[clang] 1bbac05 - [clang][bytecode] Fix ignoring comparisons in C (#156180)

[via cfe-commits]

Author: Timm Baeder
Date: 2025-08-30T17:41:08+02:00
New Revision: 1bbac057f6de10db683e70c8c966809ad576b93e

URL: https://github.com/llvm/llvm-project/commit/1bbac057f6de10db683e70c8c966809ad576b93e
DIFF: https://github.com/llvm/llvm-project/commit/1bbac057f6de10db683e70c8c966809ad576b93e.diff

LOG: [clang][bytecode] Fix ignoring comparisons in C (#156180)

Our comparison ops always return bool, and we do the pop before the
conversion to in in C.

Fixes #156178

Added: 
    

Modified: 
    clang/lib/AST/ByteCode/Compiler.cpp
    clang/test/AST/ByteCode/c.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index c314f0a132196..56552f3969216 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -942,7 +942,7 @@ bool Compiler<Emitter>::VisitBinaryOperator(const BinaryOperator *BO) {
     if (!Result)
       return false;
     if (DiscardResult)
-      return this->emitPop(*T, BO);
+      return this->emitPopBool(BO);
     if (T != PT_Bool)
       return this->emitCast(PT_Bool, *T, BO);
     return true;

diff  --git a/clang/test/AST/ByteCode/c.c b/clang/test/AST/ByteCode/c.c
index 05af00c040f45..b6d2a69271afb 100644
--- a/clang/test/AST/ByteCode/c.c
+++ b/clang/test/AST/ByteCode/c.c
@@ -362,3 +362,9 @@ void bar() { // pedantic-warning {{a function declaration without a prototype}}
   int x;
   x = foo(); // all-warning {{too few arguments}}
 }
+
+int *_b = &a;
+void discardedCmp(void)
+{
+    (*_b) = ((&a == &a) , a); // all-warning {{left operand of comma operator has no effect}}
+}