[CIR][CirGen][Bugfix] Fixes __sync_fetch_and_add for unsigned integers (

llvm#799)

`__sync_fetch_and_add` currently doesn't support unsigned integers. 

The following code snippet, for example, raises an error:  
```
#include <stdint.h>

void foo(uint64_t x) {
  __sync_fetch_and_add(&x, 1);
}
```
The error can be traced down to this line `auto intType =
builder.getSIntNTy(cgf.getContext().getTypeSize(typ));` from
`clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp`.

clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp

@@ -240,7 +240,10 @@ makeBinaryAtomicValue(CIRGenFunction &cgf, mlir::cir::AtomicFetchKind kind,
 
   Address destAddr = checkAtomicAlignment(cgf, expr);
   auto &builder = cgf.getBuilder();
-  auto intType = builder.getSIntNTy(cgf.getContext().getTypeSize(typ));
+  auto intType =
+      expr->getArg(0)->getType()->getPointeeType()->isUnsignedIntegerType()
+          ? builder.getUIntNTy(cgf.getContext().getTypeSize(typ))
+          : builder.getSIntNTy(cgf.getContext().getTypeSize(typ));
   mlir::Value val = cgf.buildScalarExpr(expr->getArg(1));
   mlir::Type valueType = val.getType();
   val = buildToInt(cgf, val, typ, intType);

clang/test/CIR/CodeGen/atomic.cpp

@@ -471,3 +471,30 @@ void cmp_val_short(short* p, short x, short u) {
 void cmp_val_byte(char* p, char x, char u) {
   char r = __sync_val_compare_and_swap(p, x, u);
 }
+
+// CHECK-LABEL: @_Z8inc_uint
+// CHECK: cir.atomic.fetch(add, {{.*}} : !cir.ptr<!u32i>, {{.*}} : !u32i, seq_cst) fetch_first : !u32i
+
+// LLVM-LABEL: @_Z8inc_uint
+// LLVM: atomicrmw add ptr {{.*}}, i32 {{.*}} seq_cst, align 4
+void inc_uint(unsigned int* a, int b) {
+  unsigned int c = __sync_fetch_and_add(a, b);
+}
+
+// CHECK-LABEL: @_Z9inc_ulong
+// CHECK: cir.atomic.fetch(add, {{.*}} : !cir.ptr<!u64i>, {{.*}} : !u64i, seq_cst) fetch_first : !u64i
+
+// LLVM-LABEL: @_Z9inc_ulong
+// LLVM: atomicrmw add ptr {{.*}}, i64 {{.*}} seq_cst, align 8
+void inc_ulong(unsigned long* a, long b) {
+  unsigned long c = __sync_fetch_and_add(a, b);
+}
+
+// CHECK-LABEL: @_Z9inc_uchar
+// CHECK: cir.atomic.fetch(add, {{.*}} : !cir.ptr<!u8i>, {{.*}} : !u8i, seq_cst) fetch_first : !u8i
+
+// LLVM-LABEL: @_Z9inc_uchar
+// LLVM: atomicrmw add ptr {{.*}}, i8 {{.*}} seq_cst, align 1
+void inc_uchar(unsigned char* a, char b) {
+  unsigned char c = __sync_fetch_and_add(a, b);
+}

clang/test/CodeGen/atomic.c

@@ -160,4 +160,4 @@ void force_global_uses(void) {
   // X86:      call void @__atomic_load(i32 noundef 16, ptr noundef @glob_longdbl, ptr noundef %atomic-temp
   // X86-NEXT: %0 = load x86_fp80, ptr %atomic-temp, align 16
   // SYSTEMZ: load atomic fp128, ptr @[[GLOB_LONGDBL]] seq_cst
-}
+}