[clang] [flang] [flang] Add support for -finit-local-zero (PR #159788)
via cfe-commits
cfe-commits at lists.llvm.org
Sun Jul 26 06:06:48 PDT 2026
https://github.com/NimishMishra updated https://github.com/llvm/llvm-project/pull/159788
>From 80000310c58c79c9081eb64e00c40c9e4d3ffe73 Mon Sep 17 00:00:00 2001
From: NimishMishra <neelam.nimish at gmail.com>
Date: Tue, 21 Jul 2026 19:16:00 +0530
Subject: [PATCH 1/6] Address review comments
---
clang/include/clang/Options/FlangOptions.td | 4 +-
clang/lib/Driver/ToolChains/Flang.cpp | 2 +-
flang/include/flang/Lower/LoweringOptions.def | 3 +
flang/lib/Frontend/CompilerInvocation.cpp | 5 +
flang/lib/Lower/ConvertVariable.cpp | 91 +++++++++++++++++++
flang/test/Driver/finit-local-zero.f90 | 8 ++
flang/test/Lower/init-local-zero.f90 | 66 ++++++++++++++
7 files changed, 177 insertions(+), 2 deletions(-)
create mode 100644 flang/test/Driver/finit-local-zero.f90
create mode 100644 flang/test/Lower/init-local-zero.f90
diff --git a/clang/include/clang/Options/FlangOptions.td b/clang/include/clang/Options/FlangOptions.td
index bafc063663fe2..79cabe35e9406 100644
--- a/clang/include/clang/Options/FlangOptions.td
+++ b/clang/include/clang/Options/FlangOptions.td
@@ -59,7 +59,9 @@ defm dump_parse_tree : BooleanFFlag<"dump-parse-tree">, Group<gfortran_Group>;
defm external_blas : BooleanFFlag<"external-blas">, Group<gfortran_Group>;
defm f2c : BooleanFFlag<"f2c">, Group<gfortran_Group>;
defm frontend_optimize : BooleanFFlag<"frontend-optimize">, Group<gfortran_Group>;
-defm init_local_zero : BooleanFFlag<"init-local-zero">, Group<gfortran_Group>;
+defm init_local_zero : BooleanFFlag<"init-local-zero">, Group<gfortran_Group>,
+ Visibility<[FlangOption, FC1Option]>, HelpText<"Initialize real, integer, character, logical, and complex variables "
+ "to zero.">;
defm integer_4_integer_8 : BooleanFFlag<"integer-4-integer-8">, Group<gfortran_Group>;
defm max_identifier_length : BooleanFFlag<"max-identifier-length">, Group<gfortran_Group>;
defm module_private : BooleanFFlag<"module-private">, Group<gfortran_Group>;
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index d900037230f20..34452206ed6db 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -263,7 +263,7 @@ void Flang::addCodegenOptions(const ArgList &Args,
options::OPT_fno_ppc_native_vec_elem_order,
options::OPT_fppc_native_vec_elem_order, options::OPT_finit_global_zero,
options::OPT_fno_init_global_zero, options::OPT_frepack_arrays,
- options::OPT_fno_repack_arrays,
+ options::OPT_fno_repack_arrays, options::OPT_finit_local_zero,
options::OPT_frepack_arrays_contiguity_EQ,
options::OPT_fstack_repack_arrays, options::OPT_fno_stack_repack_arrays,
options::OPT_ftime_report, options::OPT_ftime_report_EQ,
diff --git a/flang/include/flang/Lower/LoweringOptions.def b/flang/include/flang/Lower/LoweringOptions.def
index 0b02ffd5a3b22..2b75d579c021e 100644
--- a/flang/include/flang/Lower/LoweringOptions.def
+++ b/flang/include/flang/Lower/LoweringOptions.def
@@ -93,5 +93,8 @@ ENUM_LOWERINGOPT(PreserveUseDebugInfo, unsigned, 1, 0)
/// Portable, Extremum, ExtremeNum). Default: Legacy.
ENUM_LOWERINGOPT(FPMaxminBehavior, Fortran::common::FPMaxminBehavior, 2, 0)
+/// When true, it enables semantics for -finit-local-zero during codegen.
+ENUM_LOWERINGOPT(InitLocalZeroDef, unsigned, 1, 0)
+
#undef LOWERINGOPT
#undef ENUM_LOWERINGOPT
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 79ad08353b64c..32f03215f3469 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1684,6 +1684,11 @@ bool CompilerInvocation::createFromArgs(
else
invoc.loweringOpts.setInitGlobalZero(false);
+ // -finit-local-zero
+ if (args.hasArg(clang::options::OPT_finit_local_zero)) {
+ invoc.loweringOpts.setInitLocalZeroDef(1);
+ }
+
// Preserve all the remark options requested, i.e. -Rpass, -Rpass-missed or
// -Rpass-analysis. This will be used later when processing and outputting the
// remarks generated by LLVM in ExecuteCompilerInvocation.cpp.
diff --git a/flang/lib/Lower/ConvertVariable.cpp b/flang/lib/Lower/ConvertVariable.cpp
index 007b536d97098..607f40e48e133 100644
--- a/flang/lib/Lower/ConvertVariable.cpp
+++ b/flang/lib/Lower/ConvertVariable.cpp
@@ -31,6 +31,7 @@
#include "flang/Optimizer/Builder/FIRBuilder.h"
#include "flang/Optimizer/Builder/HLFIRTools.h"
#include "flang/Optimizer/Builder/IntrinsicCall.h"
+#include "flang/Optimizer/Builder/Runtime/Assign.h"
#include "flang/Optimizer/Builder/Runtime/Derived.h"
#include "flang/Optimizer/Builder/Todo.h"
#include "flang/Optimizer/Dialect/CUF/CUFOps.h"
@@ -1225,6 +1226,54 @@ getSafeRepackAttrs(Fortran::lower::AbstractConverter &converter) {
return attrs.empty() ? mlir::ArrayAttr{} : builder.getArrayAttr(attrs);
}
+// Helper class to encapsulate utilities related to emission of implicit
+// assignments. `Implicit` here implies the assignment does not
+// exist in the Fortran source, but is implicit through definition
+// of one or more flagsets (like -finit-* family of flags).
+// General purpose usage of these utilities outside the
+// scope detailed here is discouraged, and is probably wrong.
+class ImplicitAssignmentGenerator {
+private:
+ bool isInitLocalZeroFlagDefined;
+
+public:
+ ImplicitAssignmentGenerator(bool isInitLocalZeroFlagDefined)
+ : isInitLocalZeroFlagDefined(isInitLocalZeroFlagDefined) {}
+
+ void emitAssignment(Fortran::lower::AbstractConverter &converter,
+ mlir::Location loc, const Fortran::semantics::Symbol &sym,
+ Fortran::lower::SymMap &symMap) {
+ if (isInitLocalZeroFlagDefined) {
+ mlir::Type eleTy = hlfir::getFortranElementType(converter.genType(sym));
+ auto *builder = &converter.getFirOpBuilder();
+
+ if (mlir::isa<fir::CharacterType>(eleTy)) {
+ fir::factory::CharacterExprHelper helper{*builder, loc};
+ fir::CharacterType::KindTy kind =
+ helper.getCharacterType(eleTy).getFKind();
+ mlir::Value zeroCode =
+ builder->createIntegerConstant(loc, builder->getI32Type(), 0);
+ mlir::Value zero = helper.createSingletonFromCode(zeroCode, kind);
+ hlfir::Entity lhs{symMap.lookupSymbol(sym).getAddr()};
+ lhs = hlfir::derefPointersAndAllocatables(loc, *builder, lhs);
+ mlir::Value rhsTmp = builder->createTemporary(loc, zero.getType());
+ builder->create<fir::StoreOp>(loc, zero, rhsTmp);
+ builder->create<hlfir::AssignOp>(loc, rhsTmp, lhs);
+ }
+
+ else if (fir::isa_integer(eleTy) || fir::isa_real(eleTy) ||
+ fir::isa_complex(eleTy) || mlir::isa<fir::LogicalType>(eleTy)) {
+ mlir::Value zero = fir::factory::createZeroValue(*builder, loc, eleTy);
+ hlfir::Entity lhs{symMap.lookupSymbol(sym).getAddr()};
+ lhs = hlfir::derefPointersAndAllocatables(loc, *builder, lhs);
+ mlir::Value rhsTmp = builder->createTemporary(loc, zero.getType());
+ builder->create<fir::StoreOp>(loc, zero, rhsTmp);
+ builder->create<hlfir::AssignOp>(loc, rhsTmp, lhs);
+ }
+ }
+ }
+};
+
/// Instantiate a local variable. Precondition: Each variable will be visited
/// such that if its properties depend on other variables, the variables upon
/// which its properties depend will already have been visited.
@@ -1317,6 +1366,48 @@ static void instantiateLocal(Fortran::lower::AbstractConverter &converter,
Fortran::lower::genUnpackArray(*converterPtr, loc, *varDef, *sym);
});
}
+
+ /// These options do not initialize:
+ /// 1) Any variable already initialized
+ /// 2) objects with the POINTER attribute
+ /// 3) allocatable arrays
+ /// 4) variables that appear in an EQUIVALENCE statement
+
+ auto isEligibleForImplicitAssignment = [&var]() -> bool {
+ if (!var.hasSymbol())
+ return false;
+
+ const Fortran::semantics::Symbol &sym = var.getSymbol();
+ if (const auto *details =
+ sym.detailsIf<Fortran::semantics::ObjectEntityDetails>()) {
+ if (details->init())
+ return false;
+ }
+
+ if (sym.attrs().test(Fortran::semantics::Attr::POINTER))
+ return false;
+
+ if (sym.Rank() > 0 &&
+ sym.attrs().test(Fortran::semantics::Attr::ALLOCATABLE))
+ return false;
+
+ if (Fortran::lower::pft::getDependentVariableList(sym).size() > 1)
+ return false;
+
+ return true;
+ };
+
+ if (isEligibleForImplicitAssignment()) {
+ // Internal state of this class holds only the -finit-* flagsets. Hence
+ // can be reused for different symbols. Also minimizes the number of
+ // calls to `getLoweringOptions()`.
+ static ImplicitAssignmentGenerator implicitAssignmentGenerator{
+ /*isInitLocalZeroFlagDefined=*/converter.getLoweringOptions()
+ .getInitLocalZeroDef() == 1};
+
+ implicitAssignmentGenerator.emitAssignment(
+ converter, converter.getCurrentLocation(), var.getSymbol(), symMap);
+ }
}
//===----------------------------------------------------------------===//
diff --git a/flang/test/Driver/finit-local-zero.f90 b/flang/test/Driver/finit-local-zero.f90
new file mode 100644
index 0000000000000..7dd2612e624ad
--- /dev/null
+++ b/flang/test/Driver/finit-local-zero.f90
@@ -0,0 +1,8 @@
+! Check that the driver passes through -finit-global-zero:
+! RUN: %flang -### -S -finit-local-zero %s -o - 2>&1 | FileCheck %s
+
+! Check that the compiler accepts -finit-local-zero:
+! RUN: %flang_fc1 -emit-hlfir -finit-local-zero %s -o -
+
+
+! CHECK: "-fc1"{{.*}}"-finit-local-zero"
diff --git a/flang/test/Lower/init-local-zero.f90 b/flang/test/Lower/init-local-zero.f90
new file mode 100644
index 0000000000000..61a4d70ad788d
--- /dev/null
+++ b/flang/test/Lower/init-local-zero.f90
@@ -0,0 +1,66 @@
+! RUN: %flang_fc1 -emit-hlfir -finit-local-zero -o - %s | FileCheck %s
+
+
+!CHECK-LABEL: func.func @_QPuninitialized_integer() {
+!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca i32
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca i32 {bindc_name = "x", uniq_name = "_QFuninitialized_integerEx"}
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_integerEx"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+!CHECK: %[[ZERO:.*]] = arith.constant 0 : i32
+!CHECK: fir.store %[[ZERO]] to %[[ZERO_ALLOCA]] : !fir.ref<i32>
+!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<i32>, !fir.ref<i32>
+subroutine uninitialized_integer
+ integer :: x
+end subroutine
+
+!CHECK-LABEL: func.func @_QPuninitialized_real() {
+!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca f32
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca f32 {bindc_name = "x", uniq_name = "_QFuninitialized_realEx"}
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_realEx"} : (!fir.ref<f32>) -> (!fir.ref<f32>, !fir.ref<f32>)
+!CHECK: %[[ZERO:.*]] = arith.constant 0.000000e+00 : f32
+!CHECK: fir.store %[[ZERO]] to %[[ZERO_ALLOCA]] : !fir.ref<f32>
+!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<f32>, !fir.ref<f32>
+subroutine uninitialized_real
+ real :: x
+end subroutine
+
+!CHECK-LABEL: func.func @_QPuninitialized_logical() {
+!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca !fir.logical<4>
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca !fir.logical<4> {bindc_name = "x", uniq_name = "_QFuninitialized_logicalEx"}
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_logicalEx"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
+!CHECK: %false = arith.constant false
+!CHECK: %[[CVT:.*]] = fir.convert %false : (i1) -> !fir.logical<4>
+!CHECK: fir.store %[[CVT]] to %[[ZERO_ALLOCA]] : !fir.ref<!fir.logical<4>>
+!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>
+subroutine uninitialized_logical
+ logical :: x
+end subroutine
+
+
+!CHECK-LABEL: func.func @_QPuninitialized_complex() {
+!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca complex<f32>
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca complex<f32> {bindc_name = "x", uniq_name = "_QFuninitialized_complexEx"}
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_complexEx"} : (!fir.ref<complex<f32>>) -> (!fir.ref<complex<f32>>, !fir.ref<complex<f32>>)
+!CHECK: %[[CONST:.*]] = arith.constant 0.000000e+00 : f32
+!CHECK: %[[UNDEF:.*]] = fir.undefined complex<f32>
+!CHECK: %[[IDX0:.*]] = fir.insert_value %[[UNDEF]], %[[CONST]], [0 : index] : (complex<f32>, f32) -> complex<f32>
+!CHECK: %[[IDX1:.*]] = fir.insert_value %[[IDX0]], %[[CONST]], [1 : index] : (complex<f32>, f32) -> complex<f32>
+!CHECK: fir.store %[[IDX1]] to %[[ZERO_ALLOCA]] : !fir.ref<complex<f32>>
+!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<complex<f32>>, !fir.ref<complex<f32>>
+subroutine uninitialized_complex
+ complex :: x
+end subroutine
+
+!CHECK-LABEL: func.func @_QPuninitialized_character() {
+!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca !fir.char<1>
+!CHECK: %[[ONE:.*]] = arith.constant 1 : index
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca !fir.char<1> {bindc_name = "x", uniq_name = "_QFuninitialized_characterEx"}
+!CHECK: %3:2 = hlfir.declare %[[X_ALLOCA]] typeparams %[[ONE]] {uniq_name = "_QFuninitialized_characterEx"} : (!fir.ref<!fir.char<1>>, index) -> (!fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>)
+!CHECK: %[[CONST:.*]] = arith.constant 0 : i32
+!CHECK: %[[CVT:.*]] = fir.convert %[[CONST]] : (i32) -> i8
+!CHECK: %[[UNDEF:.*]] = fir.undefined !fir.char<1>
+!CHECK: %[[VAL:.*]] = fir.insert_value %[[UNDEF]], %[[CVT]], [0 : index] : (!fir.char<1>, i8) -> !fir.char<1>
+!CHECK: fir.store %[[VAL]] to %[[ZERO_ALLOCA]] : !fir.ref<!fir.char<1>>
+!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>
+subroutine uninitialized_character
+ character :: x
+end subroutine
>From a5f6b3cde11ec8ee5c1ae53b7629f91b784ceede Mon Sep 17 00:00:00 2001
From: NimishMishra <neelam.nimish at gmail.com>
Date: Tue, 21 Jul 2026 19:19:51 +0530
Subject: [PATCH 2/6] fix test
---
flang/test/Driver/finit-local-zero.f90 | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/flang/test/Driver/finit-local-zero.f90 b/flang/test/Driver/finit-local-zero.f90
index 7dd2612e624ad..8cfadc9372edc 100644
--- a/flang/test/Driver/finit-local-zero.f90
+++ b/flang/test/Driver/finit-local-zero.f90
@@ -1,8 +1,7 @@
-! Check that the driver passes through -finit-global-zero:
+! Check that the driver passes through -finit-local-zero:
! RUN: %flang -### -S -finit-local-zero %s -o - 2>&1 | FileCheck %s
! Check that the compiler accepts -finit-local-zero:
-! RUN: %flang_fc1 -emit-hlfir -finit-local-zero %s -o -
-
+! RUN: %flang_fc1 -emit-hlfir -finit-local-zero %s -o /dev/null
! CHECK: "-fc1"{{.*}}"-finit-local-zero"
>From 1ad6500f8025ebcb4109469a38f95a83537ce0a5 Mon Sep 17 00:00:00 2001
From: NimishMishra <42909663+NimishMishra at users.noreply.github.com>
Date: Tue, 21 Jul 2026 19:28:04 +0530
Subject: [PATCH 3/6] Update LoweringOptions.def
---
flang/include/flang/Lower/LoweringOptions.def | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/flang/include/flang/Lower/LoweringOptions.def b/flang/include/flang/Lower/LoweringOptions.def
index 2b75d579c021e..3155cf7878608 100644
--- a/flang/include/flang/Lower/LoweringOptions.def
+++ b/flang/include/flang/Lower/LoweringOptions.def
@@ -93,7 +93,7 @@ ENUM_LOWERINGOPT(PreserveUseDebugInfo, unsigned, 1, 0)
/// Portable, Extremum, ExtremeNum). Default: Legacy.
ENUM_LOWERINGOPT(FPMaxminBehavior, Fortran::common::FPMaxminBehavior, 2, 0)
-/// When true, it enables semantics for -finit-local-zero during codegen.
+/// When true, enables semantics for -finit-local-zero during codegen.
ENUM_LOWERINGOPT(InitLocalZeroDef, unsigned, 1, 0)
#undef LOWERINGOPT
>From 02e4431915267f05fa6b988d10a3c05c20503f0d Mon Sep 17 00:00:00 2001
From: NimishMishra <42909663+NimishMishra at users.noreply.github.com>
Date: Tue, 21 Jul 2026 19:29:30 +0530
Subject: [PATCH 4/6] Update CompilerInvocation.cpp
---
flang/lib/Frontend/CompilerInvocation.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 32f03215f3469..903818824a266 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1685,9 +1685,8 @@ bool CompilerInvocation::createFromArgs(
invoc.loweringOpts.setInitGlobalZero(false);
// -finit-local-zero
- if (args.hasArg(clang::options::OPT_finit_local_zero)) {
+ if (args.hasArg(clang::options::OPT_finit_local_zero))
invoc.loweringOpts.setInitLocalZeroDef(1);
- }
// Preserve all the remark options requested, i.e. -Rpass, -Rpass-missed or
// -Rpass-analysis. This will be used later when processing and outputting the
>From ec112fef380534224585cdb88d1fb9d230960e69 Mon Sep 17 00:00:00 2001
From: NimishMishra <neelam.nimish at gmail.com>
Date: Sun, 26 Jul 2026 18:33:53 +0530
Subject: [PATCH 5/6] Address review comments
---
flang/lib/Lower/ConvertVariable.cpp | 115 ++++++++++++++-----------
flang/test/Driver/finit-local-zero.f90 | 4 +-
flang/test/Lower/init-local-zero.f90 | 45 +++++-----
3 files changed, 93 insertions(+), 71 deletions(-)
diff --git a/flang/lib/Lower/ConvertVariable.cpp b/flang/lib/Lower/ConvertVariable.cpp
index 607f40e48e133..8278340f3b7d2 100644
--- a/flang/lib/Lower/ConvertVariable.cpp
+++ b/flang/lib/Lower/ConvertVariable.cpp
@@ -1226,53 +1226,68 @@ getSafeRepackAttrs(Fortran::lower::AbstractConverter &converter) {
return attrs.empty() ? mlir::ArrayAttr{} : builder.getArrayAttr(attrs);
}
-// Helper class to encapsulate utilities related to emission of implicit
+// Helper function to related to emission of implicit
// assignments. `Implicit` here implies the assignment does not
// exist in the Fortran source, but is implicit through definition
// of one or more flagsets (like -finit-* family of flags).
-// General purpose usage of these utilities outside the
+// General purpose usage of this function outside the
// scope detailed here is discouraged, and is probably wrong.
-class ImplicitAssignmentGenerator {
-private:
- bool isInitLocalZeroFlagDefined;
-
-public:
- ImplicitAssignmentGenerator(bool isInitLocalZeroFlagDefined)
- : isInitLocalZeroFlagDefined(isInitLocalZeroFlagDefined) {}
-
- void emitAssignment(Fortran::lower::AbstractConverter &converter,
- mlir::Location loc, const Fortran::semantics::Symbol &sym,
- Fortran::lower::SymMap &symMap) {
- if (isInitLocalZeroFlagDefined) {
- mlir::Type eleTy = hlfir::getFortranElementType(converter.genType(sym));
- auto *builder = &converter.getFirOpBuilder();
-
- if (mlir::isa<fir::CharacterType>(eleTy)) {
- fir::factory::CharacterExprHelper helper{*builder, loc};
- fir::CharacterType::KindTy kind =
- helper.getCharacterType(eleTy).getFKind();
- mlir::Value zeroCode =
- builder->createIntegerConstant(loc, builder->getI32Type(), 0);
- mlir::Value zero = helper.createSingletonFromCode(zeroCode, kind);
- hlfir::Entity lhs{symMap.lookupSymbol(sym).getAddr()};
- lhs = hlfir::derefPointersAndAllocatables(loc, *builder, lhs);
- mlir::Value rhsTmp = builder->createTemporary(loc, zero.getType());
- builder->create<fir::StoreOp>(loc, zero, rhsTmp);
- builder->create<hlfir::AssignOp>(loc, rhsTmp, lhs);
- }
+static void emitImplicitAssignment(Fortran::lower::AbstractConverter &converter,
+ mlir::Location loc,
+ const Fortran::semantics::Symbol &sym,
+ Fortran::lower::SymMap &symMap) {
+ if (converter.getLoweringOptions().getInitLocalZeroDef()) {
+ mlir::Type eleTy = hlfir::getFortranElementType(converter.genType(sym));
+ auto *builder = &converter.getFirOpBuilder();
+
+ if (mlir::isa<fir::CharacterType>(eleTy)) {
+ fir::ExtendedValue ext = converter.getSymbolExtendedValue(sym);
+ const auto *charBox = ext.getCharBox();
+ mlir::Value buffer = charBox->getBuffer();
+ assert(buffer && "CharBox buffer is null");
+ auto eleTy = fir::unwrapRefType(buffer.getType());
+ auto charTy =
+ mlir::cast<fir::CharacterType>(fir::unwrapSequenceType(eleTy));
+ unsigned kindBytes =
+ builder->getKindMap().getCharacterBitsize(charTy.getFKind()) / 8;
+ auto lenVal = charBox->getLen();
+ mlir::Value byteLen;
+ if (lenVal) {
+
+ mlir::Value lenI64 =
+ builder->createConvert(loc, builder->getI64Type(), lenVal);
+ mlir::Value kind = builder->createIntegerConstant(
+ loc, builder->getI64Type(), kindBytes);
+ byteLen = mlir::arith::MulIOp::create(*builder, loc, lenI64, kind);
+ byteLen = builder->createConvert(loc, builder->getI64Type(), byteLen);
+ } else {
- else if (fir::isa_integer(eleTy) || fir::isa_real(eleTy) ||
- fir::isa_complex(eleTy) || mlir::isa<fir::LogicalType>(eleTy)) {
- mlir::Value zero = fir::factory::createZeroValue(*builder, loc, eleTy);
- hlfir::Entity lhs{symMap.lookupSymbol(sym).getAddr()};
- lhs = hlfir::derefPointersAndAllocatables(loc, *builder, lhs);
- mlir::Value rhsTmp = builder->createTemporary(loc, zero.getType());
- builder->create<fir::StoreOp>(loc, zero, rhsTmp);
- builder->create<hlfir::AssignOp>(loc, rhsTmp, lhs);
+ assert(charTy.hasConstantLen() && "expected constant character length");
+ byteLen = builder->createIntegerConstant(loc, builder->getI64Type(),
+ charTy.getLen() * kindBytes);
}
+
+ auto ptrTy = mlir::LLVM::LLVMPointerType::get(builder->getContext());
+ mlir::Value ptr = builder->createConvert(loc, ptrTy, buffer);
+ mlir::Value zero =
+ builder->createIntegerConstant(loc, builder->getI8Type(), 0);
+ mlir::ModuleOp mod = builder->getModule();
+ mlir::OpBuilder modBuilder(mod.getBodyRegion());
+ modBuilder.setInsertionPointToEnd(zero.getParentBlock());
+ mlir::LLVM::MemsetOp::create(
+ modBuilder, loc, ptr, zero, byteLen,
+ fir::isa_volatile_type(converter.genType(sym)));
+ }
+
+ else if (fir::isa_integer(eleTy) || fir::isa_real(eleTy) ||
+ fir::isa_complex(eleTy) || mlir::isa<fir::LogicalType>(eleTy)) {
+ mlir::Value zero = fir::factory::createZeroValue(*builder, loc, eleTy);
+ hlfir::Entity lhs{symMap.lookupSymbol(sym).getAddr()};
+ lhs = hlfir::derefPointersAndAllocatables(loc, *builder, lhs);
+ builder->create<hlfir::AssignOp>(loc, zero, lhs);
}
}
-};
+}
/// Instantiate a local variable. Precondition: Each variable will be visited
/// such that if its properties depend on other variables, the variables upon
@@ -1373,11 +1388,13 @@ static void instantiateLocal(Fortran::lower::AbstractConverter &converter,
/// 3) allocatable arrays
/// 4) variables that appear in an EQUIVALENCE statement
- auto isEligibleForImplicitAssignment = [&var]() -> bool {
+ auto isEligibleForImplicitAssignment = [&var, &converter]() -> bool {
if (!var.hasSymbol())
return false;
const Fortran::semantics::Symbol &sym = var.getSymbol();
+ if (!sym.GetType())
+ return false;
if (const auto *details =
sym.detailsIf<Fortran::semantics::ObjectEntityDetails>()) {
if (details->init())
@@ -1394,19 +1411,19 @@ static void instantiateLocal(Fortran::lower::AbstractConverter &converter,
if (Fortran::lower::pft::getDependentVariableList(sym).size() > 1)
return false;
+ if (auto ty = converter.genType(sym)) {
+ auto charTy =
+ mlir::dyn_cast<fir::CharacterType>(hlfir::getFortranElementType(ty));
+ if (charTy && !charTy.hasConstantLen())
+ return false;
+ }
+
return true;
};
if (isEligibleForImplicitAssignment()) {
- // Internal state of this class holds only the -finit-* flagsets. Hence
- // can be reused for different symbols. Also minimizes the number of
- // calls to `getLoweringOptions()`.
- static ImplicitAssignmentGenerator implicitAssignmentGenerator{
- /*isInitLocalZeroFlagDefined=*/converter.getLoweringOptions()
- .getInitLocalZeroDef() == 1};
-
- implicitAssignmentGenerator.emitAssignment(
- converter, converter.getCurrentLocation(), var.getSymbol(), symMap);
+ emitImplicitAssignment(converter, converter.getCurrentLocation(),
+ var.getSymbol(), symMap);
}
}
diff --git a/flang/test/Driver/finit-local-zero.f90 b/flang/test/Driver/finit-local-zero.f90
index 8cfadc9372edc..b69fe60ba1e70 100644
--- a/flang/test/Driver/finit-local-zero.f90
+++ b/flang/test/Driver/finit-local-zero.f90
@@ -1,7 +1,9 @@
! Check that the driver passes through -finit-local-zero:
! RUN: %flang -### -S -finit-local-zero %s -o - 2>&1 | FileCheck %s
+! RUN: %flang -### -S %s -o - 2>&1 | FileCheck %s --check-prefixes=NO-INIT
! Check that the compiler accepts -finit-local-zero:
-! RUN: %flang_fc1 -emit-hlfir -finit-local-zero %s -o /dev/null
+! RUN: %flang_fc1 -finit-local-zero %s -o /dev/null
! CHECK: "-fc1"{{.*}}"-finit-local-zero"
+! NO-INIT-NOT: -finit-local-zero
diff --git a/flang/test/Lower/init-local-zero.f90 b/flang/test/Lower/init-local-zero.f90
index 61a4d70ad788d..2ed8ca2f615dd 100644
--- a/flang/test/Lower/init-local-zero.f90
+++ b/flang/test/Lower/init-local-zero.f90
@@ -1,66 +1,69 @@
! RUN: %flang_fc1 -emit-hlfir -finit-local-zero -o - %s | FileCheck %s
-
!CHECK-LABEL: func.func @_QPuninitialized_integer() {
-!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca i32
!CHECK: %[[X_ALLOCA:.*]] = fir.alloca i32 {bindc_name = "x", uniq_name = "_QFuninitialized_integerEx"}
!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_integerEx"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
!CHECK: %[[ZERO:.*]] = arith.constant 0 : i32
-!CHECK: fir.store %[[ZERO]] to %[[ZERO_ALLOCA]] : !fir.ref<i32>
-!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<i32>, !fir.ref<i32>
+!CHECK: hlfir.assign %[[ZERO]] to %[[X]]#0 : i32, !fir.ref<i32>
subroutine uninitialized_integer
integer :: x
end subroutine
!CHECK-LABEL: func.func @_QPuninitialized_real() {
-!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca f32
!CHECK: %[[X_ALLOCA:.*]] = fir.alloca f32 {bindc_name = "x", uniq_name = "_QFuninitialized_realEx"}
!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_realEx"} : (!fir.ref<f32>) -> (!fir.ref<f32>, !fir.ref<f32>)
!CHECK: %[[ZERO:.*]] = arith.constant 0.000000e+00 : f32
-!CHECK: fir.store %[[ZERO]] to %[[ZERO_ALLOCA]] : !fir.ref<f32>
-!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<f32>, !fir.ref<f32>
+!CHECK: hlfir.assign %[[ZERO]] to %[[X]]#0 : f32, !fir.ref<f32>
subroutine uninitialized_real
real :: x
end subroutine
!CHECK-LABEL: func.func @_QPuninitialized_logical() {
-!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca !fir.logical<4>
!CHECK: %[[X_ALLOCA:.*]] = fir.alloca !fir.logical<4> {bindc_name = "x", uniq_name = "_QFuninitialized_logicalEx"}
!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_logicalEx"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
!CHECK: %false = arith.constant false
!CHECK: %[[CVT:.*]] = fir.convert %false : (i1) -> !fir.logical<4>
-!CHECK: fir.store %[[CVT]] to %[[ZERO_ALLOCA]] : !fir.ref<!fir.logical<4>>
-!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>
+!CHECK: hlfir.assign %[[CVT]] to %[[X]]#0 : !fir.logical<4>, !fir.ref<!fir.logical<4>>
subroutine uninitialized_logical
logical :: x
end subroutine
!CHECK-LABEL: func.func @_QPuninitialized_complex() {
-!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca complex<f32>
!CHECK: %[[X_ALLOCA:.*]] = fir.alloca complex<f32> {bindc_name = "x", uniq_name = "_QFuninitialized_complexEx"}
!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {uniq_name = "_QFuninitialized_complexEx"} : (!fir.ref<complex<f32>>) -> (!fir.ref<complex<f32>>, !fir.ref<complex<f32>>)
!CHECK: %[[CONST:.*]] = arith.constant 0.000000e+00 : f32
!CHECK: %[[UNDEF:.*]] = fir.undefined complex<f32>
!CHECK: %[[IDX0:.*]] = fir.insert_value %[[UNDEF]], %[[CONST]], [0 : index] : (complex<f32>, f32) -> complex<f32>
!CHECK: %[[IDX1:.*]] = fir.insert_value %[[IDX0]], %[[CONST]], [1 : index] : (complex<f32>, f32) -> complex<f32>
-!CHECK: fir.store %[[IDX1]] to %[[ZERO_ALLOCA]] : !fir.ref<complex<f32>>
-!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<complex<f32>>, !fir.ref<complex<f32>>
+!CHECK: hlfir.assign %[[IDX1]] to %[[X]]#0 : complex<f32>, !fir.ref<complex<f32>>
subroutine uninitialized_complex
complex :: x
end subroutine
!CHECK-LABEL: func.func @_QPuninitialized_character() {
-!CHECK: %[[ZERO_ALLOCA:.*]] = fir.alloca !fir.char<1>
!CHECK: %[[ONE:.*]] = arith.constant 1 : index
!CHECK: %[[X_ALLOCA:.*]] = fir.alloca !fir.char<1> {bindc_name = "x", uniq_name = "_QFuninitialized_characterEx"}
-!CHECK: %3:2 = hlfir.declare %[[X_ALLOCA]] typeparams %[[ONE]] {uniq_name = "_QFuninitialized_characterEx"} : (!fir.ref<!fir.char<1>>, index) -> (!fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>)
-!CHECK: %[[CONST:.*]] = arith.constant 0 : i32
-!CHECK: %[[CVT:.*]] = fir.convert %[[CONST]] : (i32) -> i8
-!CHECK: %[[UNDEF:.*]] = fir.undefined !fir.char<1>
-!CHECK: %[[VAL:.*]] = fir.insert_value %[[UNDEF]], %[[CVT]], [0 : index] : (!fir.char<1>, i8) -> !fir.char<1>
-!CHECK: fir.store %[[VAL]] to %[[ZERO_ALLOCA]] : !fir.ref<!fir.char<1>>
-!CHECK: hlfir.assign %[[ZERO_ALLOCA]] to %[[X]]#0 : !fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] typeparams %[[ONE]] {uniq_name = "_QFuninitialized_characterEx"} : (!fir.ref<!fir.char<1>>, index) -> (!fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>)
+!CHECK: %[[CVT:.*]] = fir.convert %[[ONE]] : (index) -> i64
+!CHECK: %[[CONST:.*]] = arith.constant 1 : i64
+!CHECK: %[[COUNT:.*]] = arith.muli %[[CVT]], %[[CONST]] : i64
+!CHECK: %[[CVT:.*]] = fir.convert %[[X]]#0 : (!fir.ref<!fir.char<1>>) -> !llvm.ptr
+!CHECK: %[[ZERO:.*]] = arith.constant 0 : i8
+!CHECK: "llvm.intr.memset"(%[[CVT]], %[[ZERO]], %[[COUNT]]) <{isVolatile = false}> : (!llvm.ptr, i8, i64) -> ()
subroutine uninitialized_character
character :: x
end subroutine
+
+!CHECK: %[[X_ALLOCA:.*]] = fir.alloca !fir.box<!fir.heap<i32>> {bindc_name = "x", uniq_name = "_QFallocatable_scalarEx"}
+!CHECK: %[[ZERO_BITS:.*]] = fir.zero_bits !fir.heap<i32>
+!CHECK: %[[EMBOX:.*]] = fir.embox %[[ZERO_BITS]] : (!fir.heap<i32>) -> !fir.box<!fir.heap<i32>>
+!CHECK: fir.store %[[EMBOX]] to %[[X_ALLOCA]] : !fir.ref<!fir.box<!fir.heap<i32>>>
+!CHECK: %[[X:.*]]:2 = hlfir.declare %[[X_ALLOCA]] {fortran_attrs = #fir.var_attrs<allocatable>, uniq_name = "_QFallocatable_scalarEx"} : (!fir.ref<!fir.box<!fir.heap<i32>>>) -> (!fir.ref<!fir.box<!fir.heap<i32>>>, !fir.ref<!fir.box<!fir.heap<i32>>>)
+!CHECK: %[[ZERO:.*]] = arith.constant 0 : i32
+!CHECK: %[[LOAD:.*]] = fir.load %[[X]]#0 : !fir.ref<!fir.box<!fir.heap<i32>>>
+!CHECK: %[[ADDR:.*]] = fir.box_addr %[[LOAD]] : (!fir.box<!fir.heap<i32>>) -> !fir.heap<i32>
+!CHECK: hlfir.assign %[[ZERO]] to %[[ADDR]] : i32, !fir.heap<i32>
+subroutine allocatable_scalar
+ integer, allocatable :: x
+end subroutine
>From 0227f5e2f61e0688b81221354a29fcfbd0dc3822 Mon Sep 17 00:00:00 2001
From: NimishMishra <neelam.nimish at gmail.com>
Date: Sun, 26 Jul 2026 18:35:00 +0530
Subject: [PATCH 6/6] Do not run the entire pipeline for the test
---
flang/test/Driver/finit-local-zero.f90 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/flang/test/Driver/finit-local-zero.f90 b/flang/test/Driver/finit-local-zero.f90
index b69fe60ba1e70..2de41e4df34f8 100644
--- a/flang/test/Driver/finit-local-zero.f90
+++ b/flang/test/Driver/finit-local-zero.f90
@@ -3,7 +3,7 @@
! RUN: %flang -### -S %s -o - 2>&1 | FileCheck %s --check-prefixes=NO-INIT
! Check that the compiler accepts -finit-local-zero:
-! RUN: %flang_fc1 -finit-local-zero %s -o /dev/null
+! RUN: %flang_fc1 -fsyntax-only -finit-local-zero %s -o /dev/null
! CHECK: "-fc1"{{.*}}"-finit-local-zero"
! NO-INIT-NOT: -finit-local-zero
More information about the cfe-commits
mailing list