atmnpatel updated this revision to Diff 289849.
atmnpatel added a comment.
In Summary:
- I changed the llvm loop metadata name to `mustprogress`, to indicate that
loops with this attribute are required to have side-effects.
- The `mayprogress` function attribute is applied to functions where an
infinite loop is found with a constant conditional.
- The `mustprogress` attribute is applied to loops within a `mayprogress`
function that do not have a constant conditional.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D86841/new/
https://reviews.llvm.org/D86841
Files:
clang/lib/CodeGen/CGLoopInfo.cpp
clang/lib/CodeGen/CGLoopInfo.h
clang/lib/CodeGen/CGStmt.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/test/CodeGen/attr-noprogress.c
clang/test/CodeGen/attr-noprogress.cpp
clang/test/CodeGenCXX/fno-unroll-loops-metadata.cpp
Index: clang/test/CodeGenCXX/fno-unroll-loops-metadata.cpp
===================================================================
--- clang/test/CodeGenCXX/fno-unroll-loops-metadata.cpp
+++ clang/test/CodeGenCXX/fno-unroll-loops-metadata.cpp
@@ -4,7 +4,7 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++11 -emit-llvm -o - %s -O3 -disable-llvm-optzns -fno-unroll-loops | FileCheck --check-prefix=UNROLL_DISABLED_MD %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++11 -emit-llvm -o - %s -O3 -disable-llvm-optzns | FileCheck --check-prefix=NO_UNROLL_MD %s
-// NO_UNROLL_MD-NOT: llvm.loop
+// NO_UNROLL_MD-NOT: llvm.loop.unroll.disable
// Verify unroll.disable metadata is added to while loop with -fno-unroll-loops
// and optlevel > 0.
Index: clang/test/CodeGen/attr-noprogress.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.cpp
@@ -0,0 +1,188 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+int a = 0;
+int b = 0;
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z2f1v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: ret void
+//
+void f1() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @_Z2f2v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: ret void
+//
+void f2() {
+ for (; a == b;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z1Fv(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: br label [[FOR_COND1:%.*]]
+// CHECK: for.cond1:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[FOR_BODY2:%.*]], label [[FOR_END3:%.*]]
+// CHECK: for.body2:
+// CHECK: br label [[FOR_COND1]], !llvm.loop [[LOOP2:!.*]]
+// CHECK: for.end3:
+// CHECK: ret void
+//
+void F() {
+ for (; 1;) {
+ }
+ for (; a == b;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z2w1v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_BODY]]
+//
+void w1() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @_Z2w2v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_COND:%.*]]
+// CHECK: while.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[WHILE_BODY:%.*]], label [[WHILE_END:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_COND]]
+// CHECK: while.end:
+// CHECK: ret void
+//
+void w2() {
+ while (a == b) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z1Wv(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_COND:%.*]]
+// CHECK: while.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[WHILE_BODY:%.*]], label [[WHILE_END:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_COND]], !llvm.loop [[LOOP4:!.*]]
+// CHECK: while.end:
+// CHECK: br label [[WHILE_BODY2:%.*]]
+// CHECK: while.body2:
+// CHECK: br label [[WHILE_BODY2]]
+//
+void W() {
+ while (a == b) {
+ }
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z2d1v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: br i1 true, label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: ret void
+//
+void d1() {
+ do {
+ } while (1);
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @_Z2d2v(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: ret void
+//
+void d2() {
+ do {
+ } while (a == b);
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @_Z1Dv(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: br i1 true, label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: br label [[DO_BODY1:%.*]]
+// CHECK: do.body1:
+// CHECK: br label [[DO_COND2:%.*]]
+// CHECK: do.cond2:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[DO_BODY1]], label [[DO_END3:%.*]], !llvm.loop [[LOOP5:!.*]]
