https://github.com/farzonl created
https://github.com/llvm/llvm-project/pull/93879
- `Attr.td` - Define the HLSL loop attribute hints (unroll and loop)
- `AttrDocs.td` - Add documentation for unroll and loop
- `CGLoopInfo.cpp` - Add codegen for HLSL unroll that maps to clang unroll
expectations
- `ParseStmt.cpp` - For statements if HLSL define DeclSpecAttrs via
MaybeParseMicrosoftAttributes
- `SemaStmtAttr.cpp` - Add the HLSL loop unroll handeling
resolves ##70114
>From 6c92c23bd62c9ff262e035a135bb4bfac3406f3a Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlo...@microsoft.com>
Date: Thu, 30 May 2024 13:51:35 -0400
Subject: [PATCH] [HLSL] add loop unroll - `Attr.td` - Define the HLSL loop
attribute hints (unroll and loop) - `AttrDocs.td` - Add documentation for
unroll and loop - `CGLoopInfo.cpp` - Add codegen for HLSL unroll that maps to
clang unroll expectations - `ParseStmt.cpp` - For statements if HLSL define
DeclSpecAttrs via MaybeParseMicrosoftAttributes - `SemaStmtAttr.cpp` - Add
the HLSL loop unroll handeling
---
clang/include/clang/Basic/Attr.td | 13 ++++
clang/include/clang/Basic/AttrDocs.td | 47 +++++++++++
clang/lib/CodeGen/CGLoopInfo.cpp | 15 +++-
clang/lib/Parse/ParseStmt.cpp | 11 ++-
clang/lib/Sema/SemaStmtAttr.cpp | 29 +++++++
clang/test/CodeGenHLSL/loops/unroll.hlsl | 99 ++++++++++++++++++++++++
6 files changed, 208 insertions(+), 6 deletions(-)
create mode 100644 clang/test/CodeGenHLSL/loops/unroll.hlsl
diff --git a/clang/include/clang/Basic/Attr.td
b/clang/include/clang/Basic/Attr.td
index 2665b7353ca4a..e319db08ba168 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -4114,6 +4114,19 @@ def LoopHint : Attr {
let HasCustomParsing = 1;
}
+/// The HLSL loop attributes
+def HLSLLoopHint: StmtAttr {
+ /// [unroll(directive)]
+ /// [loop]
+ let Spellings = [Microsoft<"unroll">, Microsoft<"loop">];
+ let Args = [UnsignedArgument<"directive">];
+ let Subjects = SubjectList<[ForStmt, WhileStmt, DoStmt],
+ ErrorDiag, "'for', 'while', and 'do'
statements">;
+ let LangOpts = [HLSL];
+ let Documentation = [HLSLLoopHintDocs, HLSLUnrollHintDocs];
+ let HasCustomParsing = 1;
+}
+
def CapturedRecord : InheritableAttr {
// This attribute has no spellings as it is only ever created implicitly.
let Spellings = [];
diff --git a/clang/include/clang/Basic/AttrDocs.td
b/clang/include/clang/Basic/AttrDocs.td
index a313e811c9d21..d84af9402d6db 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -7342,6 +7342,53 @@ where shaders must be compiled into a library and linked
at runtime.
}];
}
+def HLSLLoopHintDocs : Documentation {
+ let Category = DocCatStmt;
+ let Heading = "#[loop]";
+ let Content = [{
+The ``[loop]`` directive allows loop optimization hints to be
+specified for the subsequent loop. The directive allows unrolling to
+be disabled and is not compatible with [unroll(x)].
+
+Specifying the parameter, ``[loop]``, directs the
+unroller to not unroll the loop.
+
+.. code-block:: hlsl
+
+ [loop]
+ for (...) {
+ ...
+ }
+
+See `hlsl loop extensions
+<https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-for>`_
+for details.
+ }];
+}
+
+def HLSLUnrollHintDocs : Documentation {
+ let Category = DocCatStmt;
+ let Heading = "[unroll(x)]";
+ let Content = [{
+Loop unrolling optimization hints can be specified with ``[unroll(x)]``
+. The attribute is placed immediately before a for, while,
+or do-while.
+Specifying the parameter, ``[unroll(_value_)]``, directs the
+unroller to unroll the loop ``_value_`` times. Note: [unroll(x)] is not
compatible with [loop].
+
+.. code-block:: hlsl
+
+ [unroll(4)]
+ for (...) {
+ ...
+ }
+See
+`hlsl loop extensions
+<https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-for>`_
+for details.
