[CIR] Upstream StackSave and StackRestoreOp #136426

AmrDeveloper · 2025-04-19T12:28:00Z

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

llvmbot · 2025-04-19T12:28:37Z

@llvm/pr-subscribers-clangir

Author: Amr Hesham (AmrDeveloper)

Changes

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

Full diff: https://github.com/llvm/llvm-project/pull/136426.diff

5 Files Affected:

(modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+42)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+18)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h (+20)
(added) clang/test/CIR/IR/stack-save-restore.cir (+23)
(added) clang/test/CIR/Lowering/stack-save-restore.cir (+19)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 5ba4b33dc1a12..2b48aac97e7ef 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -1419,6 +1419,48 @@ def CallOp : CIR_CallOpBase<"call", [NoRegionArguments]> {
     }]>];
 }
 
+//===----------------------------------------------------------------------===//
+// StackSave & StackRestoreOp
+//===----------------------------------------------------------------------===//
+
+def StackSaveOp : CIR_Op<"stack_save"> {
+  let summary = "remembers the current state of the function stack";
+  let description = [{
+    Remembers the current state of the function stack. Returns a pointer
+    that later can be passed into cir.stack_restore.
+    Useful for implementing language features like variable length arrays.
+
+    ```mlir
+    %0 = cir.stack_save : <!u8i>
+    ```
+  }];
+
+  let results = (outs CIR_PointerType:$result);
+  let assemblyFormat = "attr-dict `:` qualified(type($result))";
+}
+
+def StackRestoreOp : CIR_Op<"stack_restore"> {
+  let summary = "restores the state of the function stack";
+  let description = [{
+    Restore the state of the function stack to the state it was
+    in when the corresponding cir.stack_save executed.
+    Useful for implementing language features like variable length arrays.
+
+    ```mlir
+    %0 = cir.alloca !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>, ["saved_stack"] {alignment = 8 : i64}
+    %1 = cir.stack_save : <!u8i>
+    cir.store %1, %0 : !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>
+    %2 = cir.load %0 : !cir.ptr<!cir.ptr<!u8i>>, !cir.ptr<!u8i>
+    cir.stack_restore %2 : !cir.ptr<!u8i>
+    ```
+  }];
+
+  let arguments = (ins CIR_PointerType:$ptr);
+  let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
+
+  let llvmOp = "StackRestoreOp";
+}
+
 //===----------------------------------------------------------------------===//
 // UnreachableOp
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 8c4a67258df3f..0673b1543d91e 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1467,6 +1467,8 @@ void ConvertCIRToLLVMPass::runOnOperation() {
                CIRToLLVMConstantOpLowering,
                CIRToLLVMFuncOpLowering,
                CIRToLLVMGetGlobalOpLowering,
+               CIRToLLVMStackSaveOpLowering,
+               CIRToLLVMStackRestoreOpLowering,
                CIRToLLVMTrapOpLowering,
                CIRToLLVMUnaryOpLowering
       // clang-format on
@@ -1512,6 +1514,22 @@ mlir::LogicalResult CIRToLLVMTrapOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMStackSaveOpLowering::matchAndRewrite(
+    cir::StackSaveOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  const mlir::Type ptrTy = getTypeConverter()->convertType(op.getType());
+  rewriter.replaceOpWithNewOp<mlir::LLVM::StackSaveOp>(op, ptrTy);
+  return mlir::success();
+}
+
+mlir::LogicalResult CIRToLLVMStackRestoreOpLowering::matchAndRewrite(
+    cir::StackRestoreOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  rewriter.replaceOpWithNewOp<mlir::LLVM::StackRestoreOp>(
+      op, adaptor.getOperands().front());
+  return mlir::success();
+}
+
 std::unique_ptr<mlir::Pass> createConvertCIRToLLVMPass() {
   return std::make_unique<ConvertCIRToLLVMPass>();
 }
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
index 1de6c9c56b485..a7c2704e13fe6 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -242,6 +242,26 @@ class CIRToLLVMPtrStrideOpLowering
   matchAndRewrite(cir::PtrStrideOp op, OpAdaptor,
                   mlir::ConversionPatternRewriter &) const override;
 };
+
+class CIRToLLVMStackSaveOpLowering
+    : public mlir::OpConversionPattern<cir::StackSaveOp> {
+public:
+  using mlir::OpConversionPattern<cir::StackSaveOp>::OpConversionPattern;
+  mlir::LogicalResult
+  matchAndRewrite(cir::StackSaveOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
+class CIRToLLVMStackRestoreOpLowering
+    : public mlir::OpConversionPattern<cir::StackRestoreOp> {
+public:
+  using OpConversionPattern<cir::StackRestoreOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::StackRestoreOp op, OpAdaptor adaptor,
+                  mlir::ConversionPatternRewriter &rewriter) const override;
+};
+
 } // namespace direct
 } // namespace cir
 
