[llvm] 8848258 - [SROA] Unfold gep of index phi (round 2) (#83494)
via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 4 14:21:30 PST 2024
Author: Arthur Eubanks
Date: 2024-03-04T14:21:26-08:00
New Revision: 8848258f7bf67fbaf49213a2fb7edb8a3c2f0493
URL: https://github.com/llvm/llvm-project/commit/8848258f7bf67fbaf49213a2fb7edb8a3c2f0493
DIFF: https://github.com/llvm/llvm-project/commit/8848258f7bf67fbaf49213a2fb7edb8a3c2f0493.diff
LOG: [SROA] Unfold gep of index phi (round 2) (#83494)
If a gep has only one phi as one of its operands and the remaining
indexes are constant, we can unfold `gep ptr, (phi idx1, idx2)` to `phi
((gep ptr, idx1), (gep ptr, idx2))`.
Take care not to unfold recursive phis.
Followup to #80983.
This was initially was #83087. Initial PR did not handle allocas in
entry block that weren't at the beginning of the function, causing GEPs
to be inserted after the first chunk of allocas but potentially before
an alloca not at the beginning. Insert GEPs at the end of the entry
block instead since constants/arguments/static allocas can all be used
there.
Added:
Modified:
llvm/lib/Transforms/Scalar/SROA.cpp
llvm/test/Transforms/SROA/phi-and-select.ll
llvm/test/Transforms/SROA/phi-gep.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index fad70e8bf2861f..b2de2209b3f199 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -3956,11 +3956,11 @@ class AggLoadStoreRewriter : public InstVisitor<AggLoadStoreRewriter, bool> {
return false;
}
- // Fold gep (select cond, ptr1, ptr2), idx
+ // Unfold gep (select cond, ptr1, ptr2), idx
// => select cond, gep(ptr1, idx), gep(ptr2, idx)
// and gep ptr, (select cond, idx1, idx2)
// => select cond, gep(ptr, idx1), gep(ptr, idx2)
- bool foldGEPSelect(GetElementPtrInst &GEPI) {
+ bool unfoldGEPSelect(GetElementPtrInst &GEPI) {
// Check whether the GEP has exactly one select operand and all indices
// will become constant after the transform.
SelectInst *Sel = dyn_cast<SelectInst>(GEPI.getPointerOperand());
@@ -4029,67 +4029,104 @@ class AggLoadStoreRewriter : public InstVisitor<AggLoadStoreRewriter, bool> {
return true;
}
- // Fold gep (phi ptr1, ptr2) => phi gep(ptr1), gep(ptr2)
- bool foldGEPPhi(GetElementPtrInst &GEPI) {
- if (!GEPI.hasAllConstantIndices())
- return false;
+ // Unfold gep (phi ptr1, ptr2), idx
+ // => phi ((gep ptr1, idx), (gep ptr2, idx))
+ // and gep ptr, (phi idx1, idx2)
+ // => phi ((gep ptr, idx1), (gep ptr, idx2))
+ bool unfoldGEPPhi(GetElementPtrInst &GEPI) {
+ // To prevent infinitely expanding recursive phis, bail if the GEP pointer
+ // operand (looking through the phi if it is the phi we want to unfold) is
+ // an instruction besides an alloca.
+ PHINode *Phi = dyn_cast<PHINode>(GEPI.getPointerOperand());
+ auto IsInvalidPointerOperand = [](Value *V) {
+ return isa<Instruction>(V) && !isa<AllocaInst>(V);
+ };
+ if (Phi) {
+ if (any_of(Phi->operands(), IsInvalidPointerOperand))
+ return false;
+ } else {
+ if (IsInvalidPointerOperand(GEPI.getPointerOperand()))
+ return false;
+ }
+ // Check whether the GEP has exactly one phi operand (including the pointer
+ // operand) and all indices will become constant after the transform.
