[DDG] Data Dependence Graph - DOT printer tests

[bmahjour]

Summary

This adds some tests to check the formatting of the dot file produced when using -dot-ddg

[Meinersbur]

LGTM

llvm/test/Analysis/DDG/print-dot-ddg.ll

+; RUN: opt -aa-pipeline=basic-aa -passes=dot-ddg -dot-ddg-filename-prefix=out.full < %s 2>&1 > /dev/null
+; RUN: FileCheck %s -input-file=out.full.foo.for.body.dot
+; RUN: opt -aa-pipeline=basic-aa -passes=dot-ddg -dot-ddg-filename-prefix=out.only -dot-ddg-only < %s 2>&1 > /dev/null
+; RUN: FileCheck %s -input-file=out.only.foo.for.body.dot -check-prefix=CHECK-ONLY
+
+target datalayout = "e-m:e-i64:64-n32:64-v256:256:256-v512:512:512"
+
+; Test the dot graph printer for a non-trivial DDG graph generated from
+; the following test case. In particular it tests that pi-blocks are
+; printed properly and that multiple memory dependencies on a single edge
+; are shown in the full dot graph.
+;
+; void foo(float * restrict A, float * restrict B, int n) {
+;   for (int i = 0; i < n; i++) {
+;     A[i] = A[i] + B[i];
+;     B[i+1] = A[i] + 1;
+;   }
+; }
+
+
+; CHECK: digraph "DDG for 'foo.for.body'"
+; CHECK-NEXT: label="DDG for 'foo.for.body'";
+; CHECK: {{Node0x.*}} [shape=record,label="{\<kind:root\>\nroot\n}"]
+; CHECK: {{Node0x.*}} -> {{Node0x.*}}[label="[rooted]"]
+; CHECK-COUNT-6: {{Node0x.*}} -> {{Node0x.*}}[label="[def-use]"]
+; CHECK-NOT: {{Node0x.*}} -> {{Node0x.*}}[label="[def-use]"]
+; CHECK: [shape=record,label="{\<kind:single-instruction\>\n  %arrayidx10 = getelementptr inbounds float, float* %B, i64 %indvars.iv.next\n}"];
+; CHECK: [shape=record,label="{\<kind:multi-instruction\>\n  %arrayidx = getelementptr inbounds float, float* %A, i64 %indvars.iv\n  %0 = load float, float* %arrayidx, align 4\n}"];
+; CHECK: {{Node0x.*}} -> {{Node0x.*}}[label="[consistent anti [0|<]!, consistent input [0|<]!]"]
+; CHECK: [shape=record,label="{\<kind:pi-block\>\n--- start of nodes in pi-block ---\n\<kind:single-instruction\>\n  %1 = load float, float* %arrayidx2, align 4\n\n\<kind:single-instruction\>\n  %add = fadd fast float %0, %1\n\n\<kind:single-instruction\>\n  store float %add, float* %arrayidx4, align 4\n\n\<kind:multi-instruction\>\n  %2 = load float, float* %arrayidx6, align 4\n  %add7 = fadd fast float %2, 1.000000e+00\n\n\<kind:single-instruction\>\n  store float %add7, float* %arrayidx10, align 4\n--- end of nodes in pi-block ---\n}"];
+
+; CHECK-ONLY: digraph "DDG for 'foo.for.body'"
+; CHECK-ONLY-NEXT: label="DDG for 'foo.for.body'";
+; CHECK-ONLY: [shape=record,label="{pi-block\nwith\n2 nodes\n}"];
+; CHECK-ONLY-COUNT-6: {{Node0x.*}} -> {{Node0x.*}}[label="[def-use]"];
+; CHECK-NOT: {{Node0x.*}} -> {{Node0x.*}}[label="[def-use]"];
+; CHECK-ONLY: [shape=record,label="{  %arrayidx10 = getelementptr inbounds float, float* %B, i64 %indvars.iv.next\n}"];
+; CHECK-ONLY: [shape=record,label="{  %arrayidx = getelementptr inbounds float, float* %A, i64 %indvars.iv\n  %0 = load float, float* %arrayidx, align 4\n}"];
+; CHECK-ONLY: {{Node0x.*}} -> {{Node0x.*}}[label="[memory]"]
+; CHECK-ONLY: [shape=record,label="{pi-block\nwith\n5 nodes\n}"];
+
+define void @foo(float* noalias %A, float* noalias %B, i32 signext %n) {
+entry:
+  %cmp1 = icmp sgt i32 %n, 0
+  br i1 %cmp1, label %for.body.preheader, label %for.end
+
+for.body.preheader:                               ; preds = %entry
+  %wide.trip.count = zext i32 %n to i64
+  br label %for.body
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %indvars.iv = phi i64 [ 0, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds float, float* %A, i64 %indvars.iv
+  %0 = load float, float* %arrayidx, align 4
+  %arrayidx2 = getelementptr inbounds float, float* %B, i64 %indvars.iv
+  %1 = load float, float* %arrayidx2, align 4
+  %add = fadd fast float %0, %1
+  %arrayidx4 = getelementptr inbounds float, float* %A, i64 %indvars.iv
+  store float %add, float* %arrayidx4, align 4
+  %arrayidx6 = getelementptr inbounds float, float* %A, i64 %indvars.iv
+  %2 = load float, float* %arrayidx6, align 4
+  %add7 = fadd fast float %2, 1.000000e+00
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %arrayidx10 = getelementptr inbounds float, float* %B, i64 %indvars.iv.next
+  store float %add7, float* %arrayidx10, align 4
+  %exitcond = icmp ne i64 %indvars.iv.next, %wide.trip.count
+  br i1 %exitcond, label %for.body, label %for.end.loopexit
+
+for.end.loopexit:                                 ; preds = %for.body
+  br label %for.end
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  ret void
+}