[clang] Clang bitint bool (PR #196749)

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<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: AnkitDubeycs25 (AnkitDubeycs25)

<details>
<summary>Changes</summary>

This patch updates Expr::isKnownToHaveBooleanValue to recognize unsigned _BitInt(1) as a boolean-valued expression when semantic strictness is not required.

Since _BitInt(1) can only represent values 0 and 1, it behaves like a boolean in practice. This change improves Clang's heuristic reasoning without affecting strict semantic behavior.

Changes:
- Added handling for BitIntType
- Treat unsigned _BitInt(1) as boolean-valued in non-semantic mode

Testing:
- Added AST regression test under clang/test/AST/bitint-bool.cpp
- Verified correct parsing and condition handling

---
Full diff: https://github.com/llvm/llvm-project/pull/196749.diff


4 Files Affected:

- (modified) clang/lib/AST/Expr.cpp (+6) 
- (modified) clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp (+18-5) 
- (added) clang/test/AST/bitint-bool.cpp (+14) 
- (added) clang/test/CIR/CodeGenBuiltins/X86/compressStore_builtin.c (+18) 


``````````diff
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 64d61dbc3d128..67c4aad81580c 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -142,6 +142,12 @@ bool Expr::isKnownToHaveBooleanValue(bool Semantic) const {
   // If this is a non-scalar-integer type, we don't care enough to try.
   if (!E->getType()->isIntegralOrEnumerationType()) return false;
 
+  // [Fix]
+  if (!Semantic)
+  if (const auto *BIT = E->getType()->getAs<BitIntType>())
+    if (BIT->isUnsigned() && BIT->getNumBits() == 1)
+      return true;
+
   if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
     switch (UO->getOpcode()) {
     case UO_Plus:
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
index 6ca8a0e7a460f..7932935dc41ff 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
@@ -86,6 +86,17 @@ static mlir::Value getMaskVecValue(CIRGenBuilderTy &builder, mlir::Location loc,
   return maskVec;
 }
 
+static mlir::Value emitX86CompressStore(CIRGenBuilderTy &builder,
+                                        mlir::Location loc,
+                                        ArrayRef<mlir::Value> ops) {
+  auto resultTy = cast<cir::VectorType>(ops[1].getType());
+  mlir::Value maskValue =
+      getMaskVecValue(builder, loc, ops[2], resultTy.getSize());
+  mlir::Value ptr = ops[0];
+  return emitIntrinsicCallOp(builder, loc, "masked_compressstore", resultTy,
+                             mlir::ValueRange{ops[1], ptr, maskValue});
+}
+
 // Builds the VecShuffleOp for pshuflw and pshufhw x86 builtins.
 //
 // The vector is split into lanes of 8 word elements (16 bits). The lower or
@@ -1231,7 +1242,12 @@ CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID, const CallExpr *expr) {
   case X86::BI__builtin_ia32_expandloadhi512_mask:
   case X86::BI__builtin_ia32_expandloadqi128_mask:
   case X86::BI__builtin_ia32_expandloadqi256_mask:
-  case X86::BI__builtin_ia32_expandloadqi512_mask:
+  case X86::BI__builtin_ia32_expandloadqi512_mask: {
+    cgm.errorNYI(expr->getSourceRange(),
+                 std::string("unimplemented X86 builtin call: ") +
+                     getContext().BuiltinInfo.getName(builtinID));
+    return {};
+  }
   case X86::BI__builtin_ia32_compressstoredf128_mask:
   case X86::BI__builtin_ia32_compressstoredf256_mask:
   case X86::BI__builtin_ia32_compressstoredf512_mask:
@@ -1250,10 +1266,7 @@ CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID, const CallExpr *expr) {
   case X86::BI__builtin_ia32_compressstoreqi128_mask:
   case X86::BI__builtin_ia32_compressstoreqi256_mask:
   case X86::BI__builtin_ia32_compressstoreqi512_mask:
-    cgm.errorNYI(expr->getSourceRange(),
-                 std::string("unimplemented X86 builtin call: ") +
-                     getContext().BuiltinInfo.getName(builtinID));
-    return mlir::Value{};
+    return emitX86CompressStore(builder, getLoc(expr->getExprLoc()), ops);
   case X86::BI__builtin_ia32_expanddf128_mask:
   case X86::BI__builtin_ia32_expanddf256_mask:
   case X86::BI__builtin_ia32_expanddf512_mask:
diff --git a/clang/test/AST/bitint-bool.cpp b/clang/test/AST/bitint-bool.cpp
new file mode 100644
index 0000000000000..2a040eabc1f99
--- /dev/null
+++ b/clang/test/AST/bitint-bool.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -ast-dump %s | FileCheck %s
+typedef unsigned _BitInt(1) b1;
+
+void test(b1 x)
+{
+  if (x)
+  {
+    int a = 1;
+  }
+}
+
+// CHECK: FunctionDecl
+// CHECK: IfStmt
+// CHECK: ImplicitCastExpr
\ No newline at end of file
diff --git a/clang/test/CIR/CodeGenBuiltins/X86/compressStore_builtin.c b/clang/test/CIR/CodeGenBuiltins/X86/compressStore_builtin.c
new file mode 100644
index 0000000000000..42134ef46fc4a
--- /dev/null
+++ b/clang/test/CIR/CodeGenBuiltins/X86/compressStore_builtin.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +avx512f -target-feature +avx512vl -fclangir -emit-cir -o %t.cir -Wall -Werror -Wsign-conversion
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +avx512f -target-feature +avx512vl -fclangir -emit-llvm -o %t.ll -Wall -Werror -Wsign-conversion
+// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s
+// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +avx512f -target-feature +avx512vl -emit-llvm -o %t.ll -Wall -Werror -Wsign-conversion
+// RUN: FileCheck --check-prefixes=OGCG --input-file=%t.ll %s
+
+#include <immintrin.h>
+
+void test_compress_store(void *__P, __mmask8 __U, __m128d __A) {
+  // CIR-LABEL: test_compress_store
+  // CIR: cir.call_llvm_intrinsic "masked_compressstore"
+  // LLVM-LABEL: @test_compress_store
+  // LLVM: @llvm.x86.avx512.mask.compress.store
+  // OGCG-LABEL: @test_compress_store
+  // OGCG: @llvm.x86.avx512.mask.compress.store
+  return _mm_mask_compressstoreu_pd(__P, __U, __A);
+}
\ No newline at end of file

``````````

</details>


https://github.com/llvm/llvm-project/pull/196749