[PATCH] D124736: [CodeGen] Use ABI alignment for placement new

[Daniel Bertalan via Phabricator via cfe-commits]

BertalanD updated this revision to Diff 426301.
BertalanD added a comment.

Added a test case.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124736/new/

https://reviews.llvm.org/D124736

Files:
  clang/lib/CodeGen/CGExprCXX.cpp
  clang/test/CodeGenCXX/pr54845.cpp


Index: clang/test/CodeGenCXX/pr54845.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/pr54845.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -triple i686-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// https://github.com/llvm/llvm-project/issues/54845
+
+void *operator new(unsigned int, void *);
+
+void test(double *d) {
+  // This store used to have an alignment of 8, which was incorrect as
+  // the i386 psABI only guarantees a 4-byte alignment for doubles.
+
+  // CHECK: store double 0.000000e+00, {{.*}}, align 4
+  new (d) double(0);
+}
Index: clang/lib/CodeGen/CGExprCXX.cpp
===================================================================
--- clang/lib/CodeGen/CGExprCXX.cpp
+++ clang/lib/CodeGen/CGExprCXX.cpp
@@ -1573,7 +1573,7 @@
   llvm::Value *allocSize =
     EmitCXXNewAllocSize(*this, E, minElements, numElements,
                         allocSizeWithoutCookie);
-  CharUnits allocAlign = getContext().getPreferredTypeAlignInChars(allocType);
+  CharUnits allocAlign;
 
   // Emit the allocation call.  If the allocator is a global placement
   // operator, just "inline" it directly.
@@ -1583,6 +1583,8 @@
     assert(E->getNumPlacementArgs() == 1);
     const Expr *arg = *E->placement_arguments().begin();
 
+    allocAlign = getContext().getTypeAlignInChars(allocType);
+
     LValueBaseInfo BaseInfo;
     allocation = EmitPointerWithAlignment(arg, &BaseInfo);
 
@@ -1605,6 +1607,8 @@
       allocator->getType()->castAs<FunctionProtoType>();
     unsigned ParamsToSkip = 0;
 
+    allocAlign = getContext().getPreferredTypeAlignInChars(allocType);
+
     // The allocation size is the first argument.
     QualType sizeType = getContext().getSizeType();
     allocatorArgs.add(RValue::get(allocSize), sizeType);


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