diff --git a/clang/test/CIR/IR/stack-save-restore.cir b/clang/test/CIR/IR/stack-save-restore.cir
new file mode 100644
index 0000000000000..f6027258786df
--- /dev/null
+++ b/clang/test/CIR/IR/stack-save-restore.cir
@@ -0,0 +1,23 @@
+// Test the CIR operations can parse and print correctly (roundtrip)
+
+// RUN: cir-opt %s | cir-opt | FileCheck %s
+
+!u8i = !cir.int<u, 8>
+
+module  {
+  cir.func @stack_save_restore() {
+    %0 = cir.stack_save : !cir.ptr<!u8i>
+    cir.stack_restore %0 : !cir.ptr<!u8i>
+    cir.return
+  }
+}
+
+//CHECK: module  {
+
+//CHECK-NEXT: cir.func @stack_save_restore() {
+//CHECK-NEXT:   %0 = cir.stack_save : !cir.ptr<!u8i>
+//CHECK-NEXT:   cir.stack_restore %0 : !cir.ptr<!u8i>
+//CHECK-NEXT:   cir.return
+//CHECK-NEXT: }
+
+//CHECK-NEXT: }
diff --git a/clang/test/CIR/Lowering/stack-save-restore.cir b/clang/test/CIR/Lowering/stack-save-restore.cir
new file mode 100644
index 0000000000000..ad9dee66b53f5
--- /dev/null
+++ b/clang/test/CIR/Lowering/stack-save-restore.cir
@@ -0,0 +1,19 @@
+// RUN: cir-opt %s -cir-to-llvm -o - | FileCheck %s -check-prefix=MLIR
+
+!u8i = !cir.int<u, 8>
+
+module  {
+  cir.func @stack_save() {
+    %0 = cir.stack_save : !cir.ptr<!u8i>
+    cir.stack_restore %0 : !cir.ptr<!u8i>
+    cir.return
+  }
+}
+
+//      MLIR: module {
+// MLIR-NEXT:  llvm.func @stack_save
+// MLIR-NEXT:    %0 = llvm.intr.stacksave : !llvm.ptr
+// MLIR-NEXT:    llvm.intr.stackrestore %0 : !llvm.ptr
+// MLIR-NEXT:    llvm.return
+// MLIR-NEXT:  }
+// MLIR-NEXT: }

llvmbot · 2025-04-19T12:28:37Z

@llvm/pr-subscribers-clang

Author: Amr Hesham (AmrDeveloper)

Changes

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

Full diff: https://github.com/llvm/llvm-project/pull/136426.diff

5 Files Affected:

(modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+42)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+18)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h (+20)
(added) clang/test/CIR/IR/stack-save-restore.cir (+23)
(added) clang/test/CIR/Lowering/stack-save-restore.cir (+19)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 5ba4b33dc1a12..2b48aac97e7ef 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -1419,6 +1419,48 @@ def CallOp : CIR_CallOpBase<"call", [NoRegionArguments]> {
     }]>];
 }
 
