diff options
| author | Manman Ren <manman.ren@gmail.com> | 2014-01-27 23:39:03 +0000 |
|---|---|---|
| committer | Manman Ren <manman.ren@gmail.com> | 2014-01-27 23:39:03 +0000 |
| commit | aa6627016ff797a0b206791d170aa7e677096553 (patch) | |
| tree | 47bfb0fdea769fcb8932872907583e0f83e7877e /test | |
| parent | 01df6842c1e8890d8f529683ed6d6e7b6bb172d8 (diff) | |
| download | llvm-aa6627016ff797a0b206791d170aa7e677096553.tar.gz llvm-aa6627016ff797a0b206791d170aa7e677096553.tar.bz2 llvm-aa6627016ff797a0b206791d170aa7e677096553.tar.xz | |
PGO branch weight: keep halving the weights until they can fit into
uint32.
When folding branches to common destination, the updated branch weights
can exceed uint32 by more than factor of 2. We should keep halving the
weights until they can fit into uint32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200262 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test')
| -rw-r--r-- | test/Transforms/SimplifyCFG/preserve-branchweights.ll | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/test/Transforms/SimplifyCFG/preserve-branchweights.ll b/test/Transforms/SimplifyCFG/preserve-branchweights.ll index 67f5636573..bdd25ba805 100644 --- a/test/Transforms/SimplifyCFG/preserve-branchweights.ll +++ b/test/Transforms/SimplifyCFG/preserve-branchweights.ll @@ -338,6 +338,32 @@ c: ret void } +;; When folding branches to common destination, the updated branch weights +;; can exceed uint32 by more than factor of 2. We should keep halving the +;; weights until they can fit into uint32. +@max_regno = common global i32 0, align 4 +define void @test14(i32* %old, i32 %final) { +; CHECK-LABEL: @test14 +; CHECK: br i1 %or.cond, label %for.exit, label %for.inc, !prof !10 +for.cond: + br label %for.cond2 +for.cond2: + %i.1 = phi i32 [ %inc19, %for.inc ], [ 0, %for.cond ] + %bit.0 = phi i32 [ %shl, %for.inc ], [ 1, %for.cond ] + %tobool = icmp eq i32 %bit.0, 0 + br i1 %tobool, label %for.exit, label %for.body3, !prof !10 +for.body3: + %v3 = load i32* @max_regno, align 4 + %cmp4 = icmp eq i32 %i.1, %v3 + br i1 %cmp4, label %for.exit, label %for.inc, !prof !11 +for.inc: + %shl = shl i32 %bit.0, 1 + %inc19 = add nsw i32 %i.1, 1 + br label %for.cond2 +for.exit: + ret void +} + !0 = metadata !{metadata !"branch_weights", i32 3, i32 5} !1 = metadata !{metadata !"branch_weights", i32 1, i32 1} !2 = metadata !{metadata !"branch_weights", i32 1, i32 2} @@ -348,6 +374,8 @@ c: !7 = metadata !{metadata !"branch_weights", i32 33, i32 9, i32 8, i32 7} !8 = metadata !{metadata !"branch_weights", i32 33, i32 9, i32 8} !9 = metadata !{metadata !"branch_weights", i32 7, i32 6} +!10 = metadata !{metadata !"branch_weights", i32 672646, i32 21604207} +!11 = metadata !{metadata !"branch_weights", i32 6960, i32 21597248} ; CHECK: !0 = metadata !{metadata !"branch_weights", i32 5, i32 11} ; CHECK: !1 = metadata !{metadata !"branch_weights", i32 1, i32 5} @@ -359,4 +387,6 @@ c: ; CHECK: !7 = metadata !{metadata !"branch_weights", i32 17, i32 9, i32 8, i32 7, i32 17} ; CHECK: !8 = metadata !{metadata !"branch_weights", i32 24, i32 33} ; CHECK: !9 = metadata !{metadata !"branch_weights", i32 8, i32 33} -; CHECK-NOT: !9 +;; The false weight prints out as a negative integer here, but inside llvm, we +;; treat the weight as an unsigned integer. +; CHECK: !10 = metadata !{metadata !"branch_weights", i32 112017436, i32 -735157296} |