[clang] 2e6433b - [clang] Emit convergence tokens for loop in global array init (#140120)

[via cfe-commits]

Author: Steven Perron
Date: 2025-05-15T17:44:34-04:00
New Revision: 2e6433b8293ac64923c737078e87dc39fc4bced6

URL: https://github.com/llvm/llvm-project/commit/2e6433b8293ac64923c737078e87dc39fc4bced6
DIFF: https://github.com/llvm/llvm-project/commit/2e6433b8293ac64923c737078e87dc39fc4bced6.diff

LOG: [clang] Emit convergence tokens for loop in global array init (#140120)

When initializing a global array, a loop is generated, but no
convergence is emitted for the loop. This fixes that up.

Added: 
    clang/test/CodeGenHLSL/convergence/global_array.hlsl

Modified: 
    clang/lib/CodeGen/CGClass.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index befbfc64a680c..44062739d5dd4 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -2042,6 +2042,8 @@ void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
   cur->addIncoming(arrayBegin, entryBB);
 
   // Inside the loop body, emit the constructor call on the array element.
+  if (CGM.shouldEmitConvergenceTokens())
+    ConvergenceTokenStack.push_back(emitConvergenceLoopToken(loopBB));
 
   // The alignment of the base, adjusted by the size of a single element,
   // provides a conservative estimate of the alignment of every element.
@@ -2101,6 +2103,9 @@ void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
   // Patch the earlier check to skip over the loop.
   if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
 
+  if (CGM.shouldEmitConvergenceTokens())
+    ConvergenceTokenStack.pop_back();
+
   EmitBlock(contBB);
 }
 

diff  --git a/clang/test/CodeGenHLSL/convergence/global_array.hlsl b/clang/test/CodeGenHLSL/convergence/global_array.hlsl
new file mode 100644
index 0000000000000..e11de82c3ded0
--- /dev/null
+++ b/clang/test/CodeGenHLSL/convergence/global_array.hlsl
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -Wno-hlsl-implicit-binding -finclude-default-header -triple spirv-unknown-vulkan-compute -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+
+// CHECK: define internal spir_func void @__cxx_global_var_init()
+// CHECK: [[entry_token:%.*]] = call token @llvm.experimental.convergence.entry()
+// CHECK: br label %[[loop_entry:.*]]
+
+// CHECK: [[loop_entry]]:
+// CHECK: [[loop_token:%.*]] = call token @llvm.experimental.convergence.loop() [ "convergencectrl"(token [[entry_token]]) ]
+// CHECK: call void {{.*}} [ "convergencectrl"(token [[loop_token]]) ]
+// CHECK: br i1 {{%.*}} label {{%.*}} label %[[loop_entry]]
+RWBuffer<float> e[2];
+
+[numthreads(4,1,1)]
+void main() {
+}
+