https://github.com/andykaylor updated
https://github.com/llvm/llvm-project/pull/134181
>From 54454e4d52570f29c493c41fc9bf95cbaf9e0886 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Fri, 21 Mar 2025 09:46:27 -0700
Subject: [PATCH 1/4] [CIR] Upstream support for break and continue statements
This adds ClangIR support for break and continue statements in loops.
Because only loops are currently implemented upstream in CIR, only breaks
in loops are supported here, but this same code will work (with minor
changes to the verification and cfg flattening) when switch statements
are upstreamed.
---
.../CIR/Dialect/Builder/CIRBaseBuilder.h | 10 ++
clang/include/clang/CIR/Dialect/IR/CIROps.td | 29 +++++
clang/include/clang/CIR/MissingFeatures.h | 2 -
clang/lib/CIR/CodeGen/CIRGenFunction.h | 2 +
clang/lib/CIR/CodeGen/CIRGenStmt.cpp | 23 ++++
clang/lib/CIR/Dialect/IR/CIRDialect.cpp | 21 +++
.../lib/CIR/Dialect/Transforms/FlattenCFG.cpp | 21 +--
clang/test/CIR/CodeGen/loop.cpp | 122 ++++++++++++++++++
8 files changed, 218 insertions(+), 12 deletions(-)
diff --git a/clang/include/clang/CIR/Dialect/Builder/CIRBaseBuilder.h
b/clang/include/clang/CIR/Dialect/Builder/CIRBaseBuilder.h
index e666be0b25d75..900d78c401ebf 100644
--- a/clang/include/clang/CIR/Dialect/Builder/CIRBaseBuilder.h
+++ b/clang/include/clang/CIR/Dialect/Builder/CIRBaseBuilder.h
@@ -136,6 +136,16 @@ class CIRBaseBuilderTy : public mlir::OpBuilder {
return create<cir::ForOp>(loc, condBuilder, bodyBuilder, stepBuilder);
}
+ /// Create a break operation.
+ cir::BreakOp createBreak(mlir::Location loc) {
+ return create<cir::BreakOp>(loc);
+ }
+
+ /// Create a continue operation.
+ cir::ContinueOp createContinue(mlir::Location loc) {
+ return create<cir::ContinueOp>(loc);
+ }
+
mlir::TypedAttr getConstPtrAttr(mlir::Type type, int64_t value) {
auto valueAttr = mlir::IntegerAttr::get(
mlir::IntegerType::get(type.getContext(), 64), value);
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td
b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 3965372755685..7ddf5e843bde2 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -569,6 +569,35 @@ def YieldOp : CIR_Op<"yield", [ReturnLike, Terminator,
];
}
+//===----------------------------------------------------------------------===//
+// BreakOp
+//===----------------------------------------------------------------------===//
+
+def BreakOp : CIR_Op<"break", [Terminator]> {
+ let summary = "C/C++ `break` statement equivalent";
+ let description = [{
+ The `cir.break` operation is used to cease the control flow to the parent
+ operation, exiting its region's control flow. It is only allowed if it is
+ within a breakable operation (loops and `switch`).
+ }];
+ let assemblyFormat = "attr-dict";
+ let hasVerifier = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// ContinueOp
+//===----------------------------------------------------------------------===//
+
+def ContinueOp : CIR_Op<"continue", [Terminator]> {
+ let summary = "C/C++ `continue` statement equivalent";
+ let description = [{
+ The `cir.continue` operation is used to continue execution to the next
+ iteration of a loop. It is only allowed within `cir.loop` regions.
