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[CoroSplit] AllocaUseVisitor visits insertvalue/insertelement (#156788)

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Pointers to allocas might be escaped by users of
`insertvalue/insertelement`. `AllocaUseVisitor` should visit these
instructions so that CoroSplit can successfully determine which allocas
should live on the frame.
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Weibo He 2025-09-11 11:28:21 +08:00 committed by GitHub
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commit 2b058411e9
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10
llvm/lib/Transforms/Coroutines/SpillUtils.cpp
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@ -183,6 +183,16 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
handleAlias(I);
}
void visitInsertElementInst(InsertElementInst &I) {
enqueueUsers(I);
handleAlias(I);
}
void visitInsertValueInst(InsertValueInst &I) {
enqueueUsers(I);
handleAlias(I);
}
void visitStoreInst(StoreInst &SI) {
// Regardless whether the alias of the alloca is the value operand or the
// pointer operand, we need to assume the alloca is been written.

62
llvm/test/Transforms/Coroutines/coro-alloca-09.ll Normal file
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@ -0,0 +1,62 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; Tests that CoroSplit can succesfully determine allocas should live on the frame
; if their aliases are used across suspension points through insertvalue/insertelement.
; RUN: opt < %s -passes='cgscc(coro-split),simplifycfg,early-cse' -S | FileCheck %s
define ptr @f(i1 %n) presplitcoroutine {
; CHECK-LABEL: define ptr @f(
; CHECK-SAME: i1 [[N:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[ID:%.*]] = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr @f.resumers)
; CHECK-NEXT: [[MEM:%.*]] = call ptr @malloc(i32 56)
; CHECK-NEXT: [[HDL:%.*]] = call noalias nonnull ptr @llvm.coro.begin(token [[ID]], ptr [[MEM]])
; CHECK-NEXT: store ptr @f.resume, ptr [[HDL]], align 8
; CHECK-NEXT: [[DESTROY_ADDR:%.*]] = getelementptr inbounds nuw [[F_FRAME:%.*]], ptr [[HDL]], i32 0, i32 1
; CHECK-NEXT: store ptr @f.destroy, ptr [[DESTROY_ADDR]], align 8
; CHECK-NEXT: [[X_RELOAD_ADDR:%.*]] = getelementptr inbounds [[F_FRAME]], ptr [[HDL]], i32 0, i32 2
; CHECK-NEXT: [[ALIAS_SPILL_ADDR:%.*]] = getelementptr inbounds [[F_FRAME]], ptr [[HDL]], i32 0, i32 3
; CHECK-NEXT: store i64 0, ptr [[X_RELOAD_ADDR]], align 4
; CHECK-NEXT: store i64 0, ptr [[ALIAS_SPILL_ADDR]], align 4
; CHECK-NEXT: [[X_ALIAS:%.*]] = insertvalue [1 x ptr] poison, ptr [[X_RELOAD_ADDR]], 0
; CHECK-NEXT: [[X_ALIAS_SPILL_ADDR:%.*]] = getelementptr inbounds [[F_FRAME]], ptr [[HDL]], i32 0, i32 4
; CHECK-NEXT: store [1 x ptr] [[X_ALIAS]], ptr [[X_ALIAS_SPILL_ADDR]], align 8
; CHECK-NEXT: [[Y_ALIAS:%.*]] = insertelement <1 x ptr> poison, ptr [[ALIAS_SPILL_ADDR]], i32 0
; CHECK-NEXT: [[Y_ALIAS_SPILL_ADDR:%.*]] = getelementptr inbounds [[F_FRAME]], ptr [[HDL]], i32 0, i32 5
; CHECK-NEXT: store <1 x ptr> [[Y_ALIAS]], ptr [[Y_ALIAS_SPILL_ADDR]], align 8
; CHECK-NEXT: [[INDEX_ADDR1:%.*]] = getelementptr inbounds nuw [[F_FRAME]], ptr [[HDL]], i32 0, i32 6
; CHECK-NEXT: store i1 false, ptr [[INDEX_ADDR1]], align 1
; CHECK-NEXT: ret ptr [[HDL]]
;
entry:
%x = alloca i64
%y = alloca i64
%id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
%size = call i32 @llvm.coro.size.i32()
%mem = call ptr @malloc(i32 %size)
%hdl = call ptr @llvm.coro.begin(token %id, ptr %mem)
store i64 0, ptr %x
store i64 0, ptr %y
%x.alias = insertvalue [1 x ptr] poison, ptr %x, 0
%y.alias = insertelement <1 x ptr> poison, ptr %y, i32 0
%sp1 = call i8 @llvm.coro.suspend(token none, i1 false)
switch i8 %sp1, label %suspend [i8 0, label %resume
i8 1, label %cleanup]
resume:
call void @use1([1 x ptr] %x.alias)
call void @use2(<1 x ptr> %y.alias)
br label %cleanup
cleanup:
%mem1 = call ptr @llvm.coro.free(token %id, ptr %hdl)
call void @free(ptr %mem1)
br label %suspend
suspend:
call i1 @llvm.coro.end(ptr %hdl, i1 0, token none)
ret ptr %hdl
}
declare void @use1([1 x ptr])
declare void @use2(<1 x ptr>)
declare noalias ptr @malloc(i32)
declare void @free(ptr)