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<p class="MsoNormal">Hi All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am trying to unroll the below loop, but couldn’t as SCEV returns TripCount as 0.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#4F81BD">void foo(int x) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> int p, i = 1;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> int mat[6][6][6];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> for (p = x+3 ; p<= x+6 ;p++)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> mat[x][p][i] = mat[x][p][i] + 5;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"><o:p> </o:p></span></p>
<p class="MsoNormal">For a quick reference I have added the generated IR compiled with clang using –O3.<o:p></o:p></p>
<p class="MsoNormal">Please let me know if this is an known issue in SCEV or I am missing something here ?<o:p></o:p></p>
<p class="MsoNormal"><span style="color:#4F81BD"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">; Function Attrs: nounwind readnone uwtable<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">define void @_Z3fooi(i32 %x) local_unnamed_addr #0 {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">entry:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %mat = alloca [6 x [6 x [6 x i32]]], align 16<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %0 = bitcast [6 x [6 x [6 x i32]]]* %mat to i8*<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> call void @llvm.lifetime.start(i64 864, i8* %0) #2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %add = add nsw i32 %x, 3<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %add1 = add nsw i32 %x, 6<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %idxprom3 = sext i32 %x to i64<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %1 = sext i32 %add to i64<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %2 = sext i32 %add1 to i64<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> br label %for.body<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">for.body: ; preds = %for.body, %entry<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ %1, %entry ]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %arrayidx5 = getelementptr inbounds [6 x [6 x [6 x i32]]], [6 x [6 x [6 x i32]]]* %mat, i64 0, i64 %idxprom3, i64 %indvars.iv, i64 1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %3 = load i32, i32* %arrayidx5, align 4, !tbaa !1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %add6 = add nsw i32 %3, 5<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> store i32 %add6, i32* %arrayidx5, align 4, !tbaa !1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %indvars.iv.next = add nsw i64 %indvars.iv, 1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> %cmp = icmp slt i64 %indvars.iv, %2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> br i1 %cmp, label %for.body, label %for.end<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">for.end: ; preds = %for.body<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> call void @llvm.lifetime.end(i64 864, i8* nonnull %0) #2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"> ret void<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD">} <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#4F81BD"><o:p> </o:p></span></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Deepali<o:p></o:p></p>
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