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llvm-mirror/test/Transforms/CallSiteSplitting/lpad.ll
Taewook Oh 5dc6a73122 [CallSiteSplitting] Do not perform callsite splitting inside landing pad
Summary:
If the callsite is inside landing pad, do not perform callsite splitting.

Callsite splitting uses utility function llvm::DuplicateInstructionsInSplitBetween, which eventually calls llvm::SplitEdge. llvm::SplitEdge calls llvm::SplitCriticalEdge with an assumption that the function returns nullptr only when the target edge is not a critical edge (and further assumes that if the return value was not nullptr, the predecessor of the original target edge always has a single successor because critical edge splitting was successful). However, this assumtion is not true because SplitCriticalEdge returns nullptr if the destination block is a landing pad. This invalid assumption results assertion failure.

Fundamental solution might be fixing llvm::SplitEdge to not to rely on the invalid assumption. However, it'll involve a lot of work because current API assumes that llvm::SplitEdge never fails. Instead, this patch makes callsite splitting to not to attempt splitting if the callsite is in a landing pad.

Attached test case will crash with assertion failure without the fix.

Reviewers: fhahn, junbuml, dberlin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45130

llvm-svn: 329250
2018-04-05 04:16:23 +00:00

41 lines
852 B
LLVM

; RUN: opt -S -callsite-splitting < %s | FileCheck %s
;
; Make sure that the callsite is not splitted by checking that there's only one
; call to @callee.
; CHECK-LABEL: @caller
; CHECK-LABEL: lpad
; CHECK: call void @callee
; CHECK-NOT: call void @callee
declare void @foo(i1* %p);
declare void @bar(i1* %p);
declare dso_local i32 @__gxx_personality_v0(...)
define void @caller(i1* %p) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
%0 = icmp eq i1* %p, null
br i1 %0, label %bb1, label %bb2
bb1:
invoke void @foo(i1* %p) to label %end1 unwind label %lpad
bb2:
invoke void @bar(i1* %p) to label %end2 unwind label %lpad
lpad:
%1 = landingpad { i8*, i32 } cleanup
call void @callee(i1* %p)
resume { i8*, i32 } %1
end1:
ret void
end2:
ret void
}
define internal void @callee(i1* %p) {
ret void
}