+ }];
+ let assemblyFormat = "attr-dict";
+ let hasVerifier = 1;
+}
+
//===----------------------------------------------------------------------===//
// ScopeOp
//===----------------------------------------------------------------------===//
diff --git a/clang/include/clang/CIR/MissingFeatures.h
b/clang/include/clang/CIR/MissingFeatures.h
index 3a102d90aba8f..be16b5c063f3b 100644
--- a/clang/include/clang/CIR/MissingFeatures.h
+++ b/clang/include/clang/CIR/MissingFeatures.h
@@ -122,12 +122,10 @@ struct MissingFeatures {
// Future CIR operations
static bool awaitOp() { return false; }
- static bool breakOp() { return false; }
static bool callOp() { return false; }
static bool complexCreateOp() { return false; }
static bool complexImagOp() { return false; }
static bool complexRealOp() { return false; }
- static bool continueOp() { return false; }
static bool ifOp() { return false; }
static bool labelOp() { return false; }
static bool ptrDiffOp() { return false; }
diff --git a/clang/lib/CIR/CodeGen/CIRGenFunction.h
b/clang/lib/CIR/CodeGen/CIRGenFunction.h
index 5cae4d5da9516..c244e3752d7fe 100644
--- a/clang/lib/CIR/CodeGen/CIRGenFunction.h
+++ b/clang/lib/CIR/CodeGen/CIRGenFunction.h
@@ -395,6 +395,8 @@ class CIRGenFunction : public CIRGenTypeCache {
LValue emitBinaryOperatorLValue(const BinaryOperator *e);
+ mlir::LogicalResult emitBreakStmt(const clang::BreakStmt &s);
+ mlir::LogicalResult emitContinueStmt(const clang::ContinueStmt &s);
mlir::LogicalResult emitDoStmt(const clang::DoStmt &s);
/// Emit an expression as an initializer for an object (variable, field,
etc.)
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index b5c1f0ae2a7ef..0c33da6c8722c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -229,6 +229,10 @@ mlir::LogicalResult CIRGenFunction::emitSimpleStmt(const
Stmt *s,
else
emitCompoundStmt(cast<CompoundStmt>(*s));
break;
+ case Stmt::ContinueStmtClass:
+ return emitContinueStmt(cast<ContinueStmt>(*s));
+ case Stmt::BreakStmtClass:
+ return emitBreakStmt(cast<BreakStmt>(*s));
case Stmt::ReturnStmtClass:
return emitReturnStmt(cast<ReturnStmt>(*s));
}
@@ -316,6 +320,25 @@ mlir::LogicalResult CIRGenFunction::emitReturnStmt(const
ReturnStmt &s) {
return mlir::success();
}
+mlir::LogicalResult
+CIRGenFunction::emitContinueStmt(const clang::ContinueStmt &s) {
+ builder.createContinue(getLoc(s.getContinueLoc()));
+
+ // Insert the new block to continue codegen after the continue statement.
+ builder.createBlock(builder.getBlock()->getParent());
+
+ return mlir::success();
+}
+
+mlir::LogicalResult CIRGenFunction::emitBreakStmt(const clang::BreakStmt &s) {
+ builder.createBreak(getLoc(s.getBreakLoc()));
+
+ // Insert the new block to continue codegen after the break statement.
+ builder.createBlock(builder.getBlock()->getParent());
+
+ return mlir::success();
+}
+
mlir::LogicalResult CIRGenFunction::emitForStmt(const ForStmt &s) {
cir::ForOp forOp;
diff --git a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
index 4ace083e3c081..ccbc075ae7d9d 100644
--- a/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
+++ b/clang/lib/CIR/Dialect/IR/CIRDialect.cpp
@@ -151,6 +151,17 @@ void cir::AllocaOp::build(mlir::OpBuilder &odsBuilder,
odsState.addTypes(addr);
}
+//===----------------------------------------------------------------------===//
+// BreakOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::BreakOp::verify() {
+ assert(!cir::MissingFeatures::switchOp());
+ if (!getOperation()->getParentOfType<LoopOpInterface>())
+ return emitOpError("must be within a loop");
+ return success();
+}
+
//===----------------------------------------------------------------------===//
// ConditionOp
//===----------------------------------------------------------------------===//
@@ -241,6 +252,16 @@ OpFoldResult cir::ConstantOp::fold(FoldAdaptor
/*adaptor*/) {
return getValue();
}
+//===----------------------------------------------------------------------===//
+// ContinueOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::ContinueOp::verify() {
+ if (!getOperation()->getParentOfType<LoopOpInterface>())
+ return emitOpError("must be within a loop");
+ return success();
+}
+
//===----------------------------------------------------------------------===//
// CastOp
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Dialect/Transforms/FlattenCFG.cpp
b/clang/lib/CIR/Dialect/Transforms/FlattenCFG.cpp
index 52f4b2241505d..b49c5ffd35c00 100644
--- a/clang/lib/CIR/Dialect/Transforms/FlattenCFG.cpp
+++ b/clang/lib/CIR/Dialect/Transforms/FlattenCFG.cpp
@@ -148,23 +148,24 @@ class CIRLoopOpInterfaceFlattening
// driver to customize the order that operations are visited.
// Lower continue statements.
+ mlir::Block *dest = (step ? step : cond);
op.walkBodySkippingNestedLoops([&](mlir::Operation *op) {
- // When continue ops are supported, there will be a check for them here
- // and a call to lowerTerminator(). The call to `advance()` handles the
- // case where this is not a continue op.
- assert(!cir::MissingFeatures::continueOp());
- return mlir::WalkResult::advance();
+ if (!isa<cir::ContinueOp>(op))
+ return mlir::WalkResult::advance();
+
+ lowerTerminator(op, dest, rewriter);
+ return mlir::WalkResult::skip();
});
// Lower break statements.
assert(!cir::MissingFeatures::switchOp());
walkRegionSkipping<cir::LoopOpInterface>(
op.getBody(), [&](mlir::Operation *op) {
- // When break ops are supported, there will be a check for them here
- // and a call to lowerTerminator(). The call to `advance()` handles
- // the case where this is not a break op.
- assert(!cir::MissingFeatures::breakOp());
- return mlir::WalkResult::advance();
+ if (!isa<cir::BreakOp>(op))
+ return mlir::WalkResult::advance();
+
+ lowerTerminator(op, exit, rewriter);
+ return mlir::WalkResult::skip();
});
// Lower optional body region yield.
diff --git a/clang/test/CIR/CodeGen/loop.cpp b/clang/test/CIR/CodeGen/loop.cpp
index a950460e8838d..46fa66e2fc7aa 100644
--- a/clang/test/CIR/CodeGen/loop.cpp
+++ b/clang/test/CIR/CodeGen/loop.cpp
@@ -265,3 +265,125 @@ void test_empty_while_true() {
// OGCG: br label %[[WHILE_BODY:.*]]
// OGCG: [[WHILE_BODY]]:
// OGCG: ret void
+
+void unreachable_after_continue() {
+ for (;;) {
+ continue;
+ int x = 1;
+ }
+}
+
+// CIR: cir.func @unreachable_after_continue
+// CIR: cir.scope {
+// CIR: cir.for : cond {
+// CIR: %[[TRUE:.*]] = cir.const #true
+// CIR: cir.condition(%[[TRUE]])
+// CIR: } body {
+// CIR: cir.scope {
+// CIR: %[[X:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["x", init]
{alignment = 4 : i64}
+// CIR: cir.continue
+// CIR: ^bb1: // no predecessors
+// CIR: %[[ONE:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store %[[ONE]], %[[X]] : !s32i, !cir.ptr<!s32i>
+// CIR: cir.yield
+// CIR: }
+// CIR: cir.yield
+// CIR: } step {
+// CIR: cir.yield
+// CIR: }
+// CIR: }
+// CIR: cir.return
+// CIR: }
+
+// LLVM: define void @unreachable_after_continue()
+// LLVM: %[[X:.*]] = alloca i32, i64 1, align 4
+// LLVM: br label %[[LABEL1:.*]]
+// LLVM: [[LABEL1]]:
+// LLVM: br label %[[LABEL2:.*]]
+// LLVM: [[LABEL2]]:
+// LLVM: br i1 true, label %[[LABEL3:.*]], label %[[LABEL8:.*]]
+// LLVM: [[LABEL3]]:
+// LLVM: br label %[[LABEL4:.*]]
+// LLVM: [[LABEL4]]:
+// LLVM: br label %[[LABEL7:.*]]
+// LLVM: [[LABEL5:.*]]:
+// LLVM-SAME: ; No predecessors!
+// LLVM: store i32 1, ptr %[[X]], align 4
+// LLVM: br label %[[LABEL6:.*]]
+// LLVM: [[LABEL6]]:
+// LLVM: br label %[[LABEL7:.*]]
+// LLVM: [[LABEL7]]:
+// LLVM: br label %[[LABEL2]]
+// LLVM: [[LABEL8]]:
+// LLVM: br label %[[LABEL9:]]
+// LLVM: [[LABEL9]]:
+// LLVM: ret void
+
+// OGCG: define{{.*}} void @_Z26unreachable_after_continuev()
+// OGCG: entry:
+// OGCG: %[[X:.*]] = alloca i32, align 4
+// OGCG: br label %[[FOR_COND:.*]]
+// OGCG: [[FOR_COND]]:
+// OGCG: br label %[[FOR_COND]]
+
+void unreachable_after_break() {
+ for (;;) {
+ break;
+ int x = 1;
+ }
+}
+
+// CIR: cir.func @unreachable_after_break
+// CIR: cir.scope {
+// CIR: cir.for : cond {
+// CIR: %[[TRUE:.*]] = cir.const #true
+// CIR: cir.condition(%[[TRUE]])
+// CIR: } body {
+// CIR: cir.scope {
+// CIR: %[[X:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["x", init]
{alignment = 4 : i64}
+// CIR: cir.break
+// CIR: ^bb1: // no predecessors
+// CIR: %[[ONE:.*]] = cir.const #cir.int<1> : !s32i
+// CIR: cir.store %[[ONE]], %[[X]] : !s32i, !cir.ptr<!s32i>
+// CIR: cir.yield
+// CIR: }
+// CIR: cir.yield
+// CIR: } step {
+// CIR: cir.yield
+// CIR: }
+// CIR: }
+// CIR: cir.return
+// CIR: }
+
+// LLVM: define void @unreachable_after_break()
+// LLVM: %[[X:.*]] = alloca i32, i64 1, align 4
+// LLVM: br label %[[LABEL1:.*]]
+// LLVM: [[LABEL1]]:
+// LLVM: br label %[[LABEL2:.*]]
+// LLVM: [[LABEL2]]:
+// LLVM: br i1 true, label %[[LABEL3:.*]], label %[[LABEL8:.*]]
+// LLVM: [[LABEL3]]:
+// LLVM: br label %[[LABEL4:.*]]
+// LLVM: [[LABEL4]]:
+// LLVM: br label %[[LABEL8]]
+// LLVM: [[LABEL5:.*]]:
+// LLVM-SAME: ; No predecessors!
+// LLVM: store i32 1, ptr %[[X]], align 4
+// LLVM: br label %[[LABEL6:.*]]
+// LLVM: [[LABEL6]]:
+// LLVM: br label %[[LABEL7:.*]]
+// LLVM: [[LABEL7]]:
+// LLVM: br label %[[LABEL2]]
+// LLVM: [[LABEL8]]:
+// LLVM: br label %[[LABEL9:]]
+// LLVM: [[LABEL9]]:
+// LLVM: ret void
+
+// OGCG: define{{.*}} void @_Z23unreachable_after_breakv()
+// OGCG: entry:
+// OGCG: %[[X:.*]] = alloca i32, align 4
+// OGCG: br label %[[FOR_COND:.*]]
+// OGCG: [[FOR_COND]]:
+// OGCG: br label %[[FOR_END:.*]]
+// OGCG: [[FOR_END]]:
+// OGCG: ret void
>From 25bca23ab79f1db706801092f08986860c0040b5 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Thu, 3 Apr 2025 16:43:36 -0700
Subject: [PATCH 2/4] Address review feedback
---
clang/include/clang/CIR/Dialect/IR/CIROps.td | 25 ++++++++++----------
clang/lib/CIR/CodeGen/CIRGenStmt.cpp | 13 +++++-----
2 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td
b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 7ddf5e843bde2..cf27653deb2a3 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -477,7 +477,7 @@ def ConditionOp : CIR_Op<"condition", [
`cir.bool` operand and, depending on its value, may branch to different
regions:
- - When in the `cond` region of a `cir.loop`, it continues the loop
+ - When in the `cond` region of a loop, it continues the loop
if true, or exits it if false.
- When in the `ready` region of a `cir.await`, it branches to the `resume`
region when true, and to the `suspend` region when false.
@@ -485,12 +485,12 @@ def ConditionOp : CIR_Op<"condition", [
Example:
```mlir
- cir.loop for(cond : {
- cir.condition(%arg0) // Branches to `step` region or exits.
- }, step : {
- [...]
- }) {
- [...]
+ cir.for cond {
+ cir.condition(%val) // Branches to `step` region or exits.
+ } body {
+ cir.yield
+ } step {
+ cir.yield
}
cir.await(user, ready : {
@@ -576,9 +576,9 @@ def YieldOp : CIR_Op<"yield", [ReturnLike, Terminator,
def BreakOp : CIR_Op<"break", [Terminator]> {
let summary = "C/C++ `break` statement equivalent";
let description = [{
- The `cir.break` operation is used to cease the control flow to the parent
- operation, exiting its region's control flow. It is only allowed if it is
- within a breakable operation (loops and `switch`).
