[flang-commits] [flang] [Flang] Add FIR and LLVM lowering support for prefetch directive (PR #167272)
Thirumalai Shaktivel via flang-commits
flang-commits at lists.llvm.org
Mon Dec 8 22:14:41 PST 2025
https://github.com/Thirumalai-Shaktivel updated https://github.com/llvm/llvm-project/pull/167272
>From 79adc2b620b6cbecff043a581412eeab3ca4a255 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Mon, 10 Nov 2025 06:11:37 +0000
Subject: [PATCH 1/9] [Flang] Add FIR and LLVM lowering support for prefetch
directive
* Add PrefetchOp in FirOps
* Handle PrefetchOp in FIR Lowering and also pass required
default values
* Handle PrefetchOp in CodeGen.cpp
* Add required tests
---
.../include/flang/Optimizer/Dialect/FIROps.td | 30 +++++++++
flang/lib/Lower/Bridge.cpp | 19 +++++-
flang/lib/Optimizer/CodeGen/CodeGen.cpp | 36 ++++++++---
flang/test/Integration/prefetch.f90 | 39 ++++++++++++
flang/test/Lower/HLFIR/prefetch.f90 | 63 +++++++++++++++++++
5 files changed, 178 insertions(+), 9 deletions(-)
create mode 100644 flang/test/Integration/prefetch.f90
create mode 100644 flang/test/Lower/HLFIR/prefetch.f90
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index bae52d63fda45..84d7ed29292ae 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -351,6 +351,36 @@ def fir_StoreOp : fir_Op<"store", [FirAliasTagOpInterface,
}];
}
+def fir_PrefetchOp : fir_Op<"prefetch", []> {
+ let summary = "prefetch a memory reference";
+
+ let description = [{
+ The prefetch is a hint to the code generator that the memory reference will
+ be used in the near future. The prefetch is not guaranteed to be executed.
+
+ ```
+ %a = ... -> !fir.ref<i32>
+ fir.prefetch %a {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ // ...
+ fir.load %a : !fir.ref<i32> // use the prefetched value
+ ```
+ }];
+
+ /// `memref' is the address to be prefetched
+ /// `rw' : rw specifier >
+ /// read is 0, write is 1
+ /// `localityHint': temporal locality specifier >
+ /// value ranging from 0 - no locality to 3 - extremely local
+ /// `cacheType' : cache type specifier >
+ /// instruction cache is 0, data cache is 1
+ let arguments = (ins AnyReferenceLike:$memref,
+ ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<1>]>:$rw,
+ ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<3>]>:$localityHint,
+ ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<1>]>:$cacheType);
+
+ let assemblyFormat = "$memref attr-dict `:` type(operands)";
+}
+
def fir_CopyOp : fir_Op<"copy", [DeclareOpInterfaceMethods<MemoryEffectsOpInterface>]> {
let summary = "copy constant size memory";
diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 5779bcd5d293c..9d8e765e8adea 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -3276,7 +3276,24 @@ class FirConverter : public Fortran::lower::AbstractConverter {
attachInliningDirectiveToStmt(dir, &eval);
},
[&](const Fortran::parser::CompilerDirective::Prefetch &prefetch) {
- TODO(getCurrentLocation(), "!$dir prefetch");
+ for (const auto &p : prefetch.v) {
+ Fortran::evaluate::ExpressionAnalyzer ea{
+ bridge.getSemanticsContext()};
+ Fortran::lower::SomeExpr expr{*ea.Analyze(
+ std::get<Fortran::parser::DataRef>(p.value().u))};
+ Fortran::lower::StatementContext stmtCtx;
+ mlir::Value memRef{Fortran::lower::convertExprToHLFIR(
+ genLocation(dir.source), *this, expr,
+ localSymbols, stmtCtx)
+ .getBase()};
+
+ // TODO: Don't use default value, instead get the following
+ // info from the directive