+ for (Value *Op : GEPI.indices()) {
+ if (auto *SI = dyn_cast<PHINode>(Op)) {
+ if (Phi)
+ return false;
+
+ Phi = SI;
+ if (!all_of(Phi->incoming_values(),
+ [](Value *V) { return isa<ConstantInt>(V); }))
+ return false;
+ continue;
+ }
- PHINode *PHI = cast<PHINode>(GEPI.getPointerOperand());
- if (GEPI.getParent() != PHI->getParent() ||
- llvm::any_of(PHI->incoming_values(), [](Value *In) {
- Instruction *I = dyn_cast<Instruction>(In);
- return !I || isa<GetElementPtrInst>(I) || isa<PHINode>(I) ||
- succ_empty(I->getParent()) ||
- !I->getParent()->isLegalToHoistInto();
- }))
+ if (!isa<ConstantInt>(Op))
+ return false;
+ }
+
+ if (!Phi)
return false;
LLVM_DEBUG(dbgs() << " Rewriting gep(phi) -> phi(gep):\n";
- dbgs() << " original: " << *PHI << "\n";
+ dbgs() << " original: " << *Phi << "\n";
dbgs() << " " << GEPI << "\n";);
- SmallVector<Value *, 4> Index(GEPI.indices());
+ auto GetNewOps = [&](Value *PhiOp) {
+ SmallVector<Value *> NewOps;
+ for (Value *Op : GEPI.operands())
+ if (Op == Phi)
+ NewOps.push_back(PhiOp);
+ else
+ NewOps.push_back(Op);
+ return NewOps;
+ };
+
+ IRB.SetInsertPoint(Phi);
+ PHINode *NewPhi = IRB.CreatePHI(GEPI.getType(), Phi->getNumIncomingValues(),
+ Phi->getName() + ".sroa.phi");
+
bool IsInBounds = GEPI.isInBounds();
- IRB.SetInsertPoint(GEPI.getParent(), GEPI.getParent()->getFirstNonPHIIt());
- PHINode *NewPN = IRB.CreatePHI(GEPI.getType(), PHI->getNumIncomingValues(),
- PHI->getName() + ".sroa.phi");
- for (unsigned I = 0, E = PHI->getNumIncomingValues(); I != E; ++I) {
- BasicBlock *B = PHI->getIncomingBlock(I);
- Value *NewVal = nullptr;
- int Idx = NewPN->getBasicBlockIndex(B);
- if (Idx >= 0) {
- NewVal = NewPN->getIncomingValue(Idx);
+ Type *SourceTy = GEPI.getSourceElementType();
+ // We only handle arguments, constants, and static allocas here, so we can
+ // insert GEPs at the end of the entry block.
+ IRB.SetInsertPoint(GEPI.getFunction()->getEntryBlock().getTerminator());
+ for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
+ Value *Op = Phi->getIncomingValue(I);
+ BasicBlock *BB = Phi->getIncomingBlock(I);
+ Value *NewGEP;
+ if (int NI = NewPhi->getBasicBlockIndex(BB); NI >= 0) {
+ NewGEP = NewPhi->getIncomingValue(NI);
} else {
- Instruction *In = cast<Instruction>(PHI->getIncomingValue(I));
-
- IRB.SetInsertPoint(In->getParent(), std::next(In->getIterator()));
- Type *Ty = GEPI.getSourceElementType();
- NewVal = IRB.CreateGEP(Ty, In, Index, In->getName() + ".sroa.gep",
- IsInBounds);
+ SmallVector<Value *> NewOps = GetNewOps(Op);
+ NewGEP =
+ IRB.CreateGEP(SourceTy, NewOps[0], ArrayRef(NewOps).drop_front(),