+// CHECK: do.end3:
+// CHECK: ret void
+//
+void D() {
+ do {
+ } while (1);
+ do {
+ } while (a == b);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[GEN3:!.*]]}
+// CHECK: [[GEN3]] = !{!"llvm.loop.mustprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[GEN3]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[GEN3]]}
Index: clang/test/CodeGen/attr-noprogress.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.c
@@ -0,0 +1,188 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+int a = 0;
+int b = 0;
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @f1(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: ret void
+//
+void f1() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @f2(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: ret void
+//
+void f2() {
+ for (; a == b;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @F(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK: br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK: br label [[FOR_COND]]
+// CHECK: for.end:
+// CHECK: br label [[FOR_COND1:%.*]]
+// CHECK: for.cond1:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[FOR_BODY2:%.*]], label [[FOR_END3:%.*]]
+// CHECK: for.body2:
+// CHECK: br label [[FOR_COND1]], !llvm.loop [[LOOP2:!.*]]
+// CHECK: for.end3:
+// CHECK: ret void
+//
+void F() {
+ for (; 1;) {
+ }
+ for (; a == b;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @w1(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_BODY]]
+//
+void w1() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @w2(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_COND:%.*]]
+// CHECK: while.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[WHILE_BODY:%.*]], label [[WHILE_END:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_COND]]
+// CHECK: while.end:
+// CHECK: ret void
+//
+void w2() {
+ while (a == b) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @W(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[WHILE_COND:%.*]]
+// CHECK: while.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[WHILE_BODY:%.*]], label [[WHILE_END:%.*]]
+// CHECK: while.body:
+// CHECK: br label [[WHILE_COND]], !llvm.loop [[LOOP4:!.*]]
+// CHECK: while.end:
+// CHECK: br label [[WHILE_BODY2:%.*]]
+// CHECK: while.body2:
+// CHECK: br label [[WHILE_BODY2]]
+//
+void W() {
+ while (a == b) {
+ }
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @d1(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: br i1 true, label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: ret void
+//
+void d1() {
+ do {
+ } while (1);
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone
+// CHECK-LABEL: @d2(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: ret void
+//
+void d2() {
+ do {
+ } while (a == b);
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone mayprogress
+// CHECK-LABEL: @D(
+// CHECK-NEXT: entry:
+// CHECK-NEXT: br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK: br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK: br i1 true, label [[DO_BODY]], label [[DO_END:%.*]]
+// CHECK: do.end:
+// CHECK: br label [[DO_BODY1:%.*]]
+// CHECK: do.body1:
+// CHECK: br label [[DO_COND2:%.*]]
+// CHECK: do.cond2:
+// CHECK: [[TMP0:%.*]] = load i32, i32* @a, align 4
+// CHECK: [[TMP1:%.*]] = load i32, i32* @b, align 4
+// CHECK: [[CMP:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]]
+// CHECK: br i1 [[CMP]], label [[DO_BODY1]], label [[DO_END3:%.*]], !llvm.loop [[LOOP5:!.*]]
+// CHECK: do.end3:
+// CHECK: ret void
+//
+void D() {
+ do {
+ } while (1);
+ do {
+ } while (a == b);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[GEN3:!.*]]}
+// CHECK: [[GEN3]] = !{!"llvm.loop.mustprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[GEN3]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[GEN3]]}
Index: clang/lib/CodeGen/CodeGenFunction.h
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.h
+++ clang/lib/CodeGen/CodeGenFunction.h
@@ -2071,6 +2071,9 @@
static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor);
+ void StmtIsMayProgressLoop(const Stmt *S);
+ void CompoundStmtContainsMayProgressLoop(const Stmt *S);
+
void EmitConstructorBody(FunctionArgList &Args);
void EmitDestructorBody(FunctionArgList &Args);
void emitImplicitAssignmentOperatorBody(FunctionArgList &Args);
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1141,8 +1141,60 @@
LargestVectorWidth = VecWidth->getVectorWidth();
}
+void CodeGenFunction::StmtIsMayProgressLoop(const Stmt *S) {
+ Expr::EvalResult Result;
+ llvm::ConstantInt *C = nullptr;
+ switch (S->getStmtClass()) {
+ case Stmt::WhileStmtClass: {
+ const WhileStmt &W = cast<WhileStmt>(*S);
+ if (W.getCond()->isEvaluatable(getContext()) &&
+ W.getCond()->EvaluateAsInt(Result, getContext()))
+ C = llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt());
+ break;
+ }
+ case Stmt::DoStmtClass: {
+ const DoStmt &D = cast<DoStmt>(*S);
+ if (D.getCond()->isEvaluatable(getContext()) &&
+ D.getCond()->EvaluateAsInt(Result, getContext()))
+ C = llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt());
+ break;
+ }
+ case Stmt::ForStmtClass: {
+ const ForStmt &F = cast<ForStmt>(*S);
+ if (!F.getCond()) {
+ CurFn->addFnAttr(llvm::Attribute::MayProgress);
+ return;
+ } else {
+ if (F.getCond()->isEvaluatable(getContext()) &&
+ F.getCond()->EvaluateAsInt(Result, getContext()))
+ C = llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt());
+ break;
+ }
+ return;
+ }
+ default:
+ break;
+ }
+
+ if (C && C->isOne() && !CurFn->hasFnAttribute(llvm::Attribute::MayProgress)) {
+ CurFn->addFnAttr(llvm::Attribute::MayProgress);
+ return;
+ }
+}
+
+void CodeGenFunction::CompoundStmtContainsMayProgressLoop(const Stmt *Body) {
+ if (const CompoundStmt *C = dyn_cast<CompoundStmt>(Body)) {
+ for (auto *S : C->body()) {
+ CompoundStmtContainsMayProgressLoop(S);
+ }
+ } else {
+ StmtIsMayProgressLoop(Body);
+ }
+}
+
void CodeGenFunction::EmitFunctionBody(const Stmt *Body) {
incrementProfileCounter(Body);
+ CompoundStmtContainsMayProgressLoop(Body);
if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body))
EmitCompoundStmtWithoutScope(*S);
else
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -22,6 +22,7 @@
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/IR/Attributes.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Intrinsics.h"
@@ -736,11 +737,6 @@
JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
EmitBlock(LoopHeader.getBlock());
- const SourceRange &R = S.getSourceRange();
- LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
- WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
- SourceLocToDebugLoc(R.getEnd()));
-
// Create an exit block for when the condition fails, which will
// also become the break target.
JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
@@ -768,9 +764,17 @@
// while(1) is common, avoid extra exit blocks. Be sure
// to correctly handle break/continue though.
bool EmitBoolCondBranch = true;
- if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
+ bool MustProgress = false;
+ if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) {
if (C->isOne())
EmitBoolCondBranch = false;
+ } else if (CurFn->hasFnAttribute(llvm::Attribute::MayProgress))
+ MustProgress = true;
+
+ const SourceRange &R = S.getSourceRange();
+ LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
+ WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
+ SourceLocToDebugLoc(R.getEnd()), MustProgress);
// As long as the condition is true, go to the loop body.
llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
@@ -838,11 +842,6 @@
EmitBlock(LoopCond.getBlock());
- const SourceRange &R = S.getSourceRange();
- LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
- SourceLocToDebugLoc(R.getBegin()),
- SourceLocToDebugLoc(R.getEnd()));
-
// C99 6.8.5.2: "The evaluation of the controlling expression takes place
// after each execution of the loop body."
@@ -856,9 +855,17 @@
// "do {} while (0)" is common in macros, avoid extra blocks. Be sure
// to correctly handle break/continue though.
bool EmitBoolCondBranch = true;
- if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
+ bool MustProgress = false;
+ if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) {
if (C->isZero())
EmitBoolCondBranch = false;
+ } else if (CurFn->hasFnAttribute(llvm::Attribute::MayProgress))
+ MustProgress = true;
+
+ const SourceRange &R = S.getSourceRange();
+ LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
+ SourceLocToDebugLoc(R.getBegin()),
+ SourceLocToDebugLoc(R.getEnd()), MustProgress);
// As long as the condition is true, iterate the loop.