+ }];
+}
+
def ClangRandomizeLayoutDocs : Documentation {
let Category = DocCatDecl;
let Heading = "randomize_layout, no_randomize_layout";
diff --git a/clang/lib/CodeGen/CGLoopInfo.cpp b/clang/lib/CodeGen/CGLoopInfo.cpp
index 0d4800b90a2f2..6b886bd6b6d2c 100644
--- a/clang/lib/CodeGen/CGLoopInfo.cpp
+++ b/clang/lib/CodeGen/CGLoopInfo.cpp
@@ -612,9 +612,9 @@ void LoopInfoStack::push(BasicBlock *Header,
clang::ASTContext &Ctx,
const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(Attr);
const OpenCLUnrollHintAttr *OpenCLHint =
dyn_cast<OpenCLUnrollHintAttr>(Attr);
-
+ const HLSLLoopHintAttr *HLSLLoopHint = dyn_cast<HLSLLoopHintAttr>(Attr);
// Skip non loop hint attributes
- if (!LH && !OpenCLHint) {
+ if (!LH && !OpenCLHint && !HLSLLoopHint) {
continue;
}
@@ -635,6 +635,17 @@ void LoopInfoStack::push(BasicBlock *Header,
clang::ASTContext &Ctx,
Option = LoopHintAttr::UnrollCount;
State = LoopHintAttr::Numeric;
}
+ } else if (HLSLLoopHint) {
+ ValueInt = HLSLLoopHint->getDirective();
+ if (HLSLLoopHint->getSemanticSpelling() ==
+ HLSLLoopHintAttr::Spelling::Microsoft_unroll) {
+ if (ValueInt == 0)
+ State = LoopHintAttr::Enable;
+ if (ValueInt > 0) {
+ Option = LoopHintAttr::UnrollCount;
+ State = LoopHintAttr::Numeric;
+ }
+ }
} else if (LH) {
auto *ValueExpr = LH->getValue();
if (ValueExpr) {
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index c25203243ee49..b8a717820c418 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -114,18 +114,21 @@ Parser::ParseStatementOrDeclaration(StmtVector &Stmts,
// here because we don't want to allow arbitrary orderings.
ParsedAttributes CXX11Attrs(AttrFactory);
MaybeParseCXX11Attributes(CXX11Attrs, /*MightBeObjCMessageSend*/ true);
- ParsedAttributes GNUAttrs(AttrFactory);
+ ParsedAttributes DeclSpecAttrs(AttrFactory);
if (getLangOpts().OpenCL)
- MaybeParseGNUAttributes(GNUAttrs);
+ MaybeParseGNUAttributes(DeclSpecAttrs);
+
+ if (getLangOpts().HLSL)
+ MaybeParseMicrosoftAttributes(DeclSpecAttrs);
StmtResult Res = ParseStatementOrDeclarationAfterAttributes(
- Stmts, StmtCtx, TrailingElseLoc, CXX11Attrs, GNUAttrs);
+ Stmts, StmtCtx, TrailingElseLoc, CXX11Attrs, DeclSpecAttrs);
MaybeDestroyTemplateIds();
// Attributes that are left should all go on the statement, so concatenate
the
// two lists.
ParsedAttributes Attrs(AttrFactory);
- takeAndConcatenateAttrs(CXX11Attrs, GNUAttrs, Attrs);
+ takeAndConcatenateAttrs(CXX11Attrs, DeclSpecAttrs, Attrs);
assert((Attrs.empty() || Res.isInvalid() || Res.isUsable()) &&
"attributes on empty statement");
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 6f538ed55cb72..35a20c113f628 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -16,6 +16,7 @@
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
+#include "clang/Sema/ParsedAttr.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "llvm/ADT/StringExtras.h"
@@ -584,6 +585,32 @@ static Attr *handleOpenCLUnrollHint(Sema &S, Stmt *St,
const ParsedAttr &A,
return ::new (S.Context) OpenCLUnrollHintAttr(S.Context, A, UnrollFactor);
}
+static Attr *handleHLSLLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A,
+ SourceRange Range) {
+ unsigned UnrollFactor = 0;
+ if (A.getNumArgs() == 1) {
+ Expr *E = A.getArgAsExpr(0);
+ std::optional<llvm::APSInt> ArgVal;
+
+ if (!(ArgVal = E->getIntegerConstantExpr(S.Context))) {
+ S.Diag(A.getLoc(), diag::err_attribute_argument_type)
+ << A << AANT_ArgumentIntegerConstant << E->getSourceRange();
+ return nullptr;
+ }
+
+ int Val = ArgVal->getSExtValue();
+ if (Val <= 0) {
+ S.Diag(A.getRange().getBegin(),
+ diag::err_attribute_requires_positive_integer)
+ << A << /* positive */ 0;
+ return nullptr;
+ }
+ UnrollFactor = static_cast<unsigned>(Val);