+ Phi->getName() + ".sroa.gep", IsInBounds);
}
- NewPN->addIncoming(NewVal, B);
+ NewPhi->addIncoming(NewGEP, BB);
}
Visited.erase(&GEPI);
- GEPI.replaceAllUsesWith(NewPN);
+ GEPI.replaceAllUsesWith(NewPhi);
GEPI.eraseFromParent();
- Visited.insert(NewPN);
- enqueueUsers(*NewPN);
+ Visited.insert(NewPhi);
+ enqueueUsers(*NewPhi);
LLVM_DEBUG(dbgs() << " to: ";
for (Value *In
- : NewPN->incoming_values()) dbgs()
+ : NewPhi->incoming_values()) dbgs()
<< "\n " << *In;
- dbgs() << "\n " << *NewPN << '\n');
+ dbgs() << "\n " << *NewPhi << '\n');
return true;
}
bool visitGetElementPtrInst(GetElementPtrInst &GEPI) {
- if (foldGEPSelect(GEPI))
+ if (unfoldGEPSelect(GEPI))
return true;
- if (isa<PHINode>(GEPI.getPointerOperand()) && foldGEPPhi(GEPI))
+ if (unfoldGEPPhi(GEPI))
return true;
enqueueUsers(GEPI);
diff --git a/llvm/test/Transforms/SROA/phi-and-select.ll b/llvm/test/Transforms/SROA/phi-and-select.ll
index 54cfb10793a1ac..7c8b27c9de9c0b 100644
--- a/llvm/test/Transforms/SROA/phi-and-select.ll
+++ b/llvm/test/Transforms/SROA/phi-and-select.ll
@@ -114,13 +114,13 @@ define i32 @test3(i32 %x) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: entry:
; CHECK-NEXT: switch i32 [[X:%.*]], label [[BB0:%.*]] [
-; CHECK-NEXT: i32 1, label [[BB1:%.*]]
-; CHECK-NEXT: i32 2, label [[BB2:%.*]]
-; CHECK-NEXT: i32 3, label [[BB3:%.*]]
-; CHECK-NEXT: i32 4, label [[BB4:%.*]]
-; CHECK-NEXT: i32 5, label [[BB5:%.*]]
-; CHECK-NEXT: i32 6, label [[BB6:%.*]]
-; CHECK-NEXT: i32 7, label [[BB7:%.*]]
+; CHECK-NEXT: i32 1, label [[BB1:%.*]]
+; CHECK-NEXT: i32 2, label [[BB2:%.*]]
+; CHECK-NEXT: i32 3, label [[BB3:%.*]]
+; CHECK-NEXT: i32 4, label [[BB4:%.*]]
+; CHECK-NEXT: i32 5, label [[BB5:%.*]]
+; CHECK-NEXT: i32 6, label [[BB6:%.*]]
+; CHECK-NEXT: i32 7, label [[BB7:%.*]]
; CHECK-NEXT: ]
; CHECK: bb0:
; CHECK-NEXT: br label [[EXIT:%.*]]
@@ -733,6 +733,7 @@ define void @PR20822(i1 %c1, i1 %c2, ptr %ptr) {
; CHECK-LABEL: @PR20822(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[F_SROA_0:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[F1_SROA_GEP:%.*]] = getelementptr inbounds [[STRUCT_S:%.*]], ptr [[PTR:%.*]], i32 0, i32 0
; CHECK-NEXT: br i1 [[C1:%.*]], label [[IF_END:%.*]], label [[FOR_COND:%.*]]
; CHECK: for.cond:
; CHECK-NEXT: br label [[IF_END]]
@@ -742,9 +743,8 @@ define void @PR20822(i1 %c1, i1 %c2, ptr %ptr) {
; CHECK: if.then2:
; CHECK-NEXT: br label [[IF_THEN5]]
; CHECK: if.then5:
-; CHECK-NEXT: [[F1:%.*]] = phi ptr [ [[PTR:%.*]], [[IF_THEN2]] ], [ [[F_SROA_0]], [[IF_END]] ]
-; CHECK-NEXT: [[DOTFCA_0_GEP:%.*]] = getelementptr inbounds [[STRUCT_S:%.*]], ptr [[F1]], i32 0, i32 0