+ uint32_t isWrite{0}, localityHint{3}, isData{1};
+ builder->create<fir::PrefetchOp>(genLocation(dir.source),
+ memRef, isWrite, localityHint,
+ isData);
+ }
},
[&](const auto &) {}},
dir.u);
diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index ca4aefb653d2a..69734a2ae443d 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -3346,6 +3346,25 @@ struct GlobalOpConversion : public fir::FIROpConversion<fir::GlobalOp> {
}
};
+/// `fir.prefetch` --> `llvm.prefetch`
+struct PrefetchOpConversion : public fir::FIROpConversion<fir::PrefetchOp> {
+ using FIROpConversion::FIROpConversion;
+
+ llvm::LogicalResult
+ matchAndRewrite(fir::PrefetchOp prefetch, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const override {
+ llvm::errs() << "prefetch\n";
+ mlir::IntegerAttr rw = prefetch.getRwAttr();
+ mlir::IntegerAttr localityHint = prefetch.getLocalityHintAttr();
+ mlir::IntegerAttr cacheType = prefetch.getCacheTypeAttr();
+ mlir::LLVM::Prefetch::create(rewriter, prefetch.getLoc(),
+ adaptor.getOperands().front(), rw,
+ localityHint, cacheType);
+ rewriter.eraseOp(prefetch);
+ return mlir::success();
+ }
+};
+
/// `fir.load` --> `llvm.load`
struct LoadOpConversion : public fir::FIROpConversion<fir::LoadOp> {
using FIROpConversion::FIROpConversion;
@@ -4423,14 +4442,15 @@ void fir::populateFIRToLLVMConversionPatterns(
FirEndOpConversion, FreeMemOpConversion, GlobalLenOpConversion,
GlobalOpConversion, InsertOnRangeOpConversion, IsPresentOpConversion,
LenParamIndexOpConversion, LoadOpConversion, MulcOpConversion,
- NegcOpConversion, NoReassocOpConversion, SelectCaseOpConversion,
- SelectOpConversion, SelectRankOpConversion, SelectTypeOpConversion,
- ShapeOpConversion, ShapeShiftOpConversion, ShiftOpConversion,
- SliceOpConversion, StoreOpConversion, StringLitOpConversion,
- SubcOpConversion, TypeDescOpConversion, TypeInfoOpConversion,
- UnboxCharOpConversion, UnboxProcOpConversion, UndefOpConversion,
- UnreachableOpConversion, XArrayCoorOpConversion, XEmboxOpConversion,
- XReboxOpConversion, ZeroOpConversion>(converter, options);
+ NegcOpConversion, NoReassocOpConversion, PrefetchOpConversion,
+ SelectCaseOpConversion, SelectOpConversion, SelectRankOpConversion,
+ SelectTypeOpConversion, ShapeOpConversion, ShapeShiftOpConversion,
+ ShiftOpConversion, SliceOpConversion, StoreOpConversion,
+ StringLitOpConversion, SubcOpConversion, TypeDescOpConversion,
+ TypeInfoOpConversion, UnboxCharOpConversion, UnboxProcOpConversion,
+ UndefOpConversion, UnreachableOpConversion, XArrayCoorOpConversion,
+ XEmboxOpConversion, XReboxOpConversion, ZeroOpConversion>(converter,
+ options);
// Patterns that are populated without a type converter do not trigger
// target materializations for the operands of the root op.
diff --git a/flang/test/Integration/prefetch.f90 b/flang/test/Integration/prefetch.f90
new file mode 100644
index 0000000000000..1f7f6d091cfaa
--- /dev/null
+++ b/flang/test/Integration/prefetch.f90
@@ -0,0 +1,39 @@
+!===----------------------------------------------------------------------===!
+! This directory can be used to add Integration tests involving multiple
+! stages of the compiler (for eg. from Fortran to LLVM IR). It should not
+! contain executable tests. We should only add tests here sparingly and only
+! if there is no other way to test. Repeat this message in each test that is
+! added to this directory and sub-directories.
+!===----------------------------------------------------------------------===!
