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| author | Alon Zakai <azakai@google.com> | 2021-08-17 14:26:24 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-08-17 21:26:24 +0000 |
| commit | b82be0fe1abd3c56cc85150c76efbd66db6fe32e (patch) | |
| tree | 886cf25d9cfd2bd38c18cbdcf60b0c7386a1f50d /test/lit/passes/local-cse.wast | |
| parent | d1bea49163be364d6f8b277b35510555211374b5 (diff) | |
| download | binaryen-b82be0fe1abd3c56cc85150c76efbd66db6fe32e.tar.gz binaryen-b82be0fe1abd3c56cc85150c76efbd66db6fe32e.tar.bz2 binaryen-b82be0fe1abd3c56cc85150c76efbd66db6fe32e.zip | |
LocalCSE: ignore traps (#4085)
If we replace
A
A
A
with
(local.set A)
(local.get)
(local.get)
then it is ok for A to trap (so long as it does so deterministically), as if
it does trap then the first appearance will do so, and the others not
be reached anyhow.
This helps GC code as often there are repeated struct.gets and such that
may trap.
Diffstat (limited to 'test/lit/passes/local-cse.wast')
| -rw-r--r-- | test/lit/passes/local-cse.wast | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/test/lit/passes/local-cse.wast b/test/lit/passes/local-cse.wast index 5cdf712f8..6d1b8a824 100644 --- a/test/lit/passes/local-cse.wast +++ b/test/lit/passes/local-cse.wast @@ -266,20 +266,21 @@ ) ;; CHECK: (func $loads + ;; CHECK-NEXT: (local $0 i32) ;; CHECK-NEXT: (drop - ;; CHECK-NEXT: (i32.load - ;; CHECK-NEXT: (i32.const 10) + ;; CHECK-NEXT: (local.tee $0 + ;; CHECK-NEXT: (i32.load + ;; CHECK-NEXT: (i32.const 10) + ;; CHECK-NEXT: ) ;; CHECK-NEXT: ) ;; CHECK-NEXT: ) ;; CHECK-NEXT: (drop - ;; CHECK-NEXT: (i32.load - ;; CHECK-NEXT: (i32.const 10) - ;; CHECK-NEXT: ) + ;; CHECK-NEXT: (local.get $0) ;; CHECK-NEXT: ) ;; CHECK-NEXT: ) (func $loads - ;; The possible trap on loads prevents optimization. - ;; TODO: optimize that too + ;; The possible trap on loads does not prevent optimization, since if we + ;; trap then it doesn't matter that we replaced the later expression. (drop (i32.load (i32.const 10)) ) |