[CHERI] Fix Clang code generation for _Atomic(uintptr_t)

Author: resistor

clang/lib/CodeGen/CGExprScalar.cpp

@@ -3355,9 +3355,10 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
         !(type->isUnsignedIntegerType() &&
           CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) &&
         CGF.getLangOpts().getSignedOverflowBehavior() !=
-            LangOptions::SOB_Trapping) {
-      llvm::AtomicRMWInst::BinOp aop = isInc ? llvm::AtomicRMWInst::Add :
-        llvm::AtomicRMWInst::Sub;
+            LangOptions::SOB_Trapping &&
+        !type->isCHERICapabilityType(CGF.getContext())) {
+      llvm::AtomicRMWInst::BinOp aop =
+          isInc ? llvm::AtomicRMWInst::Add : llvm::AtomicRMWInst::Sub;
       llvm::Instruction::BinaryOps op = isInc ? llvm::Instruction::Add :
         llvm::Instruction::Sub;
       llvm::Value *amt = CGF.EmitToMemory(

clang/test/CodeGen/cheri/riscv/cheriot-atomic-uintptr.c

@@ -0,0 +1,38 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
+// RUN: %clang_cc1 %s -o - "-triple" "riscv32cheriot-unknown-unknown" "-emit-llvm" "-mframe-pointer=none" "-mcmodel=small" "-target-abi" "cheriot" "-Oz" "-Werror" -std=c2x | FileCheck %s
+
+// Check that we can generate code for C11 atomic increment of uintptr
+
+// CHECK-LABEL: define dso_local void @test1(
+// CHECK-SAME: ) local_unnamed_addr addrspace(200) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*]]:
+// CHECK-NEXT:    [[P:%.*]] = alloca ptr addrspace(200), align 8, addrspace(200)
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca ptr addrspace(200), align 8, addrspace(200)
+// CHECK-NEXT:    [[ATOMIC_TEMP1:%.*]] = alloca ptr addrspace(200), align 8, addrspace(200)
+// CHECK-NEXT:    [[ATOMIC_TEMP2:%.*]] = alloca ptr addrspace(200), align 8, addrspace(200)
+// CHECK-NEXT:    call void @llvm.lifetime.start.p200(i64 8, ptr addrspace(200) nonnull [[P]]) #[[ATTR4:[0-9]+]]
+// CHECK-NEXT:    call cherilibcallcc void @__atomic_load(i32 noundef 8, ptr addrspace(200) noundef nonnull [[P]], ptr addrspace(200) noundef nonnull [[ATOMIC_TEMP]], i32 noundef 5) #[[ATTR5:[0-9]+]]
+// CHECK-NEXT:    br label %[[ATOMIC_OP:.*]]
+// CHECK:       [[ATOMIC_OP]]:
+// CHECK-NEXT:    [[DOTIN:%.*]] = phi ptr addrspace(200) [ [[ATOMIC_TEMP]], %[[ENTRY]] ], [ [[ATOMIC_TEMP1]], %[[ATOMIC_OP]] ]
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr addrspace(200), ptr addrspace(200) [[DOTIN]], align 8, !tbaa [[TBAA7:![0-9]+]]
+// CHECK-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr addrspace(200) [[TMP0]], i32 1
+// CHECK-NEXT:    store ptr addrspace(200) [[TMP0]], ptr addrspace(200) [[ATOMIC_TEMP1]], align 8, !tbaa [[TBAA11:![0-9]+]]
+// CHECK-NEXT:    store ptr addrspace(200) [[TMP1]], ptr addrspace(200) [[ATOMIC_TEMP2]], align 8, !tbaa [[TBAA11]]
+// CHECK-NEXT:    [[CALL:%.*]] = call cherilibcallcc zeroext i1 @__atomic_compare_exchange(i32 noundef 8, ptr addrspace(200) noundef nonnull [[P]], ptr addrspace(200) noundef nonnull [[ATOMIC_TEMP1]], ptr addrspace(200) noundef nonnull [[ATOMIC_TEMP2]], i32 noundef 5, i32 noundef 5) #[[ATTR5]]
+// CHECK-NEXT:    br i1 [[CALL]], label %[[ATOMIC_CONT:.*]], label %[[ATOMIC_OP]]
+// CHECK:       [[ATOMIC_CONT]]:
+// CHECK-NEXT:    call void @llvm.lifetime.end.p200(i64 8, ptr addrspace(200) nonnull [[P]]) #[[ATTR4]]
+// CHECK-NEXT:    ret void
+//
+void test1() {
+  _Atomic(__UINTPTR_TYPE__) p;
+  ++p;
+}
+//.
+// CHECK: [[TBAA7]] = !{[[META8:![0-9]+]], [[META8]], i64 0}
+// CHECK: [[META8]] = !{!"unsigned __intcap", [[META9:![0-9]+]], i64 0}
+// CHECK: [[META9]] = !{!"omnipotent char", [[META10:![0-9]+]], i64 0}
+// CHECK: [[META10]] = !{!"Simple C/C++ TBAA"}
+// CHECK: [[TBAA11]] = !{[[META9]], [[META9]], i64 0}
+//.