+ }
+
+ return ::new (S.Context) HLSLLoopHintAttr(S.Context, A, UnrollFactor);
+}
+
static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
SourceRange Range) {
if (A.isInvalid() || A.getKind() == ParsedAttr::IgnoredAttribute)
@@ -618,6 +645,8 @@ static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const
ParsedAttr &A,
return handleFallThroughAttr(S, St, A, Range);
case ParsedAttr::AT_LoopHint:
return handleLoopHintAttr(S, St, A, Range);
+ case ParsedAttr::AT_HLSLLoopHint:
+ return handleHLSLLoopHintAttr(S, St, A, Range);
case ParsedAttr::AT_OpenCLUnrollHint:
return handleOpenCLUnrollHint(S, St, A, Range);
case ParsedAttr::AT_Suppress:
diff --git a/clang/test/CodeGenHLSL/loops/unroll.hlsl
b/clang/test/CodeGenHLSL/loops/unroll.hlsl
new file mode 100644
index 0000000000000..0ebe5b0e847e4
--- /dev/null
+++ b/clang/test/CodeGenHLSL/loops/unroll.hlsl
@@ -0,0 +1,99 @@
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN: dxil-pc-shadermodel6.3-library %s -emit-llvm -o - | FileCheck %s
+
+/*** for ***/
+void for_count()
+{
+// CHECK-LABEL: for_count
+ [unroll(8)]
+ for( int i = 0; i < 1000; ++i);
+// CHECK: br label %{{.*}}, !llvm.loop ![[FOR_DISTINCT:.*]]
+}
+
+void for_disable()
+{
+// CHECK-LABEL: for_disable
+ [loop]
+ for( int i = 0; i < 1000; ++i);
+// CHECK: br label %{{.*}}, !llvm.loop ![[FOR_DISABLE:.*]]
+}
+
+void for_enable()
+{
+// CHECK-LABEL: for_enable
+ [unroll]
+ for( int i = 0; i < 1000; ++i);
+// CHECK: br label %{{.*}}, !llvm.loop ![[FOR_ENABLE:.*]]
+}
+
+/*** while ***/
+void while_count()
+{
+// CHECK-LABEL: while_count
+ int i = 1000;
+ [unroll(4)]
+ while(i-->0);
+// CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_DISTINCT:.*]]
+}
+
+void while_disable()
+{
+// CHECK-LABEL: while_disable
+ int i = 1000;
+ [loop]
+ while(i-->0);
+// CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_DISABLE:.*]]
+}
+
+void while_enable()
+{
+// CHECK-LABEL: while_enable
+ int i = 1000;
+ [unroll]
+ while(i-->0);
+// CHECK: br label %{{.*}}, !llvm.loop ![[WHILE_ENABLE:.*]]
+}
+
+/*** do ***/
+void do_count()
+{
+// CHECK-LABEL: do_count
+ int i = 1000;
+ [unroll(16)]
+ do {} while(i--> 0);
+// CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop
![[DO_DISTINCT:.*]]
+}
+
+void do_disable()
+{
+// CHECK-LABEL: do_disable
+ int i = 1000;
+ [loop]
+ do {} while(i--> 0);
+// CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop
![[DO_DISABLE:.*]]
+}
+
+void do_enable()
+{
+// CHECK-LABEL: do_enable
+ int i = 1000;
+ [unroll]
+ do {} while(i--> 0);
+// CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !llvm.loop
![[DO_ENABLE:.*]]
+}
+
+
+// CHECK: ![[FOR_DISTINCT]] = distinct !{![[FOR_DISTINCT]],
![[FOR_COUNT:.*]]}
+// CHECK: ![[FOR_COUNT]] = !{!"llvm.loop.unroll.count", i32 8}
+// CHECK: ![[FOR_DISABLE]] = distinct !{![[FOR_DISABLE]], ![[DISABLE:.*]]}
+// CHECK: ![[DISABLE]] = !{!"llvm.loop.unroll.disable"}
+// CHECK: ![[FOR_ENABLE]] = distinct !{![[FOR_ENABLE]], ![[ENABLE:.*]]}
+// CHECK: ![[ENABLE]] = !{!"llvm.loop.unroll.enable"}
+// CHECK: ![[WHILE_DISTINCT]] = distinct !{![[WHILE_DISTINCT]],
![[WHILE_COUNT:.*]]}
+// CHECK: ![[WHILE_COUNT]] = !{!"llvm.loop.unroll.count", i32 4}
+// CHECK: ![[WHILE_DISABLE]] = distinct !{![[WHILE_DISABLE]], ![[DISABLE]]}
+// CHECK: ![[WHILE_ENABLE]] = distinct !{![[WHILE_ENABLE]],
![[ENABLE]]}
+// CHECK: ![[DO_DISTINCT]] = distinct !{![[DO_DISTINCT]],
![[DO_COUNT:.*]]}
+// CHECK: ![[DO_COUNT]] = !{!"llvm.loop.unroll.count", i32 16}
+// CHECK: ![[DO_DISABLE]] = distinct !{![[DO_DISABLE]], ![[DISABLE]]}
+// CHECK: ![[DO_ENABLE]] = distinct !{![[DO_ENABLE]],
![[ENABLE]]}
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