[clang][OpenCL] Only evaluate initializer once to check for zero init

[tbaederr]

Both Expr::isIntegerConstantExpr() and Epxr::EvaluateKnownConstInt() evaluate the expression. Just do it once and check the integer result.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

Changes

Both Expr::isIntegerConstantExpr() and Epxr::EvaluateKnownConstInt() evaluate the expression. Just do it once and check the integer result.

---

Full diff: https://github.com/llvm/llvm-project/pull/141474.diff

1 Files Affected:

• (modified) clang/lib/Sema/SemaInit.cpp (+5-5)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 2f682dbc1f000..776cb022e6925 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -6410,9 +6410,9 @@ static bool TryOCLSamplerInitialization(Sema &S,
   return true;
 }
 
-static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
-  return Initializer->isIntegerConstantExpr(S.getASTContext()) &&
-    (Initializer->EvaluateKnownConstInt(S.getASTContext()) == 0);
+static bool IsZeroInitializer(const Expr *Init, ASTContext &Ctx) {
+  std::optional<llvm::APSInt> Value = Init->getIntegerConstantExpr(Ctx);
+  return Value && Value->isZero();
 }
 
 static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
@@ -6431,7 +6431,7 @@ static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
   // event should be zero.
   //
   if (DestType->isEventT() || DestType->isQueueT()) {
-    if (!IsZeroInitializer(Initializer, S))
+    if (!IsZeroInitializer(Initializer, S.getASTContext()))
       return false;
 
     Sequence.AddOCLZeroOpaqueTypeStep(DestType);
@@ -6447,7 +6447,7 @@ static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
     if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
         DestType->isOCLIntelSubgroupAVCMceResultType())
       return false;
-    if (!IsZeroInitializer(Initializer, S))
+    if (!IsZeroInitializer(Initializer, S.getASTContext()))
       return false;
 
     Sequence.AddOCLZeroOpaqueTypeStep(DestType);

[asavonic]

Good catch, LGTM.