Reland r374450 with Richard Smith's comments and test fixed.
The behavior from the original patch has changed, since we're no longer
allowing LLVM to just ignore the alignment. Instead, we're just
assuming the maximum possible alignment.
Differential Revision: https://reviews.llvm.org/D68824
llvm-svn: 374562
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 0562a62..ddff595 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2048,11 +2048,13 @@
Value *AlignmentValue = EmitScalarExpr(E->getArg(1));
ConstantInt *AlignmentCI = cast<ConstantInt>(AlignmentValue);
- unsigned Alignment = (unsigned)AlignmentCI->getZExtValue();
+ if (AlignmentCI->getValue().ugt(llvm::Value::MaximumAlignment))
+ AlignmentCI = ConstantInt::get(AlignmentCI->getType(),
+ llvm::Value::MaximumAlignment);
EmitAlignmentAssumption(PtrValue, Ptr,
/*The expr loc is sufficient.*/ SourceLocation(),
- Alignment, OffsetValue);
+ AlignmentCI, OffsetValue);
return RValue::get(PtrValue);
}
case Builtin::BI__assume: