StructurizeCFG: Use a reverse post-order traversal

[oota-llvm.git] / test / Transforms / StructurizeCFG / post-order-traversal-bug.ll

diff --git a/test/Transforms/StructurizeCFG/post-order-traversal-bug.ll b/test/Transforms/StructurizeCFG/post-order-traversal-bug.ll
new file mode 100644 (file)
index 0000000..740b3d1
--- /dev/null
+++ b/test/Transforms/StructurizeCFG/post-order-traversal-bug.ll
@@ -0,0 +1,100 @@
+; RUN: opt -S -structurizecfg %s -o - | FileCheck %s
+
+; The structurize cfg pass used to do a post-order traversal to generate a list
+; of ; basic blocks and then operate on the list in reverse.  This led to bugs,
+; because sometimes successors would be visited before their predecessors.
+; The fix for this was to do a reverse post-order traversal which is what the
+; algorithm requires.
+
+; Function Attrs: nounwind
+define void @test(float* nocapture %out, i32 %K1, float* nocapture readonly %nr) {
+
+; CHECK: entry:
+; CHECK: br label %for.body
+entry:
+  br label %for.body
+
+; CHECK: for.body:
+; CHECK: br i1 %{{[0-9]+}}, label %lor.lhs.false, label %Flow
+for.body:                                         ; preds = %for.body.backedge, %entry
+  %indvars.iv = phi i64 [ %indvars.iv.be, %for.body.backedge ], [ 1, %entry ]
+  %best_val.027 = phi float [ %best_val.027.be, %for.body.backedge ], [ 5.000000e+01, %entry ]
+  %prev_start.026 = phi i32 [ %tmp26, %for.body.backedge ], [ 0, %entry ]
+  %best_count.025 = phi i32 [ %best_count.025.be, %for.body.backedge ], [ 0, %entry ]
+  %tmp0 = trunc i64 %indvars.iv to i32
+  %cmp1 = icmp eq i32 %tmp0, %K1
+  br i1 %cmp1, label %if.then, label %lor.lhs.false
+
+; CHECK: lor.lhs.false:
+; CHECK: br label %Flow
+lor.lhs.false:                                    ; preds = %for.body
+  %arrayidx = getelementptr inbounds float* %nr, i64 %indvars.iv
+  %tmp1 = load float* %arrayidx, align 4
+  %tmp2 = add nsw i64 %indvars.iv, -1
+  %arrayidx2 = getelementptr inbounds float* %nr, i64 %tmp2
+  %tmp3 = load float* %arrayidx2, align 4
+  %cmp3 = fcmp une float %tmp1, %tmp3
+  br i1 %cmp3, label %if.then, label %for.body.1
+
+; CHECK: Flow:
+; CHECK: br i1 %{{[0-9]+}}, label %if.then, label %Flow1
+
+; CHECK: if.then:
+; CHECK: br label %Flow1
+if.then:                                          ; preds = %lor.lhs.false, %for.body
+  %sub4 = sub nsw i32 %tmp0, %prev_start.026
+  %tmp4 = add nsw i64 %indvars.iv, -1
+  %arrayidx8 = getelementptr inbounds float* %nr, i64 %tmp4
+  %tmp5 = load float* %arrayidx8, align 4
+  br i1 %cmp1, label %for.end, label %for.body.1
+
+; CHECK: for.end:
+; CHECK: ret void
+for.end:                                          ; preds = %for.body.1, %if.then
+  %best_val.0.lcssa = phi float [ %best_val.233, %for.body.1 ], [ %tmp5, %if.then ]
+  store float %best_val.0.lcssa, float* %out, align 4
+  ret void
+
+; CHECK: Flow1
+; CHECK: br i1 %{{[0-9]}}, label %for.body.1, label %Flow2
+
+; CHECK: for.body.1:
+; CHECK: br i1 %{{[0-9]+}}, label %for.body.6, label %Flow3
+for.body.1:                                       ; preds = %if.then, %lor.lhs.false
+  %best_val.233 = phi float [ %tmp5, %if.then ], [ %best_val.027, %lor.lhs.false ]
+  %best_count.231 = phi i32 [ %sub4, %if.then ], [ %best_count.025, %lor.lhs.false ]
+  %indvars.iv.next.454 = add nsw i64 %indvars.iv, 5
+  %tmp22 = trunc i64 %indvars.iv.next.454 to i32
+  %cmp1.5 = icmp eq i32 %tmp22, %K1
+  br i1 %cmp1.5, label %for.end, label %for.body.6
+
+; CHECK: Flow2:
+; CHECK: br i1 %{{[0-9]+}}, label %for.end, label %for.body
+
+; CHECK: for.body.6:
+; CHECK: br i1 %cmp5.6, label %if.then6.6, label %for.body.backedge
+for.body.6:                                       ; preds = %for.body.1
+  %indvars.iv.next.559 = add nsw i64 %indvars.iv, 6
+  %tmp26 = trunc i64 %indvars.iv.next.559 to i32
+  %sub4.6 = sub nsw i32 %tmp26, %tmp22
+  %cmp5.6 = icmp slt i32 %best_count.231, %sub4.6
+  br i1 %cmp5.6, label %if.then6.6, label %for.body.backedge
+
+; CHECK: if.then6.6
+; CHECK: br label %for.body.backedge
+if.then6.6:                                       ; preds = %for.body.6
+  %arrayidx8.6 = getelementptr inbounds float* %nr, i64 %indvars.iv.next.454
+  %tmp29 = load float* %arrayidx8.6, align 4
+  br label %for.body.backedge
+
+; CHECK: Flow3:
+; CHECK: br label %Flow2
+
+; CHECK: for.body.backedge:
+; CHECK: br label %Flow3
+for.body.backedge:                                ; preds = %if.then6.6, %for.body.6
+  %best_val.027.be = phi float [ %tmp29, %if.then6.6 ], [ %best_val.233, %for.body.6 ]
+  %best_count.025.be = phi i32 [ %sub4.6, %if.then6.6 ], [ %best_count.231, %for.body.6 ]
+  %indvars.iv.be = add nsw i64 %indvars.iv, 7
+  br label %for.body
+}