[llvm] r363165 - LoopVersioning: Respect convergent

[Michael Kruse via llvm-commits]

Could add a

Differential Revision: https://reviews.llvm.org/D63016

to the commit message when landing a patch? Thank you.

Michael



Am Mi., 12. Juni 2019 um 09:02 Uhr schrieb Matt Arsenault via
llvm-commits <llvm-commits at lists.llvm.org>:
>
> Author: arsenm
> Date: Wed Jun 12 07:05:58 2019
> New Revision: 363165
>
> URL: http://llvm.org/viewvc/llvm-project?rev=363165&view=rev
> Log:
> LoopVersioning: Respect convergent
>
> This changes the standalone pass only. Arguably the utility class
> itself should assert there are no convergent calls. However, a target
> pass with additional context may still be able to version a loop if
> all of the dynamic conditions are sufficiently uniform.
>
> Added:
>     llvm/trunk/test/Transforms/LoopVersioning/convergent.ll
> Modified:
>     llvm/trunk/lib/Transforms/Utils/LoopVersioning.cpp
>
> Modified: llvm/trunk/lib/Transforms/Utils/LoopVersioning.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopVersioning.cpp?rev=363165&r1=363164&r2=363165&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/LoopVersioning.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/LoopVersioning.cpp Wed Jun 12 07:05:58 2019
> @@ -280,8 +280,9 @@ public:
>      bool Changed = false;
>      for (Loop *L : Worklist) {
>        const LoopAccessInfo &LAI = LAA->getInfo(L);
> -      if (L->isLoopSimplifyForm() && (LAI.getNumRuntimePointerChecks() ||
> -          !LAI.getPSE().getUnionPredicate().isAlwaysTrue())) {
> +      if (L->isLoopSimplifyForm() && !LAI.hasConvergentOp() &&
> +          (LAI.getNumRuntimePointerChecks() ||
> +           !LAI.getPSE().getUnionPredicate().isAlwaysTrue())) {
>          LoopVersioning LVer(LAI, L, LI, DT, SE);
>          LVer.versionLoop();
>          LVer.annotateLoopWithNoAlias();
>
> Added: llvm/trunk/test/Transforms/LoopVersioning/convergent.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVersioning/convergent.ll?rev=363165&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopVersioning/convergent.ll (added)
> +++ llvm/trunk/test/Transforms/LoopVersioning/convergent.ll Wed Jun 12 07:05:58 2019
> @@ -0,0 +1,40 @@
> +; RUN: opt -basicaa -loop-versioning -S < %s | FileCheck %s
> +
> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
> +
> +; Do not version this loop because of a convergent operation
> +
> +; CHECK-LABEL: @f(
> +; CHECK: call i32 @llvm.convergent(
> +; CHECK-NOT: call i32 @llvm.convergent(
> +define void @f(i32* %a, i32* %b, i32* %c) #0 {
> +entry:
> +  br label %for.body
> +
> +for.body:                                         ; preds = %for.body, %entry
> +  %ind = phi i64 [ 0, %entry ], [ %add, %for.body ]
> +
> +  %arrayidxA = getelementptr inbounds i32, i32* %a, i64 %ind
> +  %loadA = load i32, i32* %arrayidxA, align 4
> +
> +  %arrayidxB = getelementptr inbounds i32, i32* %b, i64 %ind
> +  %loadB = load i32, i32* %arrayidxB, align 4
> +  %convergentB = call i32 @llvm.convergent(i32 %loadB)
> +
> +  %mulC = mul i32 %loadA, %convergentB
> +
> +  %arrayidxC = getelementptr inbounds i32, i32* %c, i64 %ind
> +  store i32 %mulC, i32* %arrayidxC, align 4
> +
> +  %add = add nuw nsw i64 %ind, 1
> +  %exitcond = icmp eq i64 %add, 20
> +  br i1 %exitcond, label %for.end, label %for.body
> +
> +for.end:                                          ; preds = %for.body
> +  ret void
> +}
> +
> +declare i32 @llvm.convergent(i32) #1
> +
> +attributes #0 = { nounwind convergent }
> +attributes #1 = { nounwind readnone convergent }
>
>
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