<div dir="ltr">Hi Chad,<div><br></div><div>On cortex-a57, we found a 3.8% performance regression on 429.mcf in spec2006 due to this commit, would you have a look of this?</div><div><br></div><div>The branch order changed by this commit.</div><div><br></div><div>Before:</div><div><div> tbz<span class="" style="white-space:pre"> </span>x8, #63, 4028e0 <primal_bea_mpp+0x250></div><div> cmp<span class="" style="white-space:pre"> </span>w12, #0x1</div><div> b.eq<span class="" style="white-space:pre"> </span>4028ec <primal_bea_mpp+0x25c></div></div><div><br></div><div><br></div><div>After:</div><div><div> cmp<span class="" style="white-space:pre"> </span>w12, #0x1</div><div> <a href="http://b.ne">b.ne</a><span class="" style="white-space:pre"> </span>40290c <primal_bea_mpp+0x250></div><div> tbnz<span class="" style="white-space:pre"> </span>x8, #63, 402918 <primal_bea_mpp+0x25c></div></div><div><br></div><div>This change happens in function primal_bea_mpp and got performance worse.</div><div><br></div><div>I didn't look into detail, that's all what I know from a simple investigation. Hopefully this can give you a clue to fix it.</div><div><br></div><div>Thanks,</div><div>Kevin </div></div><div class="gmail_extra"><br><div class="gmail_quote">2014-11-14 17:09 GMT+00:00 Chad Rosier <span dir="ltr"><<a href="mailto:mcrosier@codeaurora.org" target="_blank">mcrosier@codeaurora.org</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: mcrosier<br>
Date: Fri Nov 14 11:09:19 2014<br>
New Revision: 222008<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=222008&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=222008&view=rev</a><br>
Log:<br>
[Reassociate] Canonicalize the operands of all binary operators.<br>
<br>
Added:<br>
llvm/trunk/test/Transforms/Reassociate/commute.ll<br>
Modified:<br>
llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp<br>
llvm/trunk/test/Transforms/Reassociate/multistep.ll<br>
<br>
Modified: llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp?rev=222008&r1=222007&r2=222008&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp?rev=222008&r1=222007&r2=222008&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp (original)<br>
+++ llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp Fri Nov 14 11:09:19 2014<br>
@@ -2078,19 +2078,19 @@ void Reassociate::OptimizeInst(Instructi<br>
if (Instruction *Res = canonicalizeNegConstExpr(I))<br>
I = Res;<br>
<br>
- // Commute floating point binary operators, to canonicalize the order of their<br>
- // operands. This can potentially expose more CSE opportunities, and makes<br>
- // writing other transformations simpler.<br>
- if (I->getType()->isFloatingPointTy() || I->getType()->isVectorTy()) {<br>
+ // Commute binary operators, to canonicalize the order of their operands.<br>
+ // This can potentially expose more CSE opportunities, and makes writing other<br>
+ // transformations simpler.<br>
+ if (I->isCommutative())<br>
+ canonicalizeOperands(I);<br>
<br>
- if (I->isCommutative())<br>
- canonicalizeOperands(I);<br>
+ // Don't optimize vector instructions.<br>
+ if (I->getType()->isVectorTy())<br>
+ return;<br>
<br>
- // Don't try to optimize vector instructions or anything that doesn't have<br>
- // unsafe algebra.<br>
- if (I->getType()->isVectorTy() || !I->hasUnsafeAlgebra())<br>
- return;<br>
- }<br>
+ // Don't optimize floating point instructions that don't have unsafe algebra.<br>
+ if (I->getType()->isFloatingPointTy() && !I->hasUnsafeAlgebra())<br>
+ return;<br>
<br>
// Do not reassociate boolean (i1) expressions. We want to preserve the<br>
// original order of evaluation for short-circuited comparisons that<br>
<br>
Added: llvm/trunk/test/Transforms/Reassociate/commute.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Reassociate/commute.ll?rev=222008&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Reassociate/commute.ll?rev=222008&view=auto</a><br>
==============================================================================<br>
--- llvm/trunk/test/Transforms/Reassociate/commute.ll (added)<br>
+++ llvm/trunk/test/Transforms/Reassociate/commute.ll Fri Nov 14 11:09:19 2014<br>
@@ -0,0 +1,19 @@<br>
+; RUN: opt -reassociate -S < %s | FileCheck %s<br>
+<br>
+declare void @use(i32)<br>
+<br>
+define void @test1(i32 %x, i32 %y) {<br>
+; CHECK-LABEL: test1<br>
+; CHECK: mul i32 %y, %x<br>
+; CHECK: mul i32 %y, %x<br>
+; CHECK: sub i32 %1, %2<br>
+; CHECK: call void @use(i32 %{{.*}})<br>
+; CHECK: call void @use(i32 %{{.*}})<br>
+<br>
+ %1 = mul i32 %x, %y<br>
+ %2 = mul i32 %y, %x<br>
+ %3 = sub i32 %1, %2<br>
+ call void @use(i32 %1)<br>
+ call void @use(i32 %3)<br>
+ ret void<br>
+}<br>
<br>
Modified: llvm/trunk/test/Transforms/Reassociate/multistep.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Reassociate/multistep.ll?rev=222008&r1=222007&r2=222008&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Reassociate/multistep.ll?rev=222008&r1=222007&r2=222008&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/test/Transforms/Reassociate/multistep.ll (original)<br>
+++ llvm/trunk/test/Transforms/Reassociate/multistep.ll Fri Nov 14 11:09:19 2014<br>
@@ -9,7 +9,7 @@ define i64 @multistep1(i64 %a, i64 %b, i<br>
%t3 = mul i64 %a, %t2 ; a*(a*c)<br>
%t4 = add i64 %t1, %t3<br>
; CHECK-NEXT: add i64 %c, %b<br>
-; CHECK-NEXT: mul i64 %tmp{{.*}}, %a<br>
+; CHECK-NEXT: mul i64 %a, %tmp{{.*}}<br>
; CHECK-NEXT: mul i64 %tmp{{.*}}, %a<br>
; CHECK-NEXT: ret<br>
ret i64 %t4<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr">Best Regards,<div><br></div><div>Kevin Qin</div></div></div>
</div>