+//===----------------------------------------------------------------------===//
+// StackSave & StackRestoreOp
+//===----------------------------------------------------------------------===//
+
+def StackSaveOp : CIR_Op<"stack_save"> {
+  let summary = "remembers the current state of the function stack";
+  let description = [{
+    Remembers the current state of the function stack. Returns a pointer
+    that later can be passed into cir.stack_restore.
+    Useful for implementing language features like variable length arrays.
+
+    ```mlir
+    %0 = cir.stack_save : <!u8i>
+    ```
+  }];
+
+  let results = (outs CIR_PointerType:$result);
+  let assemblyFormat = "attr-dict `:` qualified(type($result))";
+}
+
+def StackRestoreOp : CIR_Op<"stack_restore"> {
+  let summary = "restores the state of the function stack";
+  let description = [{
+    Restore the state of the function stack to the state it was
+    in when the corresponding cir.stack_save executed.
+    Useful for implementing language features like variable length arrays.
+
+    ```mlir
+    %0 = cir.alloca !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>, ["saved_stack"] {alignment = 8 : i64}
+    %1 = cir.stack_save : <!u8i>
+    cir.store %1, %0 : !cir.ptr<!u8i>, !cir.ptr<!cir.ptr<!u8i>>
+    %2 = cir.load %0 : !cir.ptr<!cir.ptr<!u8i>>, !cir.ptr<!u8i>
+    cir.stack_restore %2 : !cir.ptr<!u8i>
+    ```
+  }];
+
+  let arguments = (ins CIR_PointerType:$ptr);
+  let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
+
+  let llvmOp = "StackRestoreOp";
+}
+
 //===----------------------------------------------------------------------===//
 // UnreachableOp
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 8c4a67258df3f..0673b1543d91e 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1467,6 +1467,8 @@ void ConvertCIRToLLVMPass::runOnOperation() {
                CIRToLLVMConstantOpLowering,
                CIRToLLVMFuncOpLowering,
                CIRToLLVMGetGlobalOpLowering,
+               CIRToLLVMStackSaveOpLowering,
+               CIRToLLVMStackRestoreOpLowering,
                CIRToLLVMTrapOpLowering,
                CIRToLLVMUnaryOpLowering
       // clang-format on
@@ -1512,6 +1514,22 @@ mlir::LogicalResult CIRToLLVMTrapOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMStackSaveOpLowering::matchAndRewrite(
+    cir::StackSaveOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  const mlir::Type ptrTy = getTypeConverter()->convertType(op.getType());
+  rewriter.replaceOpWithNewOp<mlir::LLVM::StackSaveOp>(op, ptrTy);
+  return mlir::success();
+}
+
+mlir::LogicalResult CIRToLLVMStackRestoreOpLowering::matchAndRewrite(
+    cir::StackRestoreOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  rewriter.replaceOpWithNewOp<mlir::LLVM::StackRestoreOp>(
+      op, adaptor.getOperands().front());
+  return mlir::success();
+}
+
 std::unique_ptr<mlir::Pass> createConvertCIRToLLVMPass() {
   return std::make_unique<ConvertCIRToLLVMPass>();
 }
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
index 1de6c9c56b485..a7c2704e13fe6 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -242,6 +242,26 @@ class CIRToLLVMPtrStrideOpLowering
   matchAndRewrite(cir::PtrStrideOp op, OpAdaptor,
                   mlir::ConversionPatternRewriter &) const override;
 };
+
+class CIRToLLVMStackSaveOpLowering
+    : public mlir::OpConversionPattern<cir::StackSaveOp> {
+public:
+  using mlir::OpConversionPattern<cir::StackSaveOp>::OpConversionPattern;
+  mlir::LogicalResult
+  matchAndRewrite(cir::StackSaveOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
+class CIRToLLVMStackRestoreOpLowering
+    : public mlir::OpConversionPattern<cir::StackRestoreOp> {
+public:
+  using OpConversionPattern<cir::StackRestoreOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::StackRestoreOp op, OpAdaptor adaptor,
+                  mlir::ConversionPatternRewriter &rewriter) const override;
+};
+
 } // namespace direct
 } // namespace cir
 
diff --git a/clang/test/CIR/IR/stack-save-restore.cir b/clang/test/CIR/IR/stack-save-restore.cir
new file mode 100644
index 0000000000000..f6027258786df
--- /dev/null
+++ b/clang/test/CIR/IR/stack-save-restore.cir
@@ -0,0 +1,23 @@
+// Test the CIR operations can parse and print correctly (roundtrip)
+
+// RUN: cir-opt %s | cir-opt | FileCheck %s
+
+!u8i = !cir.int<u, 8>
+
+module  {
+  cir.func @stack_save_restore() {
+    %0 = cir.stack_save : !cir.ptr<!u8i>
+    cir.stack_restore %0 : !cir.ptr<!u8i>
+    cir.return
+  }
+}
+
+//CHECK: module  {
+
+//CHECK-NEXT: cir.func @stack_save_restore() {
+//CHECK-NEXT:   %0 = cir.stack_save : !cir.ptr<!u8i>
+//CHECK-NEXT:   cir.stack_restore %0 : !cir.ptr<!u8i>
+//CHECK-NEXT:   cir.return
+//CHECK-NEXT: }
+
+//CHECK-NEXT: }
diff --git a/clang/test/CIR/Lowering/stack-save-restore.cir b/clang/test/CIR/Lowering/stack-save-restore.cir
new file mode 100644
index 0000000000000..ad9dee66b53f5
--- /dev/null
+++ b/clang/test/CIR/Lowering/stack-save-restore.cir
@@ -0,0 +1,19 @@
+// RUN: cir-opt %s -cir-to-llvm -o - | FileCheck %s -check-prefix=MLIR
+
+!u8i = !cir.int<u, 8>
+
+module  {
+  cir.func @stack_save() {
+    %0 = cir.stack_save : !cir.ptr<!u8i>
+    cir.stack_restore %0 : !cir.ptr<!u8i>
+    cir.return
+  }
+}
+
+//      MLIR: module {
+// MLIR-NEXT:  llvm.func @stack_save
+// MLIR-NEXT:    %0 = llvm.intr.stacksave : !llvm.ptr
+// MLIR-NEXT:    llvm.intr.stackrestore %0 : !llvm.ptr
+// MLIR-NEXT:    llvm.return
+// MLIR-NEXT:  }
+// MLIR-NEXT: }

xlauko · 2025-04-21T07:51:34Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+// StackSave & StackRestoreOp
+//===----------------------------------------------------------------------===//
+
+def StackSaveOp : CIR_Op<"stack_save"> {


nit: These should probably mention that operations correspond and mirror semantics of llvm.stacksave and llvm.stackrestore intrinsics.

nit: Also any reason not to mirror llvm names, i.e. to have cir.stacksave and cir.stackrestore?

nit: Also any reason not to mirror llvm names, i.e. to have cir.stacksave and cir.stackrestore?

I found that we use the same name pattern in general, for example get_global, ptr_stride ...etc, but I think in this case we can mirror the llvm names, I will update it

Mmmmm, I think that llvm in general uses the same style without _ for example getElemenetPtr, but in CIR dialect we use different style, not sure if it make sense to rename stack_save to stacksave or not, what do you think @xlauko 🤔

Edit: Another example we have is insertvalue and insert_value

yeah, probably generic question on @bcardosolopes @andykaylor what should be the policy? I don't mind either.

Thanks for bringing up the consistency angle here. We have been telling people to use snake_case: https://llvm.github.io/clangir/Dialect/cir-style-guide.html, though I see a good point in matching LLVM when it makes sense (like in this case). I don't have a strong opinion here other than bigger names looks better with _ breaking them down. Maybe we should extend the doc to make things similar to LLVM when is the case?

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h

xlauko · 2025-04-21T08:06:12Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+  let arguments = (ins CIR_PointerType:$ptr);
+  let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
+
+  let llvmOp = "StackRestoreOp";


Why is this here, since it is not used? Also it is only in one of these operations.

If used, I would expect not to have explicit CIRToLLVMStackRestoreOpLowering and CIRToLLVMStackSaveOpLowering patterns, but use the generated one.

xlauko · 2025-04-21T17:22:33Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+    that later can be passed into cir.stack_restore.
+    Useful for implementing language features like variable length arrays.
+
+    This operation is correspond to LLVM intrinsic `stacksave`.


Suggested change

This operation is correspond to LLVM intrinsic `stacksave`.

This operation corresponds to LLVM intrinsic `stacksave`.

xlauko · 2025-04-21T17:22:43Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+    in when the corresponding cir.stack_save executed.
+    Useful for implementing language features like variable length arrays.
+
+    This operation is correspond to LLVM intrinsic `stackrestore`.


Suggested change

This operation is correspond to LLVM intrinsic `stackrestore`.

This operation corresponds to LLVM intrinsic `stackrestore`.

bcardosolopes

The PR looks good overall, it adds the operation, tests for parsing/printing + LLVM lowering, leaving CIRGen to support to be done incrementally. LGTM once the operation names are used consistently.

andykaylor

Looks good, with a couple of minor requests.

andykaylor · 2025-04-21T19:17:11Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

@@ -1419,6 +1419,50 @@ def CallOp : CIR_CallOpBase<"call", [NoRegionArguments]> {
    }]>];
 }

+//===----------------------------------------------------------------------===//
+// StackSave & StackRestoreOp


Suggested change

// StackSave & StackRestoreOp

// StackSaveOp & StackRestoreOp

For consistency, though I'm not sure why there are combined.

andykaylor · 2025-04-21T19:20:45Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+def StackSaveOp : CIR_Op<"stacksave"> {
+  let summary = "remembers the current state of the function stack";
+  let description = [{
+    Remembers the current state of the function stack. Returns a pointer


Suggested change

Remembers the current state of the function stack. Returns a pointer

Saves current state of the function stack. Returns a pointer to an opaque object

andykaylor · 2025-04-21T19:22:05Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+  let description = [{
+    Remembers the current state of the function stack. Returns a pointer
+    that later can be passed into cir.stackrestore.
+    Useful for implementing language features like variable length arrays.


Suggested change

Useful for implementing language features like variable length arrays.

This is used during the lowering of variable length array allocas.

andykaylor · 2025-04-21T19:22:45Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+  let description = [{
+    Restore the state of the function stack to the state it was
+    in when the corresponding cir.stacksave executed.
+    Useful for implementing language features like variable length arrays.


Suggested change

Useful for implementing language features like variable length arrays.

This is used during the lowering of variable length array allocas.

andykaylor · 2025-04-21T19:25:29Z

clang/test/CIR/Lowering/stack-save-restore.cir

@@ -0,0 +1,19 @@
+// RUN: cir-opt %s -cir-to-llvm -o - | FileCheck %s -check-prefix=MLIR


Can you also add a RUN line to lower this to LLVM IR?

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

[CIR] Upstream StackSave and StackRestoreOp

91a6937

AmrDeveloper requested review from AaronBallman, xlauko, erichkeane, dkolsen-pgi and andykaylor April 19, 2025 12:28

AmrDeveloper requested review from lanza and bcardosolopes as code owners April 19, 2025 12:28

llvmbot added clang Clang issues not falling into any other category ClangIR Anything related to the ClangIR project labels Apr 19, 2025

xlauko reviewed Apr 21, 2025

View reviewed changes

Address code review comments

015a2a9

xlauko reviewed Apr 21, 2025

View reviewed changes

bcardosolopes approved these changes Apr 21, 2025

View reviewed changes

Update stack operations names

88ffbd9

andykaylor approved these changes Apr 21, 2025

View reviewed changes

AmrDeveloper added 2 commits April 21, 2025 21:51

Add run line for lower to LLVM IR

bb865d2

Merge branch 'main' into cir_upstream_stack_op

1ecbfe8

AmrDeveloper merged commit 80872d7 into llvm:main Apr 22, 2025
9 of 10 checks passed

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request May 6, 2025

[CIR] Upstream StackSave and StackRestoreOp (llvm#136426)

704cfbf

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request May 6, 2025

[CIR] Upstream StackSave and StackRestoreOp (llvm#136426)

da6cb93

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request May 6, 2025

[CIR] Upstream StackSave and StackRestoreOp (llvm#136426)

7b4953d

This change adds support for StackSave and StackRestoreOp as a preliminary patch of VLA support

	This operation is correspond to LLVM intrinsic `stacksave`.
	This operation corresponds to LLVM intrinsic `stacksave`.

	// StackSave & StackRestoreOp
	// StackSaveOp & StackRestoreOp

	Remembers the current state of the function stack. Returns a pointer
	Saves current state of the function stack. Returns a pointer to an opaque object

	Useful for implementing language features like variable length arrays.
	This is used during the lowering of variable length array allocas.

		@@ -0,0 +1,19 @@
		// RUN: cir-opt %s -cir-to-llvm -o - \| FileCheck %s -check-prefix=MLIR

[CIR] Upstream StackSave and StackRestoreOp #136426

[CIR] Upstream StackSave and StackRestoreOp #136426

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AmrDeveloper Apr 21, 2025 •

edited

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