RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-12-01 07:10:37 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[Loop Peeling] Fix the bug with IDom setting for exit loops

Browse Source 
It is possible that loop exit has two predecessors in a loop body.
In this case after the peeling the iDom of the exit should be a clone of
iDom of original exit but no a clone of a block coming to this exit.

Reviewers: reames, fhahn
Reviewed By: reames
Subscribers: hiraditya, zzheng, llvm-commits
Differential Revision: https://reviews.llvm.org/D64618

llvm-svn: 366050
This commit is contained in:
Serguei Katkov 2019-07-15 09:13:11 +00:00
parent 953b5772e9
commit 9ce058433d
2 changed files with 73 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
lib/Transforms/Utils/LoopUnrollPeel.cpp
View File

@ -583,6 +583,18 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
SmallVector<std::pair<BasicBlock *, BasicBlock *>, 4> ExitEdges;
L->getExitEdges(ExitEdges);
DenseMap<BasicBlock *, BasicBlock *> ExitIDom;
if (DT) {
assert(L->hasDedicatedExits() && "No dedicated exits?");
for (auto Edge : ExitEdges) {
if (ExitIDom.count(Edge.second))
continue;
BasicBlock *BB = DT->getNode(Edge.second)->getIDom()->getBlock();
assert(L->contains(BB) && "IDom is not in a loop");
ExitIDom[Edge.second] = BB;
}
}
Function *F = Header->getParent();
// Set up all the necessary basic blocks. It is convenient to split the
@ -675,9 +687,9 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
// latter is the first cloned loop body, as original PreHeader dominates
// the original loop body.
if (Iter == 0)
for (auto Edge : ExitEdges)
DT->changeImmediateDominator(Edge.second,
cast<BasicBlock>(LVMap[Edge.first]));
for (auto Exit : ExitIDom)
DT->changeImmediateDominator(Exit.first,
cast<BasicBlock>(LVMap[Exit.second]));
#ifdef EXPENSIVE_CHECKS
assert(DT->verify(DominatorTree::VerificationLevel::Fast));
#endif
@ -719,6 +731,9 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
// We modified the loop, update SE.
SE->forgetTopmostLoop(L);
// Finally DomtTree must be correct.
assert(DT->verify(DominatorTree::VerificationLevel::Fast));
// FIXME: Incrementally update loop-simplify
simplifyLoop(L, DT, LI, SE, AC, nullptr, PreserveLCSSA);

55
test/Transforms/LoopUnroll/peel-loop-pgo-deopt-idom.ll Normal file
View File

@ -0,0 +1,55 @@
; REQUIRES: asserts
; RUN: opt < %s -S -debug-only=loop-unroll -loop-unroll -unroll-runtime -unroll-peel-multi-deopt-exit 2>&1 | FileCheck %s
; RUN: opt < %s -S -debug-only=loop-unroll -unroll-peel-multi-deopt-exit -passes='require<profile-summary>,function(require<opt-remark-emit>,unroll)' 2>&1 | FileCheck %s
; Regression test for setting the correct idom for exit blocks.
; CHECK: Loop Unroll: F[basic]
; CHECK: PEELING loop %for.body with iteration count 1!
define i32 @basic(i32* %p, i32 %k, i1 %c1, i1 %c2) #0 !prof !3 {
entry:
%cmp3 = icmp slt i32 0, %k
br i1 %cmp3, label %for.body.lr.ph, label %for.end
for.body.lr.ph: ; preds = %entry
br label %for.body
for.body: ; preds = %for.body.lr.ph, %for.body
%i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %latch ]
%p.addr.04 = phi i32* [ %p, %for.body.lr.ph ], [ %incdec.ptr, %latch ]
%incdec.ptr = getelementptr inbounds i32, i32* %p.addr.04, i32 1
store i32 %i.05, i32* %p.addr.04, align 4
%inc = add nsw i32 %i.05, 1
%cmp = icmp slt i32 %inc, %k
br i1 %c1, label %continue, label %to_side_exit
continue:
br i1 %c2, label %latch, label %side_exit, !prof !2
latch:
br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge, !prof !1
for.cond.for.end_crit_edge: ; preds = %for.body
br label %for.end
to_side_exit:
br i1 %c2, label %continue, label %side_exit, !prof !2
for.end: ; preds = %for.cond.for.end_crit_edge, %entry
%res = phi i32 [ 0, %entry ], [ %inc, %for.cond.for.end_crit_edge ]
ret i32 %res
side_exit:
%rval = call i32(...) @llvm.experimental.deoptimize.i32() [ "deopt"(i32 %inc) ]
ret i32 %rval
}
declare i32 @llvm.experimental.deoptimize.i32(...)
attributes #0 = { nounwind }
!1 = !{!"branch_weights", i32 1, i32 1}
!2 = !{!"branch_weights", i32 1, i32 0}
!3 = !{!"function_entry_count", i64 1}