[clang] Add range metadata for atomic load of boolean type. #131476 (PR #133546)

[Jan Górski via cfe-commits]

https://github.com/janagor created 
https://github.com/llvm/llvm-project/pull/133546

Addresses #131476.

For `x86_64` it folds
```
movzbl  t1(%rip), %eax
andb    $1, %al
```
into
```
movzbl  t1(%rip), %eax
```
when run: `clang -S atomic-ops-load.c -o atomic-ops-load.s -O1 --target=x86_64`.

But for riscv replaces:
```
lb      a0, %lo(t1)(a0)
andi    a0, a0, 1
```
with
```
lb      a0, %lo(t1)(a0)
zext.b  a0, a0
``` 
when run: `when run `clang -S atomic-ops-load.c -o atomic-ops-load.s -O1 
--target=riscv64`.

 

From 4581169d6fbe72357bb83b95fe36c8cc606efa1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20G=C3=B3rski?= <jan.a.gor...@wp.pl>
Date: Fri, 28 Mar 2025 23:36:18 +0100
Subject: [PATCH 1/3] [clang][CodeGen] Added llvm ir pre-commit test.

---
 clang/test/CodeGen/atomic-ops-load.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 clang/test/CodeGen/atomic-ops-load.c

diff --git a/clang/test/CodeGen/atomic-ops-load.c 
b/clang/test/CodeGen/atomic-ops-load.c
new file mode 100644
index 0000000000000..adcaf9a2112fa
--- /dev/null
+++ b/clang/test/CodeGen/atomic-ops-load.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple riscv64 -O1 -emit-llvm %s -o - | FileCheck %s
+#include <stdbool.h>
+
+extern bool t1;
+bool test1(void) {
+// CHECK-LABEL: define{{.*}} i1 @test1
+// CHECK: load atomic i8, ptr @t1 monotonic, align 1
+// CHECK-NEXT: trunc i8 %{{.*}} to i1
+// CHECK-NEXT: ret i1 %{{.*}}
+  return __atomic_load_n(&t1, __ATOMIC_RELAXED);
+}

From 852b691fac487b3cef7b0df8875c26573bc58daa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20G=C3=B3rski?= <jan.a.gor...@wp.pl>
Date: Sat, 29 Mar 2025 00:53:23 +0100
Subject: [PATCH 2/3] [clang][CodeGen] Added `!range` metadata to atomic load
 for `bool`.

---
 clang/lib/CodeGen/CGAtomic.cpp       | 23 +++++++++++++++++++++++
 clang/test/CodeGen/atomic-ops-load.c |  4 ++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/clang/lib/CodeGen/CGAtomic.cpp b/clang/lib/CodeGen/CGAtomic.cpp
index 3adb2a7ad207f..70ae7180a9adc 100644
--- a/clang/lib/CodeGen/CGAtomic.cpp
+++ b/clang/lib/CodeGen/CGAtomic.cpp
@@ -590,6 +590,29 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr 
*E, Address Dest,
     llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr);
     Load->setAtomic(Order, Scope);
     Load->setVolatile(E->isVolatile());
+
+    if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
+      CGF.Builder.CreateStore(Load, Dest);
+      return;
+    }
+
+    QualType Ty = E->getValueType();
+    if (!Ty->isBooleanType()) {
+      CGF.Builder.CreateStore(Load, Dest);
+      return;
+    }
+
+    llvm::MDBuilder MDHelper(CGF.getLLVMContext());
+    llvm::APInt BooleanMin = llvm::APInt(CGF.getContext().getTypeSize(Ty), 0);
+    llvm::APInt BooleanEnd = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2);
+
+    if (llvm::MDNode *RangeInfo =
+        MDHelper.createRange(BooleanMin, BooleanEnd)) {
+      Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo);
+      Load->setMetadata(llvm::LLVMContext::MD_noundef,
+          llvm::MDNode::get(CGF.getLLVMContext(), {}));
+    }
+
     CGF.Builder.CreateStore(Load, Dest);
     return;
   }
diff --git a/clang/test/CodeGen/atomic-ops-load.c 
b/clang/test/CodeGen/atomic-ops-load.c
index adcaf9a2112fa..778a7ebdc2618 100644
--- a/clang/test/CodeGen/atomic-ops-load.c
+++ b/clang/test/CodeGen/atomic-ops-load.c
@@ -4,8 +4,8 @@
 extern bool t1;
 bool test1(void) {
 // CHECK-LABEL: define{{.*}} i1 @test1
-// CHECK: load atomic i8, ptr @t1 monotonic, align 1
-// CHECK-NEXT: trunc i8 %{{.*}} to i1
+// CHECK: load atomic i8, ptr @t1 monotonic, align 1, !range 
![[$WS_RANGE:[0-9]*]], !noundef !{{[0-9]+}}
+// CHECK-NEXT: trunc nuw i8 %{{.*}} to i1
 // CHECK-NEXT: ret i1 %{{.*}}
   return __atomic_load_n(&t1, __ATOMIC_RELAXED);
 }

From e42772bbc0851696d73ded4abc3edf651f4e8b41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20G=C3=B3rski?= <jan.a.gor...@wp.pl>
Date: Sat, 29 Mar 2025 01:12:18 +0100
Subject: [PATCH 3/3] Updated codestyle.

---
 clang/lib/CodeGen/CGAtomic.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clang/lib/CodeGen/CGAtomic.cpp b/clang/lib/CodeGen/CGAtomic.cpp
index 70ae7180a9adc..2c9613deef744 100644
--- a/clang/lib/CodeGen/CGAtomic.cpp
+++ b/clang/lib/CodeGen/CGAtomic.cpp
@@ -607,10 +607,10 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr 
*E, Address Dest,
     llvm::APInt BooleanEnd = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2);
 
     if (llvm::MDNode *RangeInfo =
-        MDHelper.createRange(BooleanMin, BooleanEnd)) {
+            MDHelper.createRange(BooleanMin, BooleanEnd)) {
       Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo);
       Load->setMetadata(llvm::LLVMContext::MD_noundef,
-          llvm::MDNode::get(CGF.getLLVMContext(), {}));
+                        llvm::MDNode::get(CGF.getLLVMContext(), {}));
     }
 
     CGF.Builder.CreateStore(Load, Dest);

_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits