<div dir="ltr">Can we remove the subsequent call to <span style="font-size:12.8000001907349px">createInstructionSimplifierPas</span><span style="font-size:12.8000001907349px">s? InstCombine should be strictly more powerful.</span></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, May 14, 2015 at 3:02 PM, Wei Mi <span dir="ltr"><<a href="mailto:wmi@google.com" target="_blank">wmi@google.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: wmi<br>
Date: Thu May 14 17:02:54 2015<br>
New Revision: 237395<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=237395&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=237395&view=rev</a><br>
Log:<br>
Add another InstCombine pass after LoopUnroll.<br>
<br>
This is to cleanup some redundency generated by LoopUnroll pass. Such redundency may not be cleaned up by existing passes after LoopUnroll.<br>
<br>
Differential Revision: <a href="http://reviews.llvm.org/D9777" target="_blank">http://reviews.llvm.org/D9777</a><br>
<br>
Added:<br>
llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll<br>
Modified:<br>
llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp<br>
<br>
Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=237395&r1=237394&r2=237395&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=237395&r1=237394&r2=237395&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)<br>
+++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu May 14 17:02:54 2015<br>
@@ -382,6 +382,9 @@ void PassManagerBuilder::populateModuleP<br>
if (!DisableUnrollLoops) {<br>
MPM.add(createLoopUnrollPass()); // Unroll small loops<br>
<br>
+ // LoopUnroll may generate some redundency to cleanup.<br>
+ MPM.add(createInstructionCombiningPass());<br>
+<br>
// This is a barrier pass to avoid combine LICM pass and loop unroll pass<br>
// within same loop pass manager.<br>
MPM.add(createInstructionSimplifierPass());<br>
<br>
Added: llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll?rev=237395&view=auto" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll?rev=237395&view=auto</a><br>
==============================================================================<br>
--- llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll (added)<br>
+++ llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll Thu May 14 17:02:54 2015<br>
@@ -0,0 +1,85 @@<br>
+; PR23524<br>
+; The test is to check redundency produced by loop unroll pass<br>
+; should be cleaned up by later pass.<br>
+; RUN: opt < %s -O2 -S | FileCheck %s<br>
+<br>
+; After loop unroll:<br>
+; %dec18 = add nsw i32 %<a href="http://dec18.in" target="_blank">dec18.in</a>, -1<br>
+; ...<br>
+; %dec18.1 = add nsw i32 %dec18, -1<br>
+; should be merged to:<br>
+; %dec18.1 = add nsw i32 %<a href="http://dec18.in" target="_blank">dec18.in</a>, -2<br>
+;<br>
+; CHECK-LABEL: @_Z3fn1v(<br>
+; CHECK: %dec18.1 = add nsw i32 %<a href="http://dec18.in" target="_blank">dec18.in</a>, -2<br>
+<br>
+; ModuleID = '<stdin>'<br>
+target triple = "x86_64-unknown-linux-gnu"<br>
+<br>
+@b = global i32 0, align 4<br>
+@c = global i32 0, align 4<br>
+<br>
+; Function Attrs: nounwind uwtable<br>
+define void @_Z3fn1v() #0 {<br>
+entry:<br>
+ %tmp = load i32, i32* @b, align 4<br>
+ %tobool20 = icmp eq i32 %tmp, 0<br>
+ br i1 %tobool20, label %for.end6, label %<a href="http://for.body.lr.ph" target="_blank">for.body.lr.ph</a><br>
