[PATCH] D43734: [RecordLayout] Don't align to non-power-of-2 sizes when using -mms-bitfields

Martin Storsjö via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Sat Feb 24 23:06:49 PST 2018


mstorsjo updated this revision to Diff 135813.
mstorsjo added a comment.

Asserting that non power of 2 only occurs in gnu mode.


https://reviews.llvm.org/D43734

Files:
  lib/AST/RecordLayoutBuilder.cpp
  test/CodeGen/mingw-long-double.c


Index: test/CodeGen/mingw-long-double.c
===================================================================
--- test/CodeGen/mingw-long-double.c
+++ test/CodeGen/mingw-long-double.c
@@ -1,5 +1,7 @@
 // RUN: %clang_cc1 -triple i686-windows-gnu -emit-llvm -o - %s \
 // RUN:    | FileCheck %s --check-prefix=GNU32
+// RUN: %clang_cc1 -triple i686-windows-gnu -emit-llvm -o - %s -mms-bitfields \
+// RUN:    | FileCheck %s --check-prefix=GNU32
 // RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s \
 // RUN:    | FileCheck %s --check-prefix=GNU64
 // RUN: %clang_cc1 -triple x86_64-windows-msvc -emit-llvm -o - %s \
Index: lib/AST/RecordLayoutBuilder.cpp
===================================================================
--- lib/AST/RecordLayoutBuilder.cpp
+++ lib/AST/RecordLayoutBuilder.cpp
@@ -1752,7 +1752,12 @@
       QualType T = Context.getBaseElementType(D->getType());
       if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
         CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
-        if (TypeSize > FieldAlign)
+        assert(
+            (llvm::isPowerOf2_64(TypeSize.getQuantity()) ||
+             Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) &&
+            "Non PowerOf2 size outside of GNU mode");
+        if (TypeSize > FieldAlign &&
+            llvm::isPowerOf2_64(TypeSize.getQuantity()))
           FieldAlign = TypeSize;
       }
     }


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