When "low alignment" is specified, then set the alignment of the aggregate's
store to 1. This allows code-gen to select a more appropriate alignment. If left
to zero, an alignment greater than the alignment of the pointer may be selected,
causing code-gen to use instructions which require an alignment greater than the
pointer guarantees.
<rdar://problem/11043589>
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152951 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 4fe4fa8..4455f1a 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -623,7 +623,9 @@
SI->setAlignment(1);
}
} else {
- CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile);
+ llvm::StoreInst *SI = CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile);
+ if (LowAlignment)
+ SI->setAlignment(1);
}
}
diff --git a/test/CodeGenCXX/2012-03-16-StoreAlign.cpp b/test/CodeGenCXX/2012-03-16-StoreAlign.cpp
new file mode 100644
index 0000000..c2c7548
--- /dev/null
+++ b/test/CodeGenCXX/2012-03-16-StoreAlign.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -emit-llvm -o - -triple x86_64-apple-darwin %s | FileCheck %s
+// <rdar://problem/11043589>
+
+struct Length {
+ Length(double v) {
+ m_floatValue = static_cast<float>(v);
+ }
+
+ bool operator==(const Length& o) const {
+ return getFloatValue() == o.getFloatValue();
+ }
+ bool operator!=(const Length& o) const { return !(*this == o); }
+private:
+ float getFloatValue() const {
+ return m_floatValue;
+ }
+ float m_floatValue;
+};
+
+
+struct Foo {
+ static Length inchLength(double inch);
+ static bool getPageSizeFromName(const Length &A) {
+ static const Length legalWidth = inchLength(8.5);
+ if (A != legalWidth) return true;
+ return false;
+ }
+};
+
+// CHECK: @_ZZN3Foo19getPageSizeFromNameERK6LengthE10legalWidth = linkonce_odr global %struct.Length zeroinitializer, align 4
+// CHECK: store float %call, float* getelementptr inbounds (%struct.Length* @_ZZN3Foo19getPageSizeFromNameERK6LengthE10legalWidth, i32 0, i32 0), align 1
+
+bool bar(Length &b) {
+ Foo f;
+ return f.getPageSizeFromName(b);
+}