+ The `cir.break` operation is used to cease the execution of the current
+ loop or switch and transfer control to the parent operation. It is only
+ allowed within a breakable operations (loops and switches).
}];
let assemblyFormat = "attr-dict";
let hasVerifier = 1;
@@ -591,8 +591,9 @@ def BreakOp : CIR_Op<"break", [Terminator]> {
def ContinueOp : CIR_Op<"continue", [Terminator]> {
let summary = "C/C++ `continue` statement equivalent";
let description = [{
- The `cir.continue` operation is used to continue execution to the next
- iteration of a loop. It is only allowed within `cir.loop` regions.
+ The `cir.continue` operation is used to end execution of the current
+ iteration of a loop and resume execution beginning at the next iteration.
+ It is only allowed within loop regions.
}];
let assemblyFormat = "attr-dict";
let hasVerifier = 1;
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index 0c33da6c8722c..97710719e15d3 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -56,6 +56,13 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
return mlir::success();
switch (s->getStmtClass()) {
+ case Stmt::BreakStmtClass:
+ case Stmt::CompoundStmtClass:
+ case Stmt::ContinueStmtClass:
+ case Stmt::DeclStmtClass:
+ case Stmt::ReturnStmtClass:
+ llvm_unreachable("should have emitted these statements as simple");
+
#define STMT(Type, Base)
#define ABSTRACT_STMT(Op)
@@ -88,13 +95,9 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
case Stmt::SEHFinallyStmtClass:
case Stmt::MSDependentExistsStmtClass:
case Stmt::NullStmtClass:
- case Stmt::CompoundStmtClass:
- case Stmt::DeclStmtClass:
case Stmt::LabelStmtClass:
case Stmt::AttributedStmtClass:
case Stmt::GotoStmtClass:
- case Stmt::BreakStmtClass:
- case Stmt::ContinueStmtClass:
case Stmt::DefaultStmtClass:
case Stmt::CaseStmtClass:
case Stmt::SEHLeaveStmtClass:
@@ -106,7 +109,6 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
case Stmt::CXXTryStmtClass:
case Stmt::CXXForRangeStmtClass:
case Stmt::IndirectGotoStmtClass:
- case Stmt::ReturnStmtClass:
case Stmt::GCCAsmStmtClass:
case Stmt::MSAsmStmtClass:
case Stmt::OMPParallelDirectiveClass:
@@ -219,7 +221,6 @@ mlir::LogicalResult CIRGenFunction::emitSimpleStmt(const
Stmt *s,
bool useCurrentScope) {
switch (s->getStmtClass()) {
default:
- // Only compound and return statements are supported right now.
return mlir::failure();
case Stmt::DeclStmtClass:
return emitDeclStmt(cast<DeclStmt>(*s));
>From 8f517fa5f6c967591a8d71641f3ddf76f1358151 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Thu, 3 Apr 2025 17:51:53 -0700
Subject: [PATCH 3/4] Fix formatting
---
clang/lib/CIR/CodeGen/CIRGenStmt.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index 97710719e15d3..00d33e7feddff 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -63,7 +63,6 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
case Stmt::ReturnStmtClass:
llvm_unreachable("should have emitted these statements as simple");
-
#define STMT(Type, Base)
#define ABSTRACT_STMT(Op)
#define EXPR(Type, Base) case Stmt::Type##Class:
>From 927f5bc24c79a9f81a36553eed42065e8b880c28 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Fri, 4 Apr 2025 14:40:10 -0700
Subject: [PATCH 4/4] Wording change in documentation
---
clang/include/clang/CIR/Dialect/IR/CIROps.td | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td
b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index cf27653deb2a3..6030f65c1fcaa 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -576,8 +576,8 @@ def YieldOp : CIR_Op<"yield", [ReturnLike, Terminator,
def BreakOp : CIR_Op<"break", [Terminator]> {
let summary = "C/C++ `break` statement equivalent";
let description = [{
- The `cir.break` operation is used to cease the execution of the current
- loop or switch and transfer control to the parent operation. It is only
+ The `cir.break` operation is used to cease the execution of the current
loop
+ or switch operation and transfer control to the parent operation. It is
only
allowed within a breakable operations (loops and switches).
}];
let assemblyFormat = "attr-dict";
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