+
+! RUN: %flang_fc1 -emit-llvm -o - %s | FileCheck %s --check-prefixes=LLVM
+
+!===============================================================================
+! Test lowering of prefetch directive
+!===============================================================================
+
+subroutine test_prefetch_01()
+ ! LLVM: {{.*}} = alloca i32, i64 1, align 4
+ ! LLVM: %[[L_J:.*]] = alloca i32, i64 1, align 4
+ ! LLVM: %[[L_I:.*]] = alloca i32, i64 1, align 4
+ ! LLVM: %[[L_A:.*]] = alloca [256 x i32], i64 1, align 4
+
+ integer :: i, j
+ integer :: a(256)
+
+ a = 23
+ ! LLVM: call void @llvm.prefetch.p0(ptr %6, i32 0, i32 3, i32 1)
+ !dir$ prefetch a
+ i = sum(a)
+ ! LLVM: %[[L_LOAD:.*]] = load i32, ptr %5, align 4
+ ! LLVM: %[[L_ADD:.*]] = add nsw i32 %[[L_LOAD]], 64
+ ! LLVM: %[[L_GEP:.*]] = getelementptr i32, ptr %[[L_A]], i64 {{.*}}
+
+ ! LLVM: call void @llvm.prefetch.p0(ptr %[[L_GEP]], i32 0, i32 3, i32 1)
+ ! LLVM: call void @llvm.prefetch.p0(ptr %[[L_J]], i32 0, i32 3, i32 1)
+
+ do i = 1, (256 - 64)
+ !dir$ prefetch a(i+64), j
+ a(i) = a(i-32) + a(i+32) + j
+ end do
+end subroutine test_prefetch_01
diff --git a/flang/test/Lower/HLFIR/prefetch.f90 b/flang/test/Lower/HLFIR/prefetch.f90
new file mode 100644
index 0000000000000..3fe0a1a18c4c3
--- /dev/null
+++ b/flang/test/Lower/HLFIR/prefetch.f90
@@ -0,0 +1,63 @@
+! Test lowering of prefetch directive
+! RUN: %flang_fc1 -emit-hlfir -o - %s | FileCheck %s --check-prefixes=HLFIR
+
+module test_prefetch_mod
+ implicit none
+ type :: t
+ integer :: a(256, 256)
+ end type t
+end module test_prefetch_mod
+
+subroutine test_prefetch_01()
+ ! HLFIR: %[[H_A:.*]]:2 = hlfir.declare {{.*}} {uniq_name = "_QFtest_prefetch_01Ea"} : (!fir.ref<!fir.array<256xi32>>, !fir.shape<1>) -> (!fir.ref<!fir.array<256xi32>>, !fir.ref<!fir.array<256xi32>>)
+ ! HLFIR: %[[H_I:.*]]:2 = hlfir.declare {{.*}} {uniq_name = "_QFtest_prefetch_01Ei"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+ ! HLFIR: %[[H_J:.*]]:2 = hlfir.declare {{.*}} {uniq_name = "_QFtest_prefetch_01Ej"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+
+ integer :: i, j
+ integer :: a(256)
+
+ a = 23
+
+ ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.array<256xi32>>
+ !dir$ prefetch a
+ i = sum(a)
+
+ ! HLFIR: %[[H_LOAD:.*]] = fir.load %[[H_I]]#0 : !fir.ref<i32>
+ ! HLFIR: %[[H_C64:.*]] = arith.constant 64 : i32
+ ! HLFIR: %[[H_ADD:.*]] = arith.addi %[[H_LOAD]], %[[H_C64]] overflow<nsw> : i32
+ ! HLFIR: %[[H_CON:.*]] = fir.convert %[[H_ADD]] : (i32) -> i64
+ ! HLFIR: %[[H_DESIG:.*]] = hlfir.designate %[[H_A]]#0 (%[[H_CON]]) : (!fir.ref<!fir.array<256xi32>>, i64) -> !fir.ref<i32>
+
+ ! HLFIR: fir.prefetch %[[H_DESIG]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ ! HLFIR: fir.prefetch %[[H_J]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+
+ do i = 1, (256 - 64)
+ !dir$ prefetch a(i+64), j
+ a(i) = a(i-32) + a(i+32) + j
+ end do
+end subroutine test_prefetch_01
+
+subroutine test_prefetch_02(t1)
+ use test_prefetch_mod
+ ! HLFIR: %[[H_A:.*]]:2 = hlfir.declare {{.*}} {fortran_attrs = #fir.var_attrs<allocatable>, uniq_name = "_QFtest_prefetch_02Ea"}
+ ! HLFIR: %[[H_ARG0:.*]]:2 = hlfir.declare {{.*}} dummy_scope {{.*}} {fortran_attrs = #fir.var_attrs<intent_inout>, uniq_name = "_QFtest_prefetch_02Et1"}
+ type(t), intent(inout) :: t1
+ integer, allocatable :: a(:, :)
+
+ ! HLFIR: %[[H_DESIG_01:.*]] = hlfir.designate %[[H_ARG0]]#0{"a"} shape {{.*}}
+ ! HLFIR: fir.prefetch %[[H_DESIG_01]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.array<256x256xi32>>
