[BPI] Refactor post domination calculation and simple fix for ColdCall

Collection of PostDominatedByUnreachable and PostDominatedByColdCall have been
split out of heuristics itself. Update of the data happens now for each basic
block (before update for PostDominatedByColdCall might be skipped if
unreachable or matadata heuristic handled this basic block).

This separation allows re-ordering of heuristics without loosing
the post-domination information.

Reviewers: sanjoy, junbuml, vsk, chandlerc, reames

Reviewed By: chandlerc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31701

llvm-svn: 300029

1 files changed, 37 insertions, 0 deletions

diff --git a/llvm/test/Analysis/BranchProbabilityInfo/basic.ll b/llvm/test/Analysis/BranchProbabilityInfo/basic.ll
index 67d3e9e850c..94ea5a3d1d8 100644
--- a/llvm/test/Analysis/BranchProbabilityInfo/basic.ll
+++ b/llvm/test/Analysis/BranchProbabilityInfo/basic.ll
@@ -143,6 +143,43 @@ exit:
 
 declare i32 @regular_function(i32 %i)
 
+define i32 @test_cold_call_sites_with_prof(i32 %a, i32 %b, i1 %flag, i1 %flag2) {
+; CHECK: Printing analysis {{.*}} for function 'test_cold_call_sites_with_prof'
+entry:
+  br i1 %flag, label %then, label %else
+; CHECK: edge entry -> then probability is 0x07878788 / 0x80000000 = 5.88%
+; CHECK: edge entry -> else probability is 0x78787878 / 0x80000000 = 94.12% [HOT edge]
+
+then:
+  br i1 %flag2, label %then2, label %else2, !prof !3
+; CHECK: edge then -> then2 probability is 0x7ebb907a / 0x80000000 = 99.01% [HOT edge]
+; CHECK: edge then -> else2 probability is 0x01446f86 / 0x80000000 = 0.99%
+
+then2:
+  br label %join
+; CHECK: edge then2 -> join probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
+
+else2:
+  br label %join
+; CHECK: edge else2 -> join probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
+
+join:
+  %joinresult = phi i32 [ %a, %then2 ], [ %b, %else2 ]
+  call void @coldfunc()
+  br label %exit
+; CHECK: edge join -> exit probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
+
+else:
+  br label %exit
+; CHECK: edge else -> exit probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
+
+exit:
+  %result = phi i32 [ %joinresult, %join ], [ %b, %else ]
+  ret i32 %result
+}
+
+!3 = !{!"branch_weights", i32 100, i32 1}
+
 define i32 @test_cold_call_sites(i32* %a) {
 ; Test that edges to blocks post-dominated by cold call sites
 ; are marked as not expected to be taken.