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-rw-r--r--llvm/lib/Transforms/Coroutines/CoroSplit.cpp98
-rw-r--r--llvm/test/Transforms/Coroutines/coro-split-musttail4.ll65
2 files changed, 128 insertions, 35 deletions
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index b6932dbbfc3f..fc83befe3950 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -29,6 +29,7 @@
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
+#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/LazyCallGraph.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
@@ -1174,6 +1175,15 @@ scanPHIsAndUpdateValueMap(Instruction *Prev, BasicBlock *NewBlock,
static bool simplifyTerminatorLeadingToRet(Instruction *InitialInst) {
DenseMap<Value *, Value *> ResolvedValues;
BasicBlock *UnconditionalSucc = nullptr;
+ assert(InitialInst->getModule());
+ const DataLayout &DL = InitialInst->getModule()->getDataLayout();
+
+ auto TryResolveConstant = [&ResolvedValues](Value *V) {
+ auto It = ResolvedValues.find(V);
+ if (It != ResolvedValues.end())
+ V = It->second;
+ return dyn_cast<ConstantInt>(V);
+ };
Instruction *I = InitialInst;
while (I->isTerminator() ||
@@ -1190,47 +1200,65 @@ static bool simplifyTerminatorLeadingToRet(Instruction *InitialInst) {
}
if (auto *BR = dyn_cast<BranchInst>(I)) {
if (BR->isUnconditional()) {
- BasicBlock *BB = BR->getSuccessor(0);
+ BasicBlock *Succ = BR->getSuccessor(0);
if (I == InitialInst)
- UnconditionalSucc = BB;
- scanPHIsAndUpdateValueMap(I, BB, ResolvedValues);
- I = BB->getFirstNonPHIOrDbgOrLifetime();
+ UnconditionalSucc = Succ;
+ scanPHIsAndUpdateValueMap(I, Succ, ResolvedValues);
+ I = Succ->getFirstNonPHIOrDbgOrLifetime();
+ continue;
+ }
+
+ BasicBlock *BB = BR->getParent();
+ // Handle the case the condition of the conditional branch is constant.
+ // e.g.,
+ //
+ // br i1 false, label %cleanup, label %CoroEnd
+ //
+ // It is possible during the transformation. We could continue the
+ // simplifying in this case.
+ if (ConstantFoldTerminator(BB, /*DeleteDeadConditions=*/true)) {
+ // Handle this branch in next iteration.
+ I = BB->getTerminator();
continue;
}
} else if (auto *CondCmp = dyn_cast<CmpInst>(I)) {
+ // If the case number of suspended switch instruction is reduced to
+ // 1, then it is simplified to CmpInst in llvm::ConstantFoldTerminator.
auto *BR = dyn_cast<BranchInst>(I->getNextNode());
- if (BR && BR->isConditional() && CondCmp == BR->getCondition()) {
- // If the case number of suspended switch instruction is reduced to
- // 1, then it is simplified to CmpInst in llvm::ConstantFoldTerminator.
- // And the comparsion looks like : %cond = icmp eq i8 %V, constant.
- ConstantInt *CondConst = dyn_cast<ConstantInt>(CondCmp->getOperand(1));
- if (CondConst && CondCmp->getPredicate() == CmpInst::ICMP_EQ) {
- Value *V = CondCmp->getOperand(0);
- auto it = ResolvedValues.find(V);
- if (it != ResolvedValues.end())
- V = it->second;
-
- if (ConstantInt *Cond0 = dyn_cast<ConstantInt>(V)) {
- BasicBlock *BB = Cond0->equalsInt(CondConst->getZExtValue())
- ? BR->getSuccessor(0)
- : BR->getSuccessor(1);
- scanPHIsAndUpdateValueMap(I, BB, ResolvedValues);
- I = BB->getFirstNonPHIOrDbgOrLifetime();
- continue;
- }
- }
- }
+ if (!BR || !BR->isConditional() || CondCmp != BR->getCondition())
+ return false;
+
+ // And the comparsion looks like : %cond = icmp eq i8 %V, constant.
+ // So we try to resolve constant for the first operand only since the
+ // second operand should be literal constant by design.
+ ConstantInt *Cond0 = TryResolveConstant(CondCmp->getOperand(0));
+ auto *Cond1 = dyn_cast<ConstantInt>(CondCmp->getOperand(1));
+ if (!Cond0 || !Cond1)
+ return false;
+
+ // Both operands of the CmpInst are Constant. So that we could evaluate
+ // it immediately to get the destination.