+ !dir$ prefetch t1%a
+ a = t1%a ** 2
+
+ do i = 1, 256
+ ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.box<!fir.heap<!fir.array<?x?xi32>>>>
+ !dir$ prefetch a
+ a(i, :) = a(i, :) + i
+ do j = 1, 256
+ ! HLFIR: %[[H_DESIG_02:.*]] = hlfir.designate %[[H_ARG0]]#0{"a"} {{.*}}
+ ! HLFIR: fir.prefetch %[[H_DESIG_02]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ !dir$ prefetch t1%a(i, j)
+ t1%a(i, j) = (a(i, j) + i*j) / t1%a(i, j)
+ end do
+ end do
+end subroutine test_prefetch_02
>From 32738eb0c716e7d8e19a28f28c861577af804c14 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Mon, 10 Nov 2025 15:49:33 +0000
Subject: [PATCH 2/9] Fix the build failure
---
flang/lib/Lower/Bridge.cpp | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 9d8e765e8adea..ce6b9f58bbfd7 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -3290,9 +3290,8 @@ class FirConverter : public Fortran::lower::AbstractConverter {
// TODO: Don't use default value, instead get the following
// info from the directive
uint32_t isWrite{0}, localityHint{3}, isData{1};
- builder->create<fir::PrefetchOp>(genLocation(dir.source),
- memRef, isWrite, localityHint,
- isData);
+ fir::PrefetchOp::create(*builder, genLocation(dir.source),
+ memRef, isWrite, localityHint, isData);
}
},
[&](const auto &) {}},
>From 9557cd0f4b118d9b95e932a0d7c61b238c49d4d0 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Tue, 11 Nov 2025 03:08:15 +0000
Subject: [PATCH 3/9] Remove debug print
---
flang/lib/Optimizer/CodeGen/CodeGen.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index 69734a2ae443d..adc5a50c45fff 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -3353,7 +3353,6 @@ struct PrefetchOpConversion : public fir::FIROpConversion<fir::PrefetchOp> {
llvm::LogicalResult
matchAndRewrite(fir::PrefetchOp prefetch, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const override {
- llvm::errs() << "prefetch\n";
mlir::IntegerAttr rw = prefetch.getRwAttr();
mlir::IntegerAttr localityHint = prefetch.getLocalityHintAttr();
mlir::IntegerAttr cacheType = prefetch.getCacheTypeAttr();
>From c28bbc29f184f024ea31e113be9a718c252d64c7 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Tue, 11 Nov 2025 08:38:05 +0000
Subject: [PATCH 4/9] Use UnitAttr instead of I32Attr
---
flang/include/flang/Optimizer/Dialect/FIROps.td | 12 ++++++------
flang/lib/Optimizer/CodeGen/CodeGen.cpp | 6 ++++--
flang/test/Lower/HLFIR/prefetch.f90 | 12 ++++++------
3 files changed, 16 insertions(+), 14 deletions(-)
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index 84d7ed29292ae..4f7abb1d052b7 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -368,15 +368,15 @@ def fir_PrefetchOp : fir_Op<"prefetch", []> {
/// `memref' is the address to be prefetched
/// `rw' : rw specifier >
- /// read is 0, write is 1
+ /// read is 0 (default), write is 1
/// `localityHint': temporal locality specifier >
/// value ranging from 0 - no locality to 3 - extremely local
/// `cacheType' : cache type specifier >
- /// instruction cache is 0, data cache is 1
- let arguments = (ins AnyReferenceLike:$memref,
- ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<1>]>:$rw,
+ /// instruction cache is 0 (default), data cache is 1
+ /// NOTE: The numerical values used here is in reference to the LLVM LangRef
+ let arguments = (ins AnyReferenceLike:$memref, UnitAttr:$rw,
ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<3>]>:$localityHint,
- ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<1>]>:$cacheType);
+ UnitAttr:$cacheType);