-; CHECK-NEXT: store i32 0, ptr [[DOTFCA_0_GEP]], align 4
+; CHECK-NEXT: [[F1_SROA_PHI:%.*]] = phi ptr [ [[F1_SROA_GEP]], [[IF_THEN2]] ], [ [[F_SROA_0]], [[IF_END]] ]
+; CHECK-NEXT: store i32 0, ptr [[F1_SROA_PHI]], align 4
; CHECK-NEXT: ret void
;
entry:
diff --git a/llvm/test/Transforms/SROA/phi-gep.ll b/llvm/test/Transforms/SROA/phi-gep.ll
index c5aa1cdd9cf654..33f42af69608a7 100644
--- a/llvm/test/Transforms/SROA/phi-gep.ll
+++ b/llvm/test/Transforms/SROA/phi-gep.ll
@@ -65,15 +65,13 @@ end:
define i32 @test_sroa_phi_gep_poison(i1 %cond) {
; CHECK-LABEL: @test_sroa_phi_gep_poison(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[A:%.*]] = alloca [[PAIR:%.*]], align 4
; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_THEN:%.*]], label [[END:%.*]]
; CHECK: if.then:
+; CHECK-NEXT: [[PHI_SROA_PHI_SROA_SPECULATE_LOAD_IF_THEN:%.*]] = load i32, ptr poison, align 4
; CHECK-NEXT: br label [[END]]
; CHECK: end:
-; CHECK-NEXT: [[PHI:%.*]] = phi ptr [ [[A]], [[ENTRY:%.*]] ], [ poison, [[IF_THEN]] ]
-; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds [[PAIR]], ptr [[PHI]], i32 0, i32 1
-; CHECK-NEXT: [[LOAD:%.*]] = load i32, ptr [[GEP]], align 4
-; CHECK-NEXT: ret i32 [[LOAD]]
+; CHECK-NEXT: [[PHI_SROA_PHI_SROA_SPECULATED:%.*]] = phi i32 [ undef, [[ENTRY:%.*]] ], [ [[PHI_SROA_PHI_SROA_SPECULATE_LOAD_IF_THEN]], [[IF_THEN]] ]
+; CHECK-NEXT: ret i32 [[PHI_SROA_PHI_SROA_SPECULATED]]
;
entry:
%a = alloca %pair, align 4
@@ -94,17 +92,13 @@ end:
define i32 @test_sroa_phi_gep_global(i1 %cond) {
; CHECK-LABEL: @test_sroa_phi_gep_global(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[A:%.*]] = alloca [[PAIR:%.*]], align 4
-; CHECK-NEXT: [[GEP_A:%.*]] = getelementptr inbounds [[PAIR]], ptr [[A]], i32 0, i32 1
-; CHECK-NEXT: store i32 1, ptr [[GEP_A]], align 4
; CHECK-NEXT: br i1 [[COND:%.*]], label [[IF_THEN:%.*]], label [[END:%.*]]
; CHECK: if.then:
+; CHECK-NEXT: [[PHI_SROA_PHI_SROA_SPECULATE_LOAD_IF_THEN:%.*]] = load i32, ptr getelementptr inbounds ([[PAIR:%.*]], ptr @g, i32 0, i32 1), align 4
; CHECK-NEXT: br label [[END]]
; CHECK: end:
-; CHECK-NEXT: [[PHI:%.*]] = phi ptr [ [[A]], [[ENTRY:%.*]] ], [ @g, [[IF_THEN]] ]
-; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds [[PAIR]], ptr [[PHI]], i32 0, i32 1
-; CHECK-NEXT: [[LOAD:%.*]] = load i32, ptr [[GEP]], align 4
-; CHECK-NEXT: ret i32 [[LOAD]]
+; CHECK-NEXT: [[PHI_SROA_PHI_SROA_SPECULATED:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[PHI_SROA_PHI_SROA_SPECULATE_LOAD_IF_THEN]], [[IF_THEN]] ]
+; CHECK-NEXT: ret i32 [[PHI_SROA_PHI_SROA_SPECULATED]]
