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| author | DianQK <dianqk@dianqk.net> | 2023-09-19 17:57:30 +0800 |
|---|---|---|
| committer | DianQK <dianqk@dianqk.net> | 2023-09-20 07:21:49 +0800 |
| commit | 96ea48ff5dcba46af350f5300eafd7f7394ba606 (patch) | |
| tree | 5197a2e50cc98a47c7b73696de3ccd3313385e35 /llvm/lib/IR/Module.cpp | |
| parent | 40b0ab287f9f5c58fa35a9a97cc49f104bef45ed (diff) | |
| download | llvm-96ea48ff5dcba46af350f5300eafd7f7394ba606.zip llvm-96ea48ff5dcba46af350f5300eafd7f7394ba606.tar.gz llvm-96ea48ff5dcba46af350f5300eafd7f7394ba606.tar.bz2 | |
[SimplifyCFG] Hoist common instructions on Switch.
Sink common instructions are not always performance friendly. We need to implement hoist common instructions on switch instruction to solve the following problem:
```
define i1 @foo(i64 %a, i64 %b, i64 %c, i64 %d) {
start:
%test = icmp eq i64 %a, %d
br i1 %test, label %switch_bb, label %exit
switch_bb: ; preds = %start
switch i64 %a, label %bb0 [
i64 1, label %bb1
i64 2, label %bb2
]
bb0: ; preds = %switch_bb
%0 = icmp eq i64 %b, %c
br label %exit
bb1: ; preds = %switch_bb
%1 = icmp eq i64 %b, %c
br label %exit
bb2: ; preds = %switch_bb
%2 = icmp eq i64 %b, %c
br label %exit
exit: ; preds = %bb2, %bb1, %bb0, %start
%result = phi i1 [ false, %start ], [ %0, %bb0 ], [ %1, %bb1 ], [ %2, %bb2 ]
ret i1 %result
}
```
The pre-commit test is D156617.
Reviewed By: XChy, nikic
Differential Revision: https://reviews.llvm.org/D155711
Diffstat (limited to 'llvm/lib/IR/Module.cpp')
0 files changed, 0 insertions, 0 deletions