Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl" (#2)

This reverts commit r206628, reapplying r206622 (and r206626).

Two tests are failing only on buildbots [1][2]: i.e., I can't reproduce
on Darwin, and Chandler can't reproduce on Linux.  Asan and valgrind
don't tell us anything, but we're hoping the msan bot will catch it.

So, I'm applying this again to get more feedback from the bots.  I'll
leave it in long enough to trigger builds in at least the sanitizer
buildbots (it was failing for reasons unrelated to my commit last time
it was in), and hopefully a few others.... and then I expect to revert a
third time.

[1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816
[2]: http://llvm-amd64.freebsd.your.org/b/builders/clang-i386-freebsd/builds/18445

llvm-svn: 206666

1 files changed, 50 insertions, 0 deletions

diff --git a/llvm/test/Analysis/BlockFrequencyInfo/bad_input.ll b/llvm/test/Analysis/BlockFrequencyInfo/bad_input.ll
new file mode 100644
index 00000000000..bcdc1e6f0bc
--- /dev/null
+++ b/llvm/test/Analysis/BlockFrequencyInfo/bad_input.ll
@@ -0,0 +1,50 @@
+; RUN: opt < %s -analyze -block-freq | FileCheck %s
+
+declare void @g(i32 %x)
+
+; CHECK-LABEL: Printing analysis {{.*}} for function 'branch_weight_0':
+; CHECK-NEXT: block-frequency-info: branch_weight_0
+define void @branch_weight_0(i32 %a) {
+; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
+entry:
+  br label %for.body
+
+; Check that we get 1,4 instead of 0,3.
+; CHECK-NEXT: for.body: float = 4.0,
+for.body:
+  %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  call void @g(i32 %i)
+  %inc = add i32 %i, 1
+  %cmp = icmp ugt i32 %inc, %a
+  br i1 %cmp, label %for.end, label %for.body, !prof !0
+
+; CHECK-NEXT: for.end: float = 1.0, int = [[ENTRY]]
+for.end:
+  ret void
+}
+
+!0 = metadata !{metadata !"branch_weights", i32 0, i32 3}
+
+; CHECK-LABEL: Printing analysis {{.*}} for function 'infinite_loop'
+; CHECK-NEXT: block-frequency-info: infinite_loop
+define void @infinite_loop(i1 %x) {
+; CHECK-NEXT: entry: float = 1.0, int = [[ENTRY:[0-9]+]]
+entry:
+  br i1 %x, label %for.body, label %for.end, !prof !1
+
+; Check that the loop scale maxes out at 4096, giving 2048 here.
+; CHECK-NEXT: for.body: float = 2048.0,
+for.body:
+  %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  call void @g(i32 %i)
+  %inc = add i32 %i, 1
+  br label %for.body
+
+; Check that the exit weight is half of entry, since half is lost in the
+; infinite loop above.
+; CHECK-NEXT: for.end: float = 0.5,
+for.end:
+  ret void
+}
+
+!1 = metadata !{metadata !"branch_weights", i32 1, i32 1}