Skip to content

llvm-reduce: Do not reduce alloca array sizes to 0 #132864

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
arsenm merged 1 commit into from
Apr 2, 2025
Merged

llvm-reduce: Do not reduce alloca array sizes to 0 #132864

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
69 changes: 69 additions & 0 deletions llvm/test/tools/llvm-reduce/reduce-operands-alloca.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,69 @@
; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=operands-zero --test FileCheck --test-arg --check-prefix=CHECK --test-arg %s --test-arg --input-file %s -o %t
; RUN: FileCheck %s --check-prefixes=CHECK,ZERO < %t

; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=operands-one --test FileCheck --test-arg --check-prefix=CHECK --test-arg %s --test-arg --input-file %s -o %t
; RUN: FileCheck %s --check-prefixes=CHECK,ONE < %t

; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=operands-poison --test FileCheck --test-arg --check-prefix=CHECK --test-arg %s --test-arg --input-file %s -o %t
; RUN: FileCheck %s --check-prefixes=CHECK,POISON < %t


; CHECK-LABEL: @dyn_alloca(
; ZERO: %alloca = alloca i32, i32 %size, align 4
; ONE: %alloca = alloca i32, align 4
; POISON: %alloca = alloca i32, i32 %size, align 4
define void @dyn_alloca(i32 %size) {
%alloca = alloca i32, i32 %size
store i32 0, ptr %alloca
ret void
}

; CHECK-LABEL: @alloca_0_elt(
; ZERO: %alloca = alloca i32, i32 0, align 4
; ONE: %alloca = alloca i32, i32 0, align 4
; POISON: %alloca = alloca i32, i32 0, align 4
define void @alloca_0_elt() {
%alloca = alloca i32, i32 0
store i32 0, ptr %alloca
ret void
}

; CHECK-LABEL: @alloca_1_elt(
; ZERO: %alloca = alloca i32, align 4
; ONE: %alloca = alloca i32, align 4
; POISON: %alloca = alloca i32, align 4
define void @alloca_1_elt() {
%alloca = alloca i32, i32 1
store i32 0, ptr %alloca
ret void
}

; CHECK-LABEL: @alloca_1024_elt(
; ZERO: %alloca = alloca i32, i32 1024, align 4
; ONE: %alloca = alloca i32, align 4
; POISON: %alloca = alloca i32, i32 1024, align 4
define void @alloca_1024_elt() {
%alloca = alloca i32, i32 1024
store i32 0, ptr %alloca
ret void
}

; CHECK-LABEL: @alloca_poison_elt(
; ZERO: %alloca = alloca i32, i32 poison, align 4
; ONE: %alloca = alloca i32, align 4
; POISON: %alloca = alloca i32, i32 poison, align 4
define void @alloca_poison_elt() {
%alloca = alloca i32, i32 poison
store i32 0, ptr %alloca
ret void
}

; CHECK-LABEL: @alloca_constexpr_elt(
; ZERO: %alloca = alloca i32, i32 ptrtoint (ptr @alloca_constexpr_elt to i32)
; ONE: %alloca = alloca i32, align 4
; POISON: %alloca = alloca i32, i32 ptrtoint (ptr @alloca_constexpr_elt to i32)
define void @alloca_constexpr_elt() {
%alloca = alloca i32, i32 ptrtoint (ptr @alloca_constexpr_elt to i32)
store i32 0, ptr %alloca
ret void
}
5 changes: 5 additions & 0 deletions llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,11 @@ void llvm::reduceOperandsZeroDeltaPass(Oracle &O, ReducerWorkItem &WorkItem) {
auto ReduceValue = [](Use &Op) -> Value * {
if (!shouldReduceOperand(Op))
return nullptr;

// Avoid introducing 0-sized allocations.
if (isa<AllocaInst>(Op.getUser()))
return nullptr;

// Don't duplicate an existing switch case.
if (auto *IntTy = dyn_cast<IntegerType>(Op->getType()))
if (switchCaseExists(Op, ConstantInt::get(IntTy, 0)))
Expand Down
Loading