;
entry:
%a = alloca %pair, align 4
@@ -245,7 +239,7 @@ define i32 @test_sroa_invoke_phi_gep(i1 %cond) personality ptr @__gxx_personalit
; CHECK-NEXT: br i1 [[COND:%.*]], label [[CALL:%.*]], label [[END:%.*]]
; CHECK: call:
; CHECK-NEXT: [[B:%.*]] = invoke ptr @foo()
-; CHECK-NEXT: to label [[END]] unwind label [[INVOKE_CATCH:%.*]]
+; CHECK-NEXT: to label [[END]] unwind label [[INVOKE_CATCH:%.*]]
; CHECK: end:
; CHECK-NEXT: [[PHI:%.*]] = phi ptr [ [[A]], [[ENTRY:%.*]] ], [ [[B]], [[CALL]] ]
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds [[PAIR]], ptr [[PHI]], i32 0, i32 1
@@ -253,7 +247,7 @@ define i32 @test_sroa_invoke_phi_gep(i1 %cond) personality ptr @__gxx_personalit
; CHECK-NEXT: ret i32 [[LOAD]]
; CHECK: invoke_catch:
; CHECK-NEXT: [[RES:%.*]] = landingpad { ptr, i32 }
-; CHECK-NEXT: catch ptr null
+; CHECK-NEXT: catch ptr null
; CHECK-NEXT: ret i32 0
;
entry:
@@ -468,10 +462,10 @@ define i32 @test_sroa_phi_gep_multiple_values_from_same_block(i32 %arg) {
; CHECK-LABEL: @test_sroa_phi_gep_multiple_values_from_same_block(
; CHECK-NEXT: bb.1:
; CHECK-NEXT: switch i32 [[ARG:%.*]], label [[BB_3:%.*]] [
-; CHECK-NEXT: i32 1, label [[BB_2:%.*]]
-; CHECK-NEXT: i32 2, label [[BB_2]]
-; CHECK-NEXT: i32 3, label [[BB_4:%.*]]
-; CHECK-NEXT: i32 4, label [[BB_4]]
+; CHECK-NEXT: i32 1, label [[BB_2:%.*]]
+; CHECK-NEXT: i32 2, label [[BB_2]]
+; CHECK-NEXT: i32 3, label [[BB_4:%.*]]
+; CHECK-NEXT: i32 4, label [[BB_4]]
; CHECK-NEXT: ]
; CHECK: bb.2:
; CHECK-NEXT: br label [[BB_4]]
@@ -504,6 +498,186 @@ bb.4: ; preds = %bb.1, %bb.1, %bb
ret i32 %load
}
+define i64 @test_phi_idx_mem2reg_const(i1 %arg) {
+; CHECK-LABEL: @test_phi_idx_mem2reg_const(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[BB1:%.*]], label [[BB2:%.*]]
+; CHECK: bb1:
+; CHECK-NEXT: br label [[END:%.*]]
+; CHECK: bb2:
+; CHECK-NEXT: br label [[END]]
+; CHECK: end:
+; CHECK-NEXT: [[PHI_SROA_PHI_SROA_SPECULATED:%.*]] = phi i64 [ 2, [[BB1]] ], [ 3, [[BB2]] ]
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 0, [[BB1]] ], [ 1, [[BB2]] ]
+; CHECK-NEXT: ret i64 [[PHI_SROA_PHI_SROA_SPECULATED]]
+;
+bb:
+ %alloca = alloca [2 x i64], align 8
+ %gep1 = getelementptr inbounds i64, ptr %alloca, i64 1
+ store i64 2, ptr %alloca
+ store i64 3, ptr %gep1
+ br i1 %arg, label %bb1, label %bb2
+
+bb1:
+ br label %end
+
+bb2:
+ br label %end
+
+end:
+ %phi = phi i64 [ 0, %bb1 ], [ 1, %bb2 ]
+ %getelementptr = getelementptr inbounds i64, ptr %alloca, i64 %phi
+ %load = load i64, ptr %getelementptr
+ ret i64 %load
+}
+
+define i64 @test_phi_idx_mem2reg_not_const(i1 %arg, i64 %idx) {