let assemblyFormat = "$memref attr-dict `:` type(operands)";
}
@@ -974,7 +974,7 @@ def fir_ReboxAssumedRankOp : fir_Op<"rebox_assumed_rank",
Example:
```
fir.rebox_assumed_rank %1 lbs zeroes : (!fir.box<!fir.array<*:f32>>) -> !fir.box<!fir.array<*:f32>>
- ```
+ ```
}];
let arguments = (ins
diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index adc5a50c45fff..8a1fe5fc5d988 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -3353,9 +3353,11 @@ struct PrefetchOpConversion : public fir::FIROpConversion<fir::PrefetchOp> {
llvm::LogicalResult
matchAndRewrite(fir::PrefetchOp prefetch, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const override {
- mlir::IntegerAttr rw = prefetch.getRwAttr();
+ mlir::IntegerAttr rw = mlir::IntegerAttr::get(rewriter.getI32Type(),
+ prefetch.getRwAttr() ? 1 : 0);
mlir::IntegerAttr localityHint = prefetch.getLocalityHintAttr();
- mlir::IntegerAttr cacheType = prefetch.getCacheTypeAttr();
+ mlir::IntegerAttr cacheType = mlir::IntegerAttr::get(
+ rewriter.getI32Type(), prefetch.getCacheTypeAttr() ? 1 : 0);
mlir::LLVM::Prefetch::create(rewriter, prefetch.getLoc(),
adaptor.getOperands().front(), rw,
localityHint, cacheType);
diff --git a/flang/test/Lower/HLFIR/prefetch.f90 b/flang/test/Lower/HLFIR/prefetch.f90
index 3fe0a1a18c4c3..2f33a78b0b396 100644
--- a/flang/test/Lower/HLFIR/prefetch.f90
+++ b/flang/test/Lower/HLFIR/prefetch.f90
@@ -18,7 +18,7 @@ subroutine test_prefetch_01()
a = 23
- ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.array<256xi32>>
+ ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType, localityHint = 3 : i32} : !fir.ref<!fir.array<256xi32>>
!dir$ prefetch a
i = sum(a)
@@ -28,8 +28,8 @@ subroutine test_prefetch_01()
! HLFIR: %[[H_CON:.*]] = fir.convert %[[H_ADD]] : (i32) -> i64
! HLFIR: %[[H_DESIG:.*]] = hlfir.designate %[[H_A]]#0 (%[[H_CON]]) : (!fir.ref<!fir.array<256xi32>>, i64) -> !fir.ref<i32>
- ! HLFIR: fir.prefetch %[[H_DESIG]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
- ! HLFIR: fir.prefetch %[[H_J]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ ! HLFIR: fir.prefetch %[[H_DESIG]] {cacheType, localityHint = 3 : i32} : !fir.ref<i32>
+ ! HLFIR: fir.prefetch %[[H_J]]#0 {cacheType, localityHint = 3 : i32} : !fir.ref<i32>
do i = 1, (256 - 64)
!dir$ prefetch a(i+64), j
@@ -45,17 +45,17 @@ subroutine test_prefetch_02(t1)
integer, allocatable :: a(:, :)
! HLFIR: %[[H_DESIG_01:.*]] = hlfir.designate %[[H_ARG0]]#0{"a"} shape {{.*}}
- ! HLFIR: fir.prefetch %[[H_DESIG_01]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.array<256x256xi32>>
+ ! HLFIR: fir.prefetch %[[H_DESIG_01]] {cacheType, localityHint = 3 : i32} : !fir.ref<!fir.array<256x256xi32>>
!dir$ prefetch t1%a
a = t1%a ** 2
do i = 1, 256
- ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<!fir.box<!fir.heap<!fir.array<?x?xi32>>>>
+ ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType, localityHint = 3 : i32} : !fir.ref<!fir.box<!fir.heap<!fir.array<?x?xi32>>>>
!dir$ prefetch a
a(i, :) = a(i, :) + i
do j = 1, 256
! HLFIR: %[[H_DESIG_02:.*]] = hlfir.designate %[[H_ARG0]]#0{"a"} {{.*}}
- ! HLFIR: fir.prefetch %[[H_DESIG_02]] {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ ! HLFIR: fir.prefetch %[[H_DESIG_02]] {cacheType, localityHint = 3 : i32} : !fir.ref<i32>
!dir$ prefetch t1%a(i, j)
t1%a(i, j) = (a(i, j) + i*j) / t1%a(i, j)
end do
>From 7c921f805899c8d46cec3c5a268373bf0174e01c Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Tue, 11 Nov 2025 08:38:30 +0000
Subject: [PATCH 5/9] Fix the tests
---
flang/test/Integration/prefetch.f90 | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/flang/test/Integration/prefetch.f90 b/flang/test/Integration/prefetch.f90
index 1f7f6d091cfaa..f3fb7a950e328 100644
--- a/flang/test/Integration/prefetch.f90
+++ b/flang/test/Integration/prefetch.f90
@@ -14,24 +14,24 @@
subroutine test_prefetch_01()
! LLVM: {{.*}} = alloca i32, i64 1, align 4
- ! LLVM: %[[L_J:.*]] = alloca i32, i64 1, align 4
- ! LLVM: %[[L_I:.*]] = alloca i32, i64 1, align 4
- ! LLVM: %[[L_A:.*]] = alloca [256 x i32], i64 1, align 4
+ ! LLVM: %[[VAR_J:.*]] = alloca i32, i64 1, align 4
+ ! LLVM: %[[VAR_I:.*]] = alloca i32, i64 1, align 4
+ ! LLVM: %[[VAR_A:.*]] = alloca [256 x i32], i64 1, align 4
integer :: i, j
integer :: a(256)
a = 23
- ! LLVM: call void @llvm.prefetch.p0(ptr %6, i32 0, i32 3, i32 1)
+ ! LLVM: call void @llvm.prefetch.p0(ptr %[[VAR_A]], i32 0, i32 3, i32 1)
!dir$ prefetch a
i = sum(a)
- ! LLVM: %[[L_LOAD:.*]] = load i32, ptr %5, align 4
- ! LLVM: %[[L_ADD:.*]] = add nsw i32 %[[L_LOAD]], 64
- ! LLVM: %[[L_GEP:.*]] = getelementptr i32, ptr %[[L_A]], i64 {{.*}}
- ! LLVM: call void @llvm.prefetch.p0(ptr %[[L_GEP]], i32 0, i32 3, i32 1)
- ! LLVM: call void @llvm.prefetch.p0(ptr %[[L_J]], i32 0, i32 3, i32 1)
+ ! LLVM: %[[LOAD_I:.*]] = load i32, ptr %[[VAR_I]], align 4
+ ! LLVM: %{{.*}} = add nsw i32 %[[LOAD_I]], 64
+ ! LLVM: %[[GEP_A:.*]] = getelementptr i32, ptr %[[VAR_A]], i64 {{.*}}
+ ! LLVM: call void @llvm.prefetch.p0(ptr %[[GEP_A]], i32 0, i32 3, i32 1)
+ ! LLVM: call void @llvm.prefetch.p0(ptr %[[VAR_J]], i32 0, i32 3, i32 1)
do i = 1, (256 - 64)
!dir$ prefetch a(i+64), j
a(i) = a(i-32) + a(i+32) + j
>From 7c98c645fe7c4978a4d4ede15f65c3b04a25fbe5 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Thu, 13 Nov 2025 06:12:20 +0000
Subject: [PATCH 6/9] Revert a space fix
---
flang/include/flang/Optimizer/Dialect/FIROps.td | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index 4f7abb1d052b7..4b6eb98bc3530 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -974,7 +974,7 @@ def fir_ReboxAssumedRankOp : fir_Op<"rebox_assumed_rank",
Example:
```
fir.rebox_assumed_rank %1 lbs zeroes : (!fir.box<!fir.array<*:f32>>) -> !fir.box<!fir.array<*:f32>>
- ```
+ ```
}];
let arguments = (ins
>From 1da8a9517cec8ba2babad0750408a8f811c951b2 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Thu, 13 Nov 2025 15:52:08 +0000
Subject: [PATCH 7/9] Use Data instead of Box for allocatable array
---
flang/lib/Lower/Bridge.cpp | 13 +++++++++----
flang/test/Lower/HLFIR/prefetch.f90 | 4 +++-
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index ce6b9f58bbfd7..d6062bbabf821 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -3282,16 +3282,21 @@ class FirConverter : public Fortran::lower::AbstractConverter {
Fortran::lower::SomeExpr expr{*ea.Analyze(
std::get<Fortran::parser::DataRef>(p.value().u))};
Fortran::lower::StatementContext stmtCtx;
+ mlir::Location loc = genLocation(dir.source);
mlir::Value memRef{Fortran::lower::convertExprToHLFIR(
- genLocation(dir.source), *this, expr,
- localSymbols, stmtCtx)
+ loc, *this, expr, localSymbols, stmtCtx)
.getBase()};
+ if (mlir::isa<fir::BaseBoxType>(
+ fir::unwrapRefType(memRef.getType()))) {
+ memRef = fir::LoadOp::create(*builder, loc, memRef);
+ memRef = fir::BoxAddrOp::create(*builder, loc, memRef);
+ }
// TODO: Don't use default value, instead get the following
// info from the directive
uint32_t isWrite{0}, localityHint{3}, isData{1};
- fir::PrefetchOp::create(*builder, genLocation(dir.source),
