<div><a moz-do-not-send="true"
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="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>float
retVal;<span class="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span></div>
<div><span class="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>if
(a == b) {<span class="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span></div>
<div><span class="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>retVal
= a / b + 22.34;</div>
<div><span class="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>}</div>
<div><span class="m_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="m_7239601225858991101m_-2662977842983796072gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>r15,__nesf2</div>
<div>nop</div>
<div>beqi<span class="m_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 moz-do-not-send="true"
class="m_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="HOEnZb"><font color="#888888">
<div><br>
</div>
<div>-Vivek </div>
</font></span>
<div>
<div class="h5">
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> <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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class="m_7239601225858991101m_-2662977842983796072mimeAttachmentHeader"></fieldset>
<br>
</span>
<pre>______________________________<wbr>_________________
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<a moz-do-not-send="true" class="m_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="m_7239601225858991101HOEnZb"><font color="#888888">
</font></span></pre><span class="m_7239601225858991101HOEnZb"><font color="#888888">
</font></span></blockquote><span class="m_7239601225858991101HOEnZb"><font color="#888888">
<pre class="m_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="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre></body></html>