Index: lib/Transforms/Scalar/LoopInterchange.cpp =================================================================== --- lib/Transforms/Scalar/LoopInterchange.cpp +++ lib/Transforms/Scalar/LoopInterchange.cpp @@ -173,9 +173,6 @@ } } - // We don't have a DepMatrix to check legality return false. - if (DepMatrix.empty()) - return false; return true; } Index: test/Transforms/LoopInterchange/interchange-no-deps.ll =================================================================== --- test/Transforms/LoopInterchange/interchange-no-deps.ll +++ test/Transforms/LoopInterchange/interchange-no-deps.ll @@ -0,0 +1,44 @@ +; RUN: opt < %s -loop-interchange -simplifycfg -S | FileCheck %s + +; no_deps_interchange just access a single nested array and can be interchange. +define i32 @no_deps_interchange([1024 x i32]* nocapture %Arr, i32 %k) local_unnamed_addr #0 { +entry: + br label %for.body + +for.body: ; preds = %entry, %for.cond.cleanup3 + %indvars.iv19 = phi i64 [ 0, %entry ], [ %indvars.iv.next20, %for.cond.cleanup3 ] + br label %for.body4 + +for.body4: ; preds = %for.body, %for.body4 + %indvars.iv = phi i64 [ 0, %for.body ], [ %indvars.iv.next, %for.body4 ] + %arrayidx6 = getelementptr inbounds [1024 x i32], [1024 x i32]* %Arr, i64 %indvars.iv, i64 %indvars.iv19 + store i32 0, i32* %arrayidx6, align 4 + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %exitcond = icmp ne i64 %indvars.iv.next, 1024 + br i1 %exitcond, label %for.body4, label %for.cond.cleanup3 + +for.cond.cleanup3: ; preds = %for.body4 + %indvars.iv.next20 = add nuw nsw i64 %indvars.iv19, 1 + %exitcond21 = icmp ne i64 %indvars.iv.next20, 1024 + br i1 %exitcond21, label %for.body, label %for.cond.cleanup + + +for.cond.cleanup: ; preds = %for.cond.cleanup3 + ret i32 0 +} + +; CHECK-LABEL: @no_deps_interchange +; CHECK-LABEL: entry: +; CHECK-NEXT: br label %for.body4 + +; CHECK-LABEL: for.body: ; preds = %for.body4, %for.body +; CHECK: %indvars.iv19 = phi i64 [ %indvars.iv.next20, %for.body ], [ 0, %for.body4 ] +; CHECK: br i1 %exitcond21, label %for.body, label %for.body4.split + +; CHECK-LABEL: for.body4: ; preds = %entry, %for.body4.split +; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %for.body4.split ], [ 0, %entry ] +; CHECK: br label %for.body + +; CHECK-LABEL: for.body4.split: ; preds = %for.body +; CHECK: %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 +; CHECK: br i1 %exitcond, label %for.body4, label %for.cond.cleanup