- memRef, isWrite, localityHint, isData);
+ fir::PrefetchOp::create(*builder, loc, memRef, isWrite,
+ localityHint, isData);
}
},
[&](const auto &) {}},
diff --git a/flang/test/Lower/HLFIR/prefetch.f90 b/flang/test/Lower/HLFIR/prefetch.f90
index 2f33a78b0b396..2a30584d94563 100644
--- a/flang/test/Lower/HLFIR/prefetch.f90
+++ b/flang/test/Lower/HLFIR/prefetch.f90
@@ -50,7 +50,9 @@ subroutine test_prefetch_02(t1)
a = t1%a ** 2
do i = 1, 256
- ! HLFIR: fir.prefetch %[[H_A]]#0 {cacheType, localityHint = 3 : i32} : !fir.ref<!fir.box<!fir.heap<!fir.array<?x?xi32>>>>
+ ! HLFIR: %[[A_LOAD:.*]] = fir.load %[[H_A]]#0 : !fir.ref<!fir.box<!fir.heap<!fir.array<?x?xi32>>>>
+ ! HLFIR: %[[A_BOX:.*]] = fir.box_addr %[[A_LOAD]] : (!fir.box<!fir.heap<!fir.array<?x?xi32>>>) -> !fir.heap<!fir.array<?x?xi32>>
+ ! HLFIR: fir.prefetch %[[A_BOX]] {cacheType, localityHint = 3 : i32} : !fir.heap<!fir.array<?x?xi32>>
!dir$ prefetch a
a(i, :) = a(i, :) + i
do j = 1, 256
>From ed117745c512deea862dd923287a130310f52bb7 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Wed, 26 Nov 2025 12:15:04 +0530
Subject: [PATCH 8/9] Fix the FIROps prefetch description
---
flang/include/flang/Optimizer/Dialect/FIROps.td | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index 4b6eb98bc3530..78376a3ce17bc 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -360,7 +360,7 @@ def fir_PrefetchOp : fir_Op<"prefetch", []> {
```
%a = ... -> !fir.ref<i32>
- fir.prefetch %a {cacheType = 1 : i32, localityHint = 3 : i32, rw = 0 : i32} : !fir.ref<i32>
+ fir.prefetch %a {cacheType, localityHint = 3 : i32} : !fir.ref<i32>
// ...
fir.load %a : !fir.ref<i32> // use the prefetched value
```
@@ -372,11 +372,14 @@ def fir_PrefetchOp : fir_Op<"prefetch", []> {
/// `localityHint': temporal locality specifier >
/// value ranging from 0 - no locality to 3 - extremely local
/// `cacheType' : cache type specifier >
- /// instruction cache is 0 (default), data cache is 1
+ /// instruction cache is 0, data cache is 1 (default)
/// NOTE: The numerical values used here is in reference to the LLVM LangRef
- let arguments = (ins AnyReferenceLike:$memref, UnitAttr:$rw,
- ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<3>]>:$localityHint,
- UnitAttr:$cacheType);
+ let arguments =
+ (ins Arg<AnyReferenceLike,
+ "prefetch memory address", [MemWrite]> : $memref,
+ UnitAttr : $rw,
+ ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<3>]> : $localityHint,
+ UnitAttr : $cacheType);
let assemblyFormat = "$memref attr-dict `:` type(operands)";
}
@@ -974,7 +977,7 @@ def fir_ReboxAssumedRankOp : fir_Op<"rebox_assumed_rank",
Example:
```
fir.rebox_assumed_rank %1 lbs zeroes : (!fir.box<!fir.array<*:f32>>) -> !fir.box<!fir.array<*:f32>>
- ```
+ ```
}];
let arguments = (ins
>From e7ab97474bf1514a9f3b8455e1555917cbc8dd25 Mon Sep 17 00:00:00 2001
From: Thirumalai-Shaktivel <thirumalaishaktivel at gmail.com>
Date: Tue, 9 Dec 2025 09:47:32 +0530
Subject: [PATCH 9/9] Improve the arguments repesentation in FIR
---
.../include/flang/Optimizer/Dialect/FIROps.td | 4 +-
flang/lib/Optimizer/Dialect/FIROps.cpp | 81 +++++++++++++++++++
2 files changed, 83 insertions(+), 2 deletions(-)
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index 78376a3ce17bc..55ce0be027e59 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -360,7 +360,7 @@ def fir_PrefetchOp : fir_Op<"prefetch", []> {
```
%a = ... -> !fir.ref<i32>
- fir.prefetch %a {cacheType, localityHint = 3 : i32} : !fir.ref<i32>
+ fir.prefetch %a {read, data, localityHint = 3 : i32} : !fir.ref<i32>
// ...
