<div dir="ltr">Sorry for the noise. Must have been due to the recent email issues.</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, May 16, 2014 at 5:32 PM, David Majnemer <span dir="ltr"><<a href="mailto:david.majnemer@gmail.com" target="_blank">david.majnemer@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">Yes, Nick LGTM'd this. See <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140512/217399.html" target="_blank">http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140512/217399.html</a> for details.</div>
<div class="HOEnZb"><div class="h5">
<div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, May 16, 2014 at 4:08 PM, Sean Silva <span dir="ltr"><<a href="mailto:chisophugis@gmail.com" target="_blank">chisophugis@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">Did Nick ever LGTM this? The phab revision seems to not have had any movement.<span><font color="#888888"><div>
<br></div><div>-- Sean Silva</div></font></span></div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, May 14, 2014 at 6:02 PM, David Majnemer <span dir="ltr"><<a href="mailto:david.majnemer@gmail.com" target="_blank">david.majnemer@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: majnemer<br>
Date: Wed May 14 19:02:20 2014<br>
New Revision: 208827<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=208827&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=208827&view=rev</a><br>
Log:<br>
InstCombine: Optimize -x s< cst<br>
<br>
Summary:<br>
This gets rid of a sub instruction by moving the negation to the<br>
constant when valid.<br>
<br>
Reviewers: nicholas<br>
<br>
Subscribers: llvm-commits<br>
<br>
Differential Revision: <a href="http://reviews.llvm.org/D3773" target="_blank">http://reviews.llvm.org/D3773</a><br>
<br>
Modified:<br>
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp<br>
llvm/trunk/test/Transforms/InstCombine/icmp.ll<br>
<br>
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=208827&r1=208826&r2=208827&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=208827&r1=208826&r2=208827&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)<br>
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Wed May 14 19:02:20 2014<br>
@@ -2971,6 +2971,16 @@ Instruction *InstCombiner::visitICmpInst<br>
BO0->hasOneUse() && BO1->hasOneUse())<br>
return new ICmpInst(Pred, D, B);<br>
<br>
+ // icmp (0-X) < cst --> x > -cst<br>
+ if (NoOp0WrapProblem && ICmpInst::isSigned(Pred)) {<br>
+ Value *X;<br>
+ if (match(BO0, m_Neg(m_Value(X))))<br>
+ if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1))<br>
+ if (!RHSC->isMinValue(/*isSigned=*/true))<br>
+ return new ICmpInst(I.getSwappedPredicate(), X,<br>
+ ConstantExpr::getNeg(RHSC));<br>
+ }<br>
+<br>
BinaryOperator *SRem = nullptr;<br>
// icmp (srem X, Y), Y<br>
if (BO0 && BO0->getOpcode() == Instruction::SRem &&<br>
<br>
Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=208827&r1=208826&r2=208827&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=208827&r1=208826&r2=208827&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)<br>
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Wed May 14 19:02:20 2014<br>
@@ -1356,3 +1356,12 @@ define i1 @icmp_ashr_ashr_ne(i32 %a, i32<br>
%z = icmp ne i32 %x, %y<br>
ret i1 %z<br>
}<br>
+<br>
+; CHECK-LABEL: @icmp_neg_cst_slt<br>
+; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp sgt i32 %a, 10<br>
+; CHECK-NEXT: ret i1 [[CMP]]<br>
+define i1 @icmp_neg_cst_slt(i32 %a) {<br>
+ %1 = sub nsw i32 0, %a<br>
+ %2 = icmp slt i32 %1, -10<br>
+ ret i1 %2<br>
+}<br>
<br>
<br>
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