if (EmitBoolCondBranch) {
@@ -896,10 +903,19 @@
llvm::BasicBlock *CondBlock = Continue.getBlock();
EmitBlock(CondBlock);
+ bool MustProgress = false;
+ if (S.getCond()) {
+ Expr::EvalResult Result;
+ if (!S.getCond()->EvaluateAsInt(Result, getContext()) &&
+ CurFn->hasFnAttribute(llvm::Attribute::MayProgress)) {
+ MustProgress = true;
+ }
+ }
+
const SourceRange &R = S.getSourceRange();
LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
SourceLocToDebugLoc(R.getBegin()),
- SourceLocToDebugLoc(R.getEnd()));
+ SourceLocToDebugLoc(R.getEnd()), MustProgress);
// If the for loop doesn't have an increment we can just use the
// condition as the continue block. Otherwise we'll need to create
Index: clang/lib/CodeGen/CGLoopInfo.h
===================================================================
--- clang/lib/CodeGen/CGLoopInfo.h
+++ clang/lib/CodeGen/CGLoopInfo.h
@@ -75,6 +75,9 @@
/// Value for llvm.loop.pipeline.iicount metadata.
unsigned PipelineInitiationInterval;
+
+ /// Value for whether the loop is required to make progress.
+ bool MustProgress;
};
/// Information used when generating a structured loop.
@@ -205,7 +208,7 @@
void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx,
const clang::CodeGenOptions &CGOpts,
llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc,
- const llvm::DebugLoc &EndLoc);
+ const llvm::DebugLoc &EndLoc, bool MustProgress = false);
/// End the current loop.
void pop();
@@ -272,6 +275,9 @@
StagedAttrs.PipelineInitiationInterval = C;
}
+ /// Set no progress for the next loop pushed.
+ void setMustProgress(bool P) { StagedAttrs.MustProgress = P; }
+
private:
/// Returns true if there is LoopInfo on the stack.
bool hasInfo() const { return !Active.empty(); }
Index: clang/lib/CodeGen/CGLoopInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGLoopInfo.cpp
+++ clang/lib/CodeGen/CGLoopInfo.cpp
@@ -418,10 +418,14 @@
LoopProperties.push_back(EndLoc.getAsMDNode());
}
+ LLVMContext &Ctx = Header->getContext();
+ if (Attrs.MustProgress)
+ LoopProperties.push_back(
+ MDNode::get(Ctx, MDString::get(Ctx, "llvm.loop.mustprogress")));
+
assert(!!AccGroup == Attrs.IsParallel &&
"There must be an access group iff the loop is parallel");
if (Attrs.IsParallel) {
- LLVMContext &Ctx = Header->getContext();
LoopProperties.push_back(MDNode::get(
Ctx, {MDString::get(Ctx, "llvm.loop.parallel_accesses"), AccGroup}));
}
@@ -438,7 +442,7 @@
VectorizePredicateEnable(LoopAttributes::Unspecified), VectorizeWidth(0),
InterleaveCount(0), UnrollCount(0), UnrollAndJamCount(0),
DistributeEnable(LoopAttributes::Unspecified), PipelineDisabled(false),
- PipelineInitiationInterval(0) {}
+ PipelineInitiationInterval(0), MustProgress(false) {}
void LoopAttributes::clear() {
IsParallel = false;
@@ -453,6 +457,7 @@
DistributeEnable = LoopAttributes::Unspecified;
PipelineDisabled = false;
PipelineInitiationInterval = 0;
+ MustProgress = false;
}
LoopInfo::LoopInfo(BasicBlock *Header, const LoopAttributes &Attrs,
@@ -476,7 +481,7 @@
Attrs.UnrollEnable == LoopAttributes::Unspecified &&
Attrs.UnrollAndJamEnable == LoopAttributes::Unspecified &&
Attrs.DistributeEnable == LoopAttributes::Unspecified && !StartLoc &&
- !EndLoc)
+ !EndLoc && !Attrs.MustProgress)
return;
TempLoopID = MDNode::getTemporary(Header->getContext(), None);
@@ -577,8 +582,7 @@
const clang::CodeGenOptions &CGOpts,
ArrayRef<const clang::Attr *> Attrs,
const llvm::DebugLoc &StartLoc,
- const llvm::DebugLoc &EndLoc) {
-
+ const llvm::DebugLoc &EndLoc, bool MustProgress) {
// Identify loop hint attributes from Attrs.
for (const auto *Attr : Attrs) {
const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(Attr);
@@ -755,6 +759,8 @@
}
}
+ setMustProgress(MustProgress);
+
if (CGOpts.OptimizationLevel > 0)
// Disable unrolling for the loop, if unrolling is disabled (via
// -fno-unroll-loops) and no pragmas override the decision.
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