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path: root/test/Transforms/LoopRotate/phi-duplicate.ll
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2012-12-30Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ↵Dmitri Gribenko
ModuleID This is done to avoid odd test failures, like the one fixed in r171243. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171246 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08When loop rotation happens, it is *very* common for the duplicated condbrChris Lattner
to be foldable into an uncond branch. When this happens, we can make a much simpler CFG for the loop, which is important for nested loop cases where we want the outer loop to be aggressively optimized. Handle this case more aggressively. For example, previously on phi-duplicate.ll we would get this: define void @test(i32 %N, double* %G) nounwind ssp { entry: %cmp1 = icmp slt i64 1, 1000 br i1 %cmp1, label %bb.nph, label %for.end bb.nph: ; preds = %entry br label %for.body for.body: ; preds = %bb.nph, %for.cond %j.02 = phi i64 [ 1, %bb.nph ], [ %inc, %for.cond ] %arrayidx = getelementptr inbounds double* %G, i64 %j.02 %tmp3 = load double* %arrayidx %sub = sub i64 %j.02, 1 %arrayidx6 = getelementptr inbounds double* %G, i64 %sub %tmp7 = load double* %arrayidx6 %add = fadd double %tmp3, %tmp7 %arrayidx10 = getelementptr inbounds double* %G, i64 %j.02 store double %add, double* %arrayidx10 %inc = add nsw i64 %j.02, 1 br label %for.cond for.cond: ; preds = %for.body %cmp = icmp slt i64 %inc, 1000 br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge for.cond.for.end_crit_edge: ; preds = %for.cond br label %for.end for.end: ; preds = %for.cond.for.end_crit_edge, %entry ret void } Now we get the much nicer: define void @test(i32 %N, double* %G) nounwind ssp { entry: br label %for.body for.body: ; preds = %entry, %for.body %j.01 = phi i64 [ 1, %entry ], [ %inc, %for.body ] %arrayidx = getelementptr inbounds double* %G, i64 %j.01 %tmp3 = load double* %arrayidx %sub = sub i64 %j.01, 1 %arrayidx6 = getelementptr inbounds double* %G, i64 %sub %tmp7 = load double* %arrayidx6 %add = fadd double %tmp3, %tmp7 %arrayidx10 = getelementptr inbounds double* %G, i64 %j.01 store double %add, double* %arrayidx10 %inc = add nsw i64 %j.01, 1 %cmp = icmp slt i64 %inc, 1000 br i1 %cmp, label %for.body, label %for.end for.end: ; preds = %for.body ret void } With all of these recent changes, we are now able to compile: void foo(char *X) { for (int i = 0; i != 100; ++i) for (int j = 0; j != 100; ++j) X[j+i*100] = 0; } into a single memset of 10000 bytes. This series of changes should also be helpful for other nested loop scenarios as well. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123079 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Three major changes:Chris Lattner
1. Rip out LoopRotate's domfrontier updating code. It isn't needed now that LICM doesn't use DF and it is super complex and gross. 2. Make DomTree updating code a lot simpler and faster. The old loop over all the blocks was just to find a block?? 3. Change the code that inserts the new preheader to just use SplitCriticalEdge instead of doing an overcomplex reimplementation of it. No behavior change, except for the name of the inserted preheader. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123072 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08Have loop-rotate simplify instructions (yay instsimplify!) as it clonesChris Lattner
them into the loop preheader, eliminating silly instructions like "icmp i32 0, 100" in fixed tripcount loops. This also better exposes the bigger problem with loop rotate that I'd like to fix: once this has been folded, the duplicated conditional branch *often* turns into an uncond branch. Not aggressively handling this is pessimizing later loop optimizations somethin' fierce by making "dominates all exit blocks" checks fail. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123060 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17When rotating loops, put the original header at the bottom of theDan Gohman
loop, making the resulting loop significantly less ugly. Also, zap its trivial PHI nodes, since it's easy. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111255 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-26Fix some tests that didn't test anything.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106954 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-21fix PR5837 by having SSAUpdate reuse phi nodes for theChris Lattner
'GetValueInMiddleOfBlock' case, instead of inserting duplicates. A similar fix is almost certainly needed by the machine-level SSAUpdate implementation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91820 91177308-0d34-0410-b5e6-96231b3b80d8