+<br>
+<a href="http://for.body.lr.ph" target="_blank">for.body.lr.ph</a>: ; preds = %entry<br>
+ br label %for.body<br>
+<br>
+for.cond1.for.cond.loopexit_crit_edge: ; preds = %for.inc<br>
+ %add.ptr.lcssa = phi i16* [ %add.ptr, %for.inc ]<br>
+ %incdec.ptr.lcssa = phi i8* [ %incdec.ptr, %for.inc ]<br>
+ br label %for.cond.loopexit<br>
+<br>
+for.cond.loopexit: ; preds = %for.body, %for.cond1.for.cond.loopexit_crit_edge<br>
+ %r.1.lcssa = phi i16* [ %add.ptr.lcssa, %for.cond1.for.cond.loopexit_crit_edge ], [ %r.022, %for.body ]<br>
+ %a.1.lcssa = phi i8* [ %incdec.ptr.lcssa, %for.cond1.for.cond.loopexit_crit_edge ], [ %a.021, %for.body ]<br>
+ %tmp1 = load i32, i32* @b, align 4<br>
+ %tobool = icmp eq i32 %tmp1, 0<br>
+ br i1 %tobool, label %for.cond.for.end6_crit_edge, label %for.body<br>
+<br>
+for.body: ; preds = %for.cond.loopexit, %<a href="http://for.body.lr.ph" target="_blank">for.body.lr.ph</a><br>
+ %r.022 = phi i16* [ undef, %<a href="http://for.body.lr.ph" target="_blank">for.body.lr.ph</a> ], [ %r.1.lcssa, %for.cond.loopexit ]<br>
+ %a.021 = phi i8* [ undef, %<a href="http://for.body.lr.ph" target="_blank">for.body.lr.ph</a> ], [ %a.1.lcssa, %for.cond.loopexit ]<br>
+ %tmp2 = load i32, i32* @c, align 4<br>
+ %tobool215 = icmp eq i32 %tmp2, 0<br>
+ br i1 %tobool215, label %for.cond.loopexit, label %<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a><br>
+<br>
+<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a>: ; preds = %for.body<br>
+ br label %for.body3<br>
+<br>
+for.body3: ; preds = %for.inc, %<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a><br>
+ %<a href="http://dec18.in" target="_blank">dec18.in</a> = phi i32 [ %tmp2, %<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a> ], [ %dec18, %for.inc ]<br>
+ %r.117 = phi i16* [ %r.022, %<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a> ], [ %add.ptr, %for.inc ]<br>
+ %a.116 = phi i8* [ %a.021, %<a href="http://for.body3.lr.ph" target="_blank">for.body3.lr.ph</a> ], [ %incdec.ptr, %for.inc ]<br>
+ %dec18 = add nsw i32 %<a href="http://dec18.in" target="_blank">dec18.in</a>, -1<br>
+ %tmp3 = load i8, i8* %a.116, align 1<br>
+ %cmp = icmp eq i8 %tmp3, 0<br>
+ br i1 %cmp, label %if.then, label %for.inc<br>
+<br>
+if.then: ; preds = %for.body3<br>
+ %arrayidx = getelementptr inbounds i16, i16* %r.117, i64 1<br>
+ store i16 0, i16* %arrayidx, align 2<br>
+ store i16 0, i16* %r.117, align 2<br>
+ %arrayidx5 = getelementptr inbounds i16, i16* %r.117, i64 2<br>
+ store i16 0, i16* %arrayidx5, align 2<br>
+ br label %for.inc<br>
+<br>
+for.inc: ; preds = %if.then, %for.body3<br>
+ %incdec.ptr = getelementptr inbounds i8, i8* %a.116, i64 1<br>
+ %add.ptr = getelementptr inbounds i16, i16* %r.117, i64 3<br>
+ %tobool2 = icmp eq i32 %dec18, 0<br>
+ br i1 %tobool2, label %for.cond1.for.cond.loopexit_crit_edge, label %for.body3, !llvm.loop !0<br>
+<br>
+for.cond.for.end6_crit_edge: ; preds = %for.cond.loopexit<br>
+ br label %for.end6<br>
+<br>
+for.end6: ; preds = %for.cond.for.end6_crit_edge, %entry<br>
+ ret void<br>
+}<br>
+<br>
+!0 = !{!0, !1}<br>
+!1 = !{!"llvm.loop.unroll.count", i32 2}<br>
<br>
<br>
_______________________________________________<br>
llvm-commits mailing list<br>
<a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><br>
</blockquote></div><br></div>