+; CHECK-LABEL: @test_phi_idx_mem2reg_not_const(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [2 x i64], align 8
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr inbounds i64, ptr [[ALLOCA]], i64 1
+; CHECK-NEXT: store i64 2, ptr [[ALLOCA]], align 4
+; CHECK-NEXT: store i64 3, ptr [[GEP1]], align 4
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[BB1:%.*]], label [[BB2:%.*]]
+; CHECK: bb1:
+; CHECK-NEXT: br label [[END:%.*]]
+; CHECK: bb2:
+; CHECK-NEXT: br label [[END]]
+; CHECK: end:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 0, [[BB1]] ], [ [[IDX:%.*]], [[BB2]] ]
+; CHECK-NEXT: [[GETELEMENTPTR:%.*]] = getelementptr inbounds i64, ptr [[ALLOCA]], i64 [[PHI]]
+; CHECK-NEXT: [[LOAD:%.*]] = load i64, ptr [[GETELEMENTPTR]], align 4
+; CHECK-NEXT: ret i64 [[LOAD]]
+;
+bb:
+ %alloca = alloca [2 x i64], align 8
+ %gep1 = getelementptr inbounds i64, ptr %alloca, i64 1
+ store i64 2, ptr %alloca
+ store i64 3, ptr %gep1
+ br i1 %arg, label %bb1, label %bb2
+
+bb1:
+ br label %end
+
+bb2:
+ br label %end
+
+end:
+ %phi = phi i64 [ 0, %bb1 ], [ %idx, %bb2 ]
+ %getelementptr = getelementptr inbounds i64, ptr %alloca, i64 %phi
+ %load = load i64, ptr %getelementptr
+ ret i64 %load
+}
+
+define i64 @test_phi_mem2reg_pointer_op_is_non_const_gep(i1 %arg, i64 %idx) {
+; CHECK-LABEL: @test_phi_mem2reg_pointer_op_is_non_const_gep(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [2 x i64], align 8
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr inbounds i64, ptr [[ALLOCA]], i64 1
+; CHECK-NEXT: store i64 2, ptr [[ALLOCA]], align 4
+; CHECK-NEXT: store i64 3, ptr [[GEP1]], align 4
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[BB1:%.*]], label [[BB2:%.*]]
+; CHECK: bb1:
+; CHECK-NEXT: br label [[END:%.*]]
+; CHECK: bb2:
+; CHECK-NEXT: br label [[END]]
+; CHECK: end:
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 0, [[BB1]] ], [ 1, [[BB2]] ]
+; CHECK-NEXT: [[GETELEMENTPTR:%.*]] = getelementptr inbounds i64, ptr [[ALLOCA]], i64 [[IDX:%.*]]
+; CHECK-NEXT: [[GETELEMENTPTR2:%.*]] = getelementptr inbounds i64, ptr [[GETELEMENTPTR]], i64 [[PHI]]
+; CHECK-NEXT: [[LOAD:%.*]] = load i64, ptr [[GETELEMENTPTR]], align 4
+; CHECK-NEXT: ret i64 [[LOAD]]
+;
+bb:
+ %alloca = alloca [2 x i64], align 8
+ %gep1 = getelementptr inbounds i64, ptr %alloca, i64 1
+ store i64 2, ptr %alloca
+ store i64 3, ptr %gep1
+ br i1 %arg, label %bb1, label %bb2
+
+bb1:
+ br label %end
+
+bb2:
+ br label %end
+
+end:
+ %phi = phi i64 [ 0, %bb1 ], [ 1, %bb2 ]
+ %getelementptr = getelementptr inbounds i64, ptr %alloca, i64 %idx
