[PATCH] D106656: [LV] Remove assert that VF cannot be scalable in setCostBasedWideningDecision.

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen updated this revision to Diff 361185.
sdesmalen added a comment.

Removed loop attribute from the test, because that actually caused the test to not actually test the code-change.

That's because it would always choose a VF=vscale x 4, and would therefore never try to compute a widening decision for VF=vscale x 1, which causes this issue.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D106656/new/

https://reviews.llvm.org/D106656

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll


Index: llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
===================================================================
--- llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
+++ llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
@@ -122,6 +122,37 @@
   ret void
 }
 
+
+
+define void @gather_nxv4i32_ind64_stride2(float* noalias nocapture readonly %a, float* noalias nocapture readonly %b, i64 %n) {
+; CHECK-LABEL: @gather_nxv4i32_ind64_stride2
+; CHECK: vector.body:
+; CHECK:      %[[IDX:.*]] = phi i64 [ 0, %vector.ph ], [ %{{.*}}, %vector.body ]
+; CHECK-DAG:  %[[STEP:.*]] = call <vscale x 4 x i64> @llvm.experimental.stepvector.nxv4i64()
+; CHECK-DAG:  %[[IDXSPLATINS:.*]] = insertelement <vscale x 4 x i64> poison, i64 %index, i32 0
+; CHECK-DAG:  %[[IDXSPLAT:.*]] = shufflevector <vscale x 4 x i64> %[[IDXSPLATINS]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
+; CHECK:      %[[ADD:.*]] = add <vscale x 4 x i64> %[[IDXSPLAT]], %[[STEP]]
+; CHECK:      %[[MUL:.*]] = shl <vscale x 4 x i64> %[[ADD]], shufflevector (<vscale x 4 x i64> insertelement (<vscale x 4 x i64> undef, i64 1, i32 0), <vscale x 4 x i64> undef, <vscale x 4 x i32> zeroinitializer)
+; CHECK:      %[[PTRS:.*]] = getelementptr inbounds float, float* %b, <vscale x 4 x i64> %[[MUL]]
+; CHECK:      call <vscale x 4 x float> @llvm.masked.gather.nxv4f32.nxv4p0f32(<vscale x 4 x float*> %[[PTRS]]
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %entry, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+  %indvars.iv.stride2 = mul i64 %indvars.iv, 2
+  %arrayidx = getelementptr inbounds float, float* %b, i64 %indvars.iv.stride2
+  %0 = load float, float* %arrayidx, align 4
+  %arrayidx2 = getelementptr inbounds float, float* %a, i64 %indvars.iv
+  store float %0, float* %arrayidx2, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond.not = icmp eq i64 %indvars.iv.next, %n
+  br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
+  ret void
+}
+
 !0 = distinct !{!0, !1, !2, !3, !4, !5}
 !1 = !{!"llvm.loop.mustprogress"}
 !2 = !{!"llvm.loop.vectorize.width", i32 4}
Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -7413,8 +7413,6 @@
         Decision = CM_GatherScatter;
         Cost = GatherScatterCost;
       } else {
-        assert(!VF.isScalable() &&
-               "We cannot yet scalarise for scalable vectors");
         Decision = CM_Scalarize;
         Cost = ScalarizationCost;
       }


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