fir.load %a : !fir.ref<i32> // use the prefetched value
```
@@ -381,7 +381,7 @@ def fir_PrefetchOp : fir_Op<"prefetch", []> {
ConfinedAttr<I32Attr, [IntMinValue<0>, IntMaxValue<3>]> : $localityHint,
UnitAttr : $cacheType);
- let assemblyFormat = "$memref attr-dict `:` type(operands)";
+ let hasCustomAssemblyFormat = 1;
}
def fir_CopyOp : fir_Op<"copy", [DeclareOpInterfaceMethods<MemoryEffectsOpInterface>]> {
diff --git a/flang/lib/Optimizer/Dialect/FIROps.cpp b/flang/lib/Optimizer/Dialect/FIROps.cpp
index 4f97acaa88b7a..20bcbedda7fc9 100644
--- a/flang/lib/Optimizer/Dialect/FIROps.cpp
+++ b/flang/lib/Optimizer/Dialect/FIROps.cpp
@@ -4264,6 +4264,87 @@ void fir::StoreOp::getEffects(
addVolatileMemoryEffects({getMemref().getType()}, effects);
}
+//===----------------------------------------------------------------------===//
+// PrefetchOp
+//===----------------------------------------------------------------------===//
+
+mlir::ParseResult fir::PrefetchOp::parse(mlir::OpAsmParser &parser,
+ mlir::OperationState &result) {
+ mlir::OpAsmParser::UnresolvedOperand memref;
+ // mlir::Type type = parser.getBuilder().getIntegerType(64);
+ if (parser.parseOperand(memref))
+ return mlir::failure();
+
+ if (mlir::succeeded(parser.parseLBrace())) {
+ llvm::StringRef kw;
+ if (parser.parseKeyword(&kw))
+ return mlir::failure();
+
+ if (kw == "read")
+ result.addAttribute("rw", parser.getBuilder().getBoolAttr(false));
+ else if (kw == "write")
+ result.addAttribute("rw", parser.getBuilder().getUnitAttr());
+ else
+ return parser.emitError(parser.getCurrentLocation(),
+ "Expected either read or write keyword");
+
+ if (parser.parseComma())
+ return mlir::failure();
+
+ if (parser.parseKeyword(&kw))
+ return mlir::failure();
+ if (kw == "instruction") {
+ llvm::errs() << "intruc\n";
+ result.addAttribute("cacheType", parser.getBuilder().getBoolAttr(false));
+ } else if (kw == "data") {
+ llvm::errs() << "data\n";
+ result.addAttribute("cacheType", parser.getBuilder().getUnitAttr());
+ } else
+ return parser.emitError(parser.getCurrentLocation(),
+ "Expected either read or write keyword");
+
+ if (parser.parseComma())
+ return mlir::failure();
+
+ if (mlir::succeeded(parser.parseKeyword("localityHint"))) {
+ if (parser.parseEqual())
+ return mlir::failure();
+ mlir::Attribute intAttr;
+ if (parser.parseAttribute(intAttr))
+ return mlir::failure();
+ result.addAttribute("localityHint", intAttr);
+ }
+ if (parser.parseRBrace())
+ return mlir::failure();
+ }
+ mlir::Type type;
+ if (parser.parseColonType(type))
+ return mlir::failure();
+
+ if (parser.resolveOperand(memref, type, result.operands))
+ return mlir::failure();
+ return ::mlir::success();
+}
+
+void fir::PrefetchOp::print(mlir::OpAsmPrinter &p) {
+ p << " ";
+ p.printOperand(getMemref());
+ p << " {";
+ if (getRw())
+ p << "write";
+ else
+ p << "read";
+ p << ", ";
+ if (getCacheType())
+ p << "data";
+ else
+ p << "instruction";
+ p << ", localityHint = ";
+ p << getLocalityHint();
+ p << " : " << getLocalityHintAttr().getType();
+ p << "} : " << getMemref().getType();
+}
+
//===----------------------------------------------------------------------===//
// CopyOp
//===----------------------------------------------------------------------===//
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