+ %getelementptr2 = getelementptr inbounds i64, ptr %getelementptr, i64 %phi
+ %load = load i64, ptr %getelementptr
+ ret i64 %load
+}
+
+define i1 @test_phi_mem2reg_entry_block_alloca_not_at_beginning(i1 %arg) {
+; CHECK-LABEL: @test_phi_mem2reg_entry_block_alloca_not_at_beginning(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: call void @f()
+; CHECK-NEXT: [[ALLOCA:%.*]] = alloca i64, align 8
+; CHECK-NEXT: [[PHI_SROA_GEP:%.*]] = getelementptr i64, ptr [[ALLOCA]], i64 1
+; CHECK-NEXT: [[PHI_SROA_GEP1:%.*]] = getelementptr i64, ptr [[ALLOCA]], i64 2
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[BB2:%.*]], label [[BB3:%.*]]
+; CHECK: bb2:
+; CHECK-NEXT: br label [[BB3]]
+; CHECK: bb3:
+; CHECK-NEXT: [[PHI_SROA_PHI:%.*]] = phi ptr [ [[PHI_SROA_GEP]], [[BB:%.*]] ], [ [[PHI_SROA_GEP1]], [[BB2]] ]
+; CHECK-NEXT: [[PHI:%.*]] = phi i64 [ 1, [[BB]] ], [ 2, [[BB2]] ]
+; CHECK-NEXT: [[ICMP:%.*]] = icmp eq ptr [[PHI_SROA_PHI]], null
+; CHECK-NEXT: ret i1 [[ICMP]]
+;
+bb:
+ call void @f()
+ %alloca = alloca i64
+ br i1 %arg, label %bb2, label %bb3
+bb2:
+ br label %bb3
+bb3:
+ %phi = phi i64 [ 1, %bb ], [ 2, %bb2 ]
+ %gep = getelementptr i64, ptr %alloca, i64 %phi
+ %icmp = icmp eq ptr %gep, null
+ ret i1 %icmp
+}
+
+define i64 @test_unfold_phi_duplicate_phi_entry(ptr %arg, i8 %arg1, i1 %arg2) {
+; CHECK-LABEL: @test_unfold_phi_duplicate_phi_entry(
+; CHECK-NEXT: bb:
+; CHECK-NEXT: [[ALLOCA_SROA_0:%.*]] = alloca i64, align 8
+; CHECK-NEXT: [[PHI_SROA_GEP:%.*]] = getelementptr i64, ptr [[ARG:%.*]], i64 1
+; CHECK-NEXT: br i1 [[ARG2:%.*]], label [[BB5:%.*]], label [[BB3:%.*]]
+; CHECK: bb3:
+; CHECK-NEXT: switch i8 [[ARG1:%.*]], label [[BB4:%.*]] [
+; CHECK-NEXT: i8 0, label [[BB5]]
+; CHECK-NEXT: i8 1, label [[BB5]]
+; CHECK-NEXT: ]
+; CHECK: bb4:
+; CHECK-NEXT: ret i64 0
+; CHECK: bb5:
+; CHECK-NEXT: [[PHI_SROA_PHI:%.*]] = phi ptr [ [[PHI_SROA_GEP]], [[BB3]] ], [ [[PHI_SROA_GEP]], [[BB3]] ], [ [[ALLOCA_SROA_0]], [[BB:%.*]] ]
+; CHECK-NEXT: [[LOAD:%.*]] = load i64, ptr [[PHI_SROA_PHI]], align 4
+; CHECK-NEXT: ret i64 [[LOAD]]
+;
+bb:
+ %alloca = alloca [2 x i64], align 8
+ br i1 %arg2, label %bb5, label %bb3
+
+bb3: ; preds = %bb
+ switch i8 %arg1, label %bb4 [
+ i8 0, label %bb5
+ i8 1, label %bb5
+ ]
+
+bb4: ; preds = %bb5, %bb3
+ ret i64 0
+
+bb5: ; preds = %bb3, %bb3, %bb
+ %phi = phi ptr [ %arg, %bb3 ], [ %arg, %bb3 ], [ %alloca, %bb ]
+ %getelementptr = getelementptr i64, ptr %phi, i64 1
+ %load = load i64, ptr %getelementptr
+ ret i64 %load
+}
+
+declare void @f()
+
declare ptr @foo()
declare i32 @__gxx_personality_v0(...)
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