Teach the BranchProbabilityInfo pass to print its results, and use that

to bring it under direct test instead of merely indirectly testing it in
the BlockFrequencyInfo pass.

The next step is to start adding tests for the various heuristics
employed, and to start fixing those heuristics once they're under test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142778 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 93 insertions, 0 deletions

diff --git a/test/Analysis/BranchProbabilityInfo/basic.ll b/test/Analysis/BranchProbabilityInfo/basic.ll
new file mode 100644
index 0000000..74d06a1
--- /dev/null
+++ b/test/Analysis/BranchProbabilityInfo/basic.ll
@@ -0,0 +1,90 @@
+; RUN: opt < %s -analyze -branch-prob | FileCheck %s
+
+define i32 @test1(i32 %i, i32* %a) {
+; CHECK: Printing analysis {{.*}} for function 'test1'
+entry:
+  br label %body
+; CHECK: edge entry -> body probability is 16 / 16 = 100%
+
+body:
+  %iv = phi i32 [ 0, %entry ], [ %next, %body ]
+  %base = phi i32 [ 0, %entry ], [ %sum, %body ]
+  %arrayidx = getelementptr inbounds i32* %a, i32 %iv
+  %0 = load i32* %arrayidx
+  %sum = add nsw i32 %0, %base
+  %next = add i32 %iv, 1
+  %exitcond = icmp eq i32 %next, %i
+  br i1 %exitcond, label %exit, label %body
+; CHECK: edge body -> exit probability is 4 / 128
+; CHECK: edge body -> body probability is 124 / 128
+
+exit:
+  ret i32 %sum
+}
+
+define i32 @test2(i32 %i, i32 %a, i32 %b) {
+; CHECK: Printing analysis {{.*}} for function 'test2'
+entry:
+  %cond = icmp ult i32 %i, 42
+  br i1 %cond, label %then, label %else, !prof !0
+; CHECK: edge entry -> then probability is 64 / 68
+; CHECK: edge entry -> else probability is 4 / 68
+
+then:
+  br label %exit
+; CHECK: edge then -> exit probability is 16 / 16 = 100%
+
+else:
+  br label %exit
+; CHECK: edge else -> exit probability is 16 / 16 = 100%
+
+exit:
+  %result = phi i32 [ %a, %then ], [ %b, %else ]
+  ret i32 %result
+}
+
+!0 = metadata !{metadata !"branch_weights", i32 64, i32 4}
+
+define i32 @test3(i32 %i, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
+; CHECK: Printing analysis {{.*}} for function 'test3'
+entry:
+  switch i32 %i, label %case_a [ i32 1, label %case_b
+                                 i32 2, label %case_c
+                                 i32 3, label %case_d
+                                 i32 4, label %case_e ], !prof !1
+; CHECK: edge entry -> case_a probability is 4 / 80
+; CHECK: edge entry -> case_b probability is 4 / 80
+; CHECK: edge entry -> case_c probability is 64 / 80
+; CHECK: edge entry -> case_d probability is 4 / 80
+; CHECK: edge entry -> case_e probability is 4 / 80
+
+case_a:
+  br label %exit
+; CHECK: edge case_a -> exit probability is 16 / 16 = 100%
+
+case_b:
+  br label %exit
+; CHECK: edge case_b -> exit probability is 16 / 16 = 100%
+
+case_c:
+  br label %exit
+; CHECK: edge case_c -> exit probability is 16 / 16 = 100%
+
+case_d:
+  br label %exit
+; CHECK: edge case_d -> exit probability is 16 / 16 = 100%
+
+case_e:
+  br label %exit
+; CHECK: edge case_e -> exit probability is 16 / 16 = 100%
+
+exit:
+  %result = phi i32 [ %a, %case_a ],
+                    [ %b, %case_b ],
+                    [ %c, %case_c ],
+                    [ %d, %case_d ],
+                    [ %e, %case_e ]
+  ret i32 %result
+}
+
+!1 = metadata !{metadata !"branch_weights", i32 4, i32 4, i32 64, i32 4, i32 4}
diff --git a/test/Analysis/BranchProbabilityInfo/dg.exp b/test/Analysis/BranchProbabilityInfo/dg.exp
new file mode 100644
index 0000000..f200589
--- /dev/null
+++ b/test/Analysis/BranchProbabilityInfo/dg.exp
@@ -0,0 +1,3 @@
+load_lib llvm.exp
+
+RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll,c,cpp}]]