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llvm-mirror/test/Transforms/CallSiteSplitting/musttail.ll
Fedor Indutny 5f6d64098f [CallSiteSplitting] properly split musttail calls
Summary:
`musttail` calls can't be naively splitted. The split blocks must
include not only the call instruction itself, but also (optional)
`bitcast` and `return` instructions that follow it.

Clone `bitcast` and `ret`, place them into the split blocks, and
remove the tail block when done.

Reviewers: junbuml, mcrosier, davidxl, davide, fhahn

Reviewed By: fhahn

Subscribers: JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D43729

llvm-svn: 326666
2018-03-03 21:40:14 +00:00

76 lines
1.8 KiB
LLVM

; RUN: opt < %s -callsite-splitting -S | FileCheck %s
;CHECK-LABEL: @caller
;CHECK-LABEL: Top.split:
;CHECK: %ca1 = musttail call i8* @callee(i8* null, i8* %b)
;CHECK: %cb2 = bitcast i8* %ca1 to i8*
;CHECK: ret i8* %cb2
;CHECK-LABEL: TBB.split
;CHECK: %ca3 = musttail call i8* @callee(i8* nonnull %a, i8* null)
;CHECK: %cb4 = bitcast i8* %ca3 to i8*
;CHECK: ret i8* %cb4
define i8* @caller(i8* %a, i8* %b) {
Top:
%c = icmp eq i8* %a, null
br i1 %c, label %Tail, label %TBB
TBB:
%c2 = icmp eq i8* %b, null
br i1 %c2, label %Tail, label %End
Tail:
%ca = musttail call i8* @callee(i8* %a, i8* %b)
%cb = bitcast i8* %ca to i8*
ret i8* %cb
End:
ret i8* null
}
define i8* @callee(i8* %a, i8* %b) noinline {
ret i8* %a
}
;CHECK-LABEL: @no_cast_caller
;CHECK-LABEL: Top.split:
;CHECK: %ca1 = musttail call i8* @callee(i8* null, i8* %b)
;CHECK: ret i8* %ca1
;CHECK-LABEL: TBB.split
;CHECK: %ca2 = musttail call i8* @callee(i8* nonnull %a, i8* null)
;CHECK: ret i8* %ca2
define i8* @no_cast_caller(i8* %a, i8* %b) {
Top:
%c = icmp eq i8* %a, null
br i1 %c, label %Tail, label %TBB
TBB:
%c2 = icmp eq i8* %b, null
br i1 %c2, label %Tail, label %End
Tail:
%ca = musttail call i8* @callee(i8* %a, i8* %b)
ret i8* %ca
End:
ret i8* null
}
;CHECK-LABEL: @void_caller
;CHECK-LABEL: Top.split:
;CHECK: musttail call void @void_callee(i8* null, i8* %b)
;CHECK: ret void
;CHECK-LABEL: TBB.split
;CHECK: musttail call void @void_callee(i8* nonnull %a, i8* null)
;CHECK: ret void
define void @void_caller(i8* %a, i8* %b) {
Top:
%c = icmp eq i8* %a, null
br i1 %c, label %Tail, label %TBB
TBB:
%c2 = icmp eq i8* %b, null
br i1 %c2, label %Tail, label %End
Tail:
musttail call void @void_callee(i8* %a, i8* %b)
ret void
End:
ret void
}
define void @void_callee(i8* %a, i8* %b) noinline {
ret void
}