+ auto *ConstResult =
+ dyn_cast_or_null<ConstantInt>(ConstantFoldCompareInstOperands(
+ CondCmp->getPredicate(), Cond0, Cond1, DL));
+ if (!ConstResult)
+ return false;
+
+ CondCmp->replaceAllUsesWith(ConstResult);
+ CondCmp->eraseFromParent();
+
+ // Handle this branch in next iteration.
+ I = BR;
+ continue;
} else if (auto *SI = dyn_cast<SwitchInst>(I)) {
- Value *V = SI->getCondition();
- auto it = ResolvedValues.find(V);
- if (it != ResolvedValues.end())
- V = it->second;
- if (ConstantInt *Cond = dyn_cast<ConstantInt>(V)) {
- BasicBlock *BB = SI->findCaseValue(Cond)->getCaseSuccessor();
- scanPHIsAndUpdateValueMap(I, BB, ResolvedValues);
- I = BB->getFirstNonPHIOrDbgOrLifetime();
- continue;
- }
+ ConstantInt *Cond = TryResolveConstant(SI->getCondition());
+ if (!Cond)
+ return false;
+
+ BasicBlock *BB = SI->findCaseValue(Cond)->getCaseSuccessor();
+ scanPHIsAndUpdateValueMap(I, BB, ResolvedValues);
+ I = BB->getFirstNonPHIOrDbgOrLifetime();
+ continue;
}
return false;
}
diff --git a/llvm/test/Transforms/Coroutines/coro-split-musttail4.ll b/llvm/test/Transforms/Coroutines/coro-split-musttail4.ll
new file mode 100644
index 000000000000..0d73d94a93f5
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-split-musttail4.ll
@@ -0,0 +1,65 @@
+; Tests that coro-split will convert a call before coro.suspend to a musttail call
+; while the user of the coro.suspend is a icmpinst.
+; RUN: opt < %s -passes='cgscc(coro-split),simplifycfg,early-cse' -S | FileCheck %s
+
+define void @fakeresume1(i8*) {
+entry:
+ ret void;
+}
+
+define void @f() #0 {
+entry:
+ %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
+ %alloc = call i8* @malloc(i64 16) #3
+ %vFrame = call noalias nonnull i8* @llvm.coro.begin(token %id, i8* %alloc)
+
+ %save = call token @llvm.coro.save(i8* null)
+
+ %init_suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
+ switch i8 %init_suspend, label %coro.end [
+ i8 0, label %await.ready
+ i8 1, label %coro.end
+ ]
+await.ready:
+ %save2 = call token @llvm.coro.save(i8* null)
+
+ call fastcc void @fakeresume1(i8* align 8 null)
+ %suspend = call i8 @llvm.coro.suspend(token %save2, i1 true)
+ %switch = icmp ult i8 %suspend, 2
+ br i1 %switch, label %cleanup, label %coro.end
+
+cleanup:
+ %free.handle = call i8* @llvm.coro.free(token %id, i8* %vFrame)
+ %.not = icmp eq i8* %free.handle, null
+ br i1 %.not, label %coro.end, label %coro.free
+
+coro.free:
+ call void @delete(i8* nonnull %free.handle) #2
+ br label %coro.end
+
+coro.end:
+ call i1 @llvm.coro.end(i8* null, i1 false)
+ ret void
+}
+
+; CHECK-LABEL: @f.resume(
+; CHECK: musttail call fastcc void @fakeresume1(
+; CHECK-NEXT: ret void
+
+declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*) #1
+declare i1 @llvm.coro.alloc(token) #2
+declare i64 @llvm.coro.size.i64() #3
+declare i8* @llvm.coro.begin(token, i8* writeonly) #2
+declare token @llvm.coro.save(i8*) #2
+declare i8* @llvm.coro.frame() #3
+declare i8 @llvm.coro.suspend(token, i1) #2
+declare i8* @llvm.coro.free(token, i8* nocapture readonly) #1
+declare i1 @llvm.coro.end(i8*, i1) #2
+declare i8* @llvm.coro.subfn.addr(i8* nocapture readonly, i8) #1
+declare i8* @malloc(i64)
+declare void @delete(i8* nonnull) #2
+
+attributes #0 = { "coroutine.presplit"="1" }
+attributes #1 = { argmemonly nounwind readonly }
+attributes #2 = { nounwind }
+attributes #3 = { nounwind readnone }
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 21:16:11 +0000