[llvm-commits] [llvm] r167045 - in /llvm/trunk: lib/Transforms/Scalar/LoopIdiomRecognize.cpp test/Transforms/LoopIdiom/memmove.ll
Benjamin Kramer
benny.kra at googlemail.com
Tue Oct 30 12:49:39 PDT 2012
Author: d0k
Date: Tue Oct 30 14:49:39 2012
New Revision: 167045
URL: http://llvm.org/viewvc/llvm-project?rev=167045&view=rev
Log:
LoopIdiom: Fix a serious missed optimization: we only turned top-level loops into memmove.
Thanks to Preston Briggs for catching this!
Added:
llvm/trunk/test/Transforms/LoopIdiom/memmove.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp?rev=167045&r1=167044&r2=167045&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp Tue Oct 30 14:49:39 2012
@@ -555,10 +555,11 @@
// can safely emit a memcpy.
OwningPtr<Dependence> Dep(DA.depends(SI, LI, true));
if (Dep) {
- // If there is a dependence but the direction is positive we can still
- // safely turn this into memmove.
- if (Dep->getLevels() != 1 ||
- Dep->getDirection(1) != Dependence::DVEntry::GT)
+ // If there is a dependence but the direction is positive (or none) we can
+ // still safely turn this into memmove.
+ unsigned Direction = Dep->getDirection(Dep->getLevels());
+ if (Direction != Dependence::DVEntry::NONE &&
+ Direction != Dependence::DVEntry::GT)
return false;
isMemcpySafe = false;
}
Added: llvm/trunk/test/Transforms/LoopIdiom/memmove.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopIdiom/memmove.ll?rev=167045&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopIdiom/memmove.ll (added)
+++ llvm/trunk/test/Transforms/LoopIdiom/memmove.ll Tue Oct 30 14:49:39 2012
@@ -0,0 +1,42 @@
+; RUN: opt -S -basicaa -loop-idiom < %s | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+declare i64 @foo() nounwind
+
+; Nested loops
+define void @test1(i8* nocapture %A, i64 %n) nounwind {
+entry:
+ %call8 = tail call i64 @foo() nounwind
+ %tobool9 = icmp eq i64 %call8, 0
+ br i1 %tobool9, label %while.end, label %for.cond.preheader.lr.ph
+
+for.cond.preheader.lr.ph: ; preds = %entry
+ %cmp6 = icmp eq i64 %n, 0
+ br label %for.cond.preheader
+
+while.cond.loopexit: ; preds = %for.body, %for.cond.preheader
+ %call = tail call i64 @foo() nounwind
+ %tobool = icmp eq i64 %call, 0
+ br i1 %tobool, label %while.end, label %for.cond.preheader
+
+for.cond.preheader: ; preds = %for.cond.preheader.lr.ph, %while.cond.loopexit
+ br i1 %cmp6, label %while.cond.loopexit, label %for.body
+
+for.body: ; preds = %for.cond.preheader, %for.body
+ %i.07 = phi i64 [ %inc, %for.body ], [ 0, %for.cond.preheader ]
+ %add = add i64 %i.07, 10
+ %arrayidx = getelementptr inbounds i8* %A, i64 %add
+ %0 = load i8* %arrayidx, align 1
+ %arrayidx1 = getelementptr inbounds i8* %A, i64 %i.07
+ store i8 %0, i8* %arrayidx1, align 1
+ %inc = add i64 %i.07, 1
+ %exitcond = icmp eq i64 %inc, %n
+ br i1 %exitcond, label %while.cond.loopexit, label %for.body
+
+while.end: ; preds = %while.cond.loopexit, %entry
+ ret void
+
+; CHECK: @test1
+; CHECK: call void @llvm.memmove.p0i8.p0i8.i64(
+}
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