Files
clang-p2996/llvm/test/Transforms/TailCallElim/deopt-bundle.ll
Chijun Sima 8b5de48d62 [TailCallElim] Preserve DT and PDT
Summary:
Previously, in the NewPM pipeline, TailCallElim recalculates the DomTree when it modifies any instruction in the Function.
For example,
```
CallInst *CI = dyn_cast<CallInst>(&I);
...
CI->setTailCall();
Modified = true;
...
if (!Modified || ...)
  return PreservedAnalyses::all();
```
After applying this patch, the DomTree only recalculates if needed (plus an extra insertEdge() + an extra deleteEdge() call).

When optimizing SQLite with `-passes="default<O3>"` pipeline of the newPM, the number of DomTree recalculation decreases by 6.2%, the number of nodes visited by DFS decreases by 2.9%. The time used by DomTree will decrease approximately 1%~2.5% after applying the patch.
 
Statistics:
```
Before the patch:
 23010 dom-tree-stats               - Number of DomTree recalculations
489264 dom-tree-stats               - Number of nodes visited by DFS -- DomTree
After the patch:
 21581 dom-tree-stats               - Number of DomTree recalculations
475088 dom-tree-stats               - Number of nodes visited by DFS -- DomTree
```

Reviewers: kuhar, dmgreen, brzycki, grosser, davide

Reviewed By: kuhar, brzycki

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D49982

llvm-svn: 338954
2018-08-04 08:13:47 +00:00

58 lines
1.1 KiB
LLVM

; RUN: opt < %s -tailcallelim -verify-dom-info -S | FileCheck %s
define i32 @f_1(i32 %x) {
; CHECK-LABEL: @f_1(
wentry:
%cond = icmp ugt i32 %x, 0
br i1 %cond, label %return, label %body
body:
; CHECK: body:
; CHECK: call i32 @f_1(i32 %y) [ "deopt"() ]
%y = add i32 %x, 1
%tmp = call i32 @f_1(i32 %y) [ "deopt"() ]
ret i32 0
return:
ret i32 1
}
define i32 @f_2(i32 %x) {
; CHECK-LABEL: @f_2
entry:
%cond = icmp ugt i32 %x, 0
br i1 %cond, label %return, label %body
body:
; CHECK: body:
; CHECK: call i32 @f_2(i32 %y) [ "unknown"() ]
%y = add i32 %x, 1
%tmp = call i32 @f_2(i32 %y) [ "unknown"() ]
ret i32 0
return:
ret i32 1
}
declare void @func()
define void @f_3(i1 %B) personality i8 42 {
; CHECK-LABEL: @f_3(
entry:
invoke void @func()
to label %exit unwind label %merge
merge:
%cs1 = catchswitch within none [label %catch] unwind to caller
catch:
; CHECK: catch:
; CHECK: call void @f_3(i1 %B) [ "funclet"(token %cp) ]
%cp = catchpad within %cs1 []
call void @f_3(i1 %B) [ "funclet"(token %cp) ]
